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Supplementary cementing materials

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... In this context, one of the best-known examples is the valorization of metallurgical slags as a substitute for cementitious binders in concrete and brick production. Although the technical feasibility of metallurgic slags valorization as cementitious material has been widely demonstrated (see, among others, Pontikes and Snellings (2014), Panesar (2019) [3,4]), environmental consequences are not yet entirely understood. Metallurgic slags can completely (or partially) replace ordinary Portland cement (OPC), whose manufacturing is an extremely energy-intensive process, responsible for 7% of global anthropogenic carbon dioxide emissions [4]. ...
... In this context, one of the best-known examples is the valorization of metallurgical slags as a substitute for cementitious binders in concrete and brick production. Although the technical feasibility of metallurgic slags valorization as cementitious material has been widely demonstrated (see, among others, Pontikes and Snellings (2014), Panesar (2019) [3,4]), environmental consequences are not yet entirely understood. Metallurgic slags can completely (or partially) replace ordinary Portland cement (OPC), whose manufacturing is an extremely energy-intensive process, responsible for 7% of global anthropogenic carbon dioxide emissions [4]. ...
... Although the technical feasibility of metallurgic slags valorization as cementitious material has been widely demonstrated (see, among others, Pontikes and Snellings (2014), Panesar (2019) [3,4]), environmental consequences are not yet entirely understood. Metallurgic slags can completely (or partially) replace ordinary Portland cement (OPC), whose manufacturing is an extremely energy-intensive process, responsible for 7% of global anthropogenic carbon dioxide emissions [4]. Considering that OPC alone represents 76% of concrete carbon emissions [5], the substitution of OPC could represent a key factor for the sustainability of concrete. ...
Article
The interest in circular economy for the construction sector is constantly increasing, and Global Warming Potential (GWP) is often used to assess the carbon footprint of buildings and building materials. However, GWP presents some methodological challenges when assessing the environmental impacts of construction materials. Due to the long life of construction materials, GWP calculation should take into consideration also time-related aspects. However, in the current GWP, any temporal information is lost, making traditional static GWP better suited for retrospective assessment rather than forecasting purposes. Building on this need, this study uses a time-dependent GWP to assess the carbon footprint of two newly developed construction materials, produced through the recycling of industrial residues (stainless steel slag and industrial goethite). The results for both materials are further compared with the results of traditional ordinary Portland cement (OPC) based concrete, presenting similar characteristics. The results of the dynamic GWP (D_GWP) are also compared to the results of traditional static GWP (S_GWP), to see how the methodological development of D_GWP may influence the final environmental evaluation for construction materials. The results show the criticality of the recycling processes, especially in the case of goethite valorization. The analysis shows also that, although the D_GWP did not result in a shift in the ranking between the three materials compared with S_GWP, it provides a clearer picture of emission flows and their effect on climate change over time.
... For instance, compared to the 28-day compressive strength results, specimen T0-F0-C0 improved by 17.88%, while specimen T100-F0-C0 improved by 11.1% at 90 days. This is ascribed to the reaction of sulfate ions in TWW with Ca(OH) 2 and C 3 A, which, in turn, formed additional ettringite and disintegrated concrete matrix [83]. The obtained results agree with Asadollahfardi et al. [9], who reported a 6% decrease in the compressive strength of TWW concrete specimens. ...
... Asadollahfardi et al. [9] also reported a slight decrease in the flexural strength with TWW. Similar to compressive strength results, the rate of increase in the flexural strength with time decreased as the TWW replacement ratio increased, owing to the reaction of sulfate ions in TWW with Ca(OH) 2 and C 3 A, which disintegrated concrete matrix [83]. ...
... By contrast, Fig. 10(i) shows that mix T100-F0-C3 had higher amounts of silica and calcium than mixes T0-F0-C3 and T100-F0-C0, owing to the formation of calcium monosulphoaluminate hydrate (i.e., C 4 ASH 12 ) [84]. Furthermore, Fig. 10(j) shows that mix T100-F20-C3 reported lower calcium atoms and higher silica than mix T100-F0-C3 because of the pozzolanic reactions between FA and Ca(OH) 2 [83]. ...
Article
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The drastic increase in freshwater and ordinary Portland cement (OPC) consumption poses severe environmental and economic challenges worldwide. This study; therefore, explores the mechanical and durability properties of concrete incorporating treated domestic wastewater (TWW), class F fly ash (FA), and calcium nitrite-based corrosion inhibitor (CN). OPC paste and mortar with TWW were first prepared and compared with the permissible limits specified in ASTM C1602/C1602M − 18 provisions. After that, ten concrete mixes were prepared with different ratios of TWW (0%, 25%, 50%, and 100%), FA (0%, 20%, and 35%), and CN (0% and 3%) and tested for fresh slump and density, compressive and flexural strengths, electrical resistivity, porosity, and chloride permeability. All concrete specimens were cured with fresh water. Concrete hardened properties were tested at 7, 28, and 90 days. Test results revealed that TWW slightly decreased concrete compressive and flexural strengths by 5%–12%, whereas it dramatically increased the porosity and chloride permeability by about 40%. It was also shown that the addition of FA significantly decreased the chloride permeability of TWW concrete by 55%–71%. The optimum FA replacement ratio was observed at 20 wt%. The addition of CN was shown to deteriorate the strength and durability properties of freshwater concrete by 10%–39%. However, combining TWW and CN has improved concrete resistivity, porosity, chloride permeability by 32%, 28%, and 32%, respectively. The optimum concrete properties were obtained using 20 wt% FA and 0% CN. The obtained results were analytically supported by scanning electron microscopy (SEM), energy-dispersive X-ray microanalysis (EDX), and X-ray diffraction (XRD) tests. Moreover, Pearson correlation and linear regressions were performed on the experimental data.
... SF is a highly reactive pozzolanic reaction because of its high surface area, as shown in Table 1. SF reacts with calcium hydroxide from the cement's hydration to form new calcium silicate hydrates and consequently improves the mechanical properties and durability of concrete [21,22]. Additionally, SF can fill the voids between cement and aggregate particles and produce a dense matrix by enhancing the packing density of the concrete [23,24]. ...
... SF is a highly reactive pozzolanic reaction because of its high surface area. SF reacts with calcium hydroxide from the cement's hydration to form new calcium silicate hydrates and consequently improves the mechanical properties and durability of concrete [21,22]. Additionally, SF can fill the voids between cement and aggregate particles and produce a dense matrix by enhancing the packing density of the concrete [24,39]. ...
... Sulfat juga umumnya terkandung dalam tanah dan air laut (Vedalakshmi et al., 2005;Whittaker and Black, 2015). Degradasi beton akibat external sulfate attack terdiri dari physical sulfate attack, yaitu pengendapan garam sulfat dalam pori beton, dan chemical sulfate attack, yaitu masuknya ion sulfat ke matriks semen (Whittaker and Black, 2015;Panesar, 2019). Ion sulfat bereaksi dengan kalsium hidroksida dan kalsium aluminat hidrat untuk membentuk gypsum dan ettringite. ...
... Pertama, hydration expansion product dan kristal sulfat mulai menekan pori, menyebabkan ekspansi beton dan microcracking. Kedua, serangan sulfat menyebabkan dekalsifikasi C-S-H akibat terjadinya leaching senyawa kalsium (Whittaker and Black, 2015;Panesar, 2019 Tren kekuatan yang terus menurun menunjukkan proses hidrasi terhenti dengan paksa dan deteriorasi telah terjadi sejak awal spesimen terpapar lingkungan sulfat. Dapat disimpulkan bahwa setelah melewati batas tertentu, penambahan GGBFS tidak meningkatkan ketahanan beton melawan serangan sulfat. ...
Article
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Serangan sulfat (sulfate attack) termasuk hal yang umum terjadi pada struktur beton, mengingat ion sulfat banyak dijumpai pada tanah, air tanah dan air laut. Peningkatan ketahanan beton melawan sulfat akan berdampak besar pada durabilitas dan umur layan struktur beton. Penambahan supplementary cementitious materials seperti GGBFS (ground granulated blast furnace slag) ke campuran beton telah terbukti memberikan pengaruh positif terhadap durabilitas dan properti mekanis beton. Namun, GGBFS tergolong material yang baru dikembangkan di Indonesia dan potensinya dalam meningkatkan durabilitas beton belum dimanfaatkan secara luas. Berdasarkan hal tersebut, perlu dilakukan investigasi terkait aplikasi GGBFS dan pengaruhnya terhadap durabilitas beton, terutama dalam melawan serangan sulfat. Dalam studi ini, durabilitas beton dengan persentase penggantian GGBFS 30%, 50% dan 70% terhadap total volume binder dievaluasi menggunakan perlakuan siklus basah-kering dalam larutan magnesium sulfat. Tingkat degradasi beton diukur dengan melakukan observasi terhadap perubahan kuat tekan dan massa spesimen akibat serangan sulfat. Hasil penelitian menunjukkan bahwa penggantian GGBFS hingga 50% dari total volume binder dapat meningkatkan ketahanan beton terhadap serangan sulfat, ditunjukkan dengan kehilangan massa dan reduksi kekuatan yang lebih rendah dibandingkan spesimen kontrol dengan 100% semen Portland.
... Liapor is chemically stable and is a great alternative aggregate because of its low density (0.5 g/cm 3 ) and thermal conductivity (0.11 W/m·K). Silica fume is a by-product of the production of elemental silicon or alloys containi silicon in electric arc furnaces [16]. Silica fume significantly improves the over compressive strength and bond strength of the geopolymer composites [4,17,18]. ...
... Instead, the hollow ceramic microsphere (Elite Industrial, manufacturer, city, China) has a range particle size of 0.037 to 0.425 mm, a density of 0.35 to 0.45 g/cm 3 , and a thermal conductivity of 0.11 W/m·K. Silica fume is a by-product of the production of elemental silicon or alloys containing silicon in electric arc furnaces [16]. Silica fume significantly improves the overall compressive strength and bond strength of the geopolymer composites [4,17,18]. ...
Article
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The article presents preliminary results in studying reinforced and light-weight geopolymers, which can be employed in buildings, especially for walling. Such materials are very promising for the construction industry having great potential due to their favorable properties such as high mechanical strengths, low thermal conductivity, and low density. Moreover, they also exhibit several advantages from an economic and ecological point of view. The present study exanimated the use of specific fillers for the metakaolin-based light-weight geopolymers, emphasizing the above-mentioned physical properties. This research also investigated the electromagnetic shielding ability of the carbon grid built into the light-weight geopolymer structure. According to the study, the most suitable materials to be used as fillers are polystyrenes, along with hollow ceramic microsphere and Liapor. The polystyrene geopolymer (GPP) achieves five times lower thermal conductivity compared to cement concretes, which means five times lower heat loss by conduction. Furthermore, GPP is 28% lighter than the standard geopolymer composite. Although the achieved flexural strength of GPP is high enough, the compressive strength of GPP is only 12 MPa. This can be seen as a compromise of using polystyrene as a filler. At the same time, the results indicate that Liapor and hollow ceramic microsphere are also suitable fillers. They led to better mechanical strengths of geopolymer composites but also heavier and higher thermal conductivity compared to GPP. The results further show that the carbon grid not only enhances the mechanical performances of the geopolymer composites but also reduces the electromagnetic field. Carbon grids with grid sizes of 10 mm × 15 mm and 21 mm × 21 mm can reduce around 60% of the Wi-Fi emissions when 2 m away from the signal transmitter. Moreover, the Wi-Fi emission was blocked when the signal transmitter was at a distance of 6 m.
... The incorporation of WMP in concrete can cause a cement dilution effect, and consequently, optimizing the rate of WMP incorporation in concrete mixtures has paramount importance [79]. When used at low dosages, WMP does not seem to significantly alter the nature of cement hydration reactions [17]. ...
... When used at low dosages, WMP does not seem to significantly alter the nature of cement hydration reactions [17]. Nonetheless, its fine particles act as a microfiller and provide nucleation sites for the growth of hydration products, thus accelerating the kinetics of hydrations and resulting in higher CS at early ages [79,80]. When a high content of tricalcium aluminate (C 3 A) is present in the cement composition, the formation of calcium carboaluminates due to the hydration of C 3 A and calcium carbonate (calcite) could provide further early-age strength gain. ...
Article
In recent years, the volume of waste marble powder (WMP) from ornamental stone factories has increased rapidly, causing environmental concerns of soil, water and air pollution. While some studies have explored the benefits of incorporating WMP in concrete mixtures, the lack of pertinent data and a comprehensive understanding of how WMP influences the engineering properties of concrete has hindered the large-scale applications of WMP in the concrete industry. Therefore, this study examines the capability of machine learning (ML) to model the compressive strength (CS) of concrete incorporating WMP since it is the most specified property of concrete. WMP can improve the performance of concrete mainly owing to a physical microfiller effect and providing preferential sites for the nucleation and growth of early-age cement hydration products. However, considering that the pozzolanic reactivity of WMP is insignificant as demonstrated by phase composition and thermogravimetric results, its incorporation rate in concrete mixtures should be limited to a specific dosage, which can be optimized using ML techniques. ML modelling results showed that the CS of WMP concrete could be predicted with high accuracy (R 2 > 0.97) using extreme gradient boosting (XGB) and artificial neural networks (ANN) informational models, with ANN being more sensitive to the content of WMP. The feature importance results, with multicollinearity consideration, showed that the role of WMP in strength development could be mainly limited to 10-20% due to its inert nature.
... SF is a highly reactive pozzolanic reaction because of its high surface area, as shown in Table 1. SF reacts with calcium hydroxide from the cement's hydration to form new calcium silicate hydrates and consequently improves the mechanical properties and durability of concrete [21,22]. Additionally, SF can fill the voids between cement and aggregate particles and produce a dense matrix by enhancing the packing density of the concrete [23,24]. ...
... SF is a highly reactive pozzolanic reaction because of its high surface area. SF reacts with calcium hydroxide from the cement's hydration to form new calcium silicate hydrates and consequently improves the mechanical properties and durability of concrete [21,22]. Additionally, SF can fill the voids between cement and aggregate particles and produce a dense matrix by enhancing the packing density of the concrete [24,39]. ...
Conference Paper
Concrete is the most consumed material after water, and it is responsible for 10% of total CO2 emissions worldwide. Supplementary cementitious materials, including fly ash, silica fume, and granulated furnace slag, have been utilized to improve the mechanical and durability of concrete and reduce Portland cement consumptions. The paper aims to explore the effect of the supplementary cementitious materials' replacement on concrete foundation properties. It was found that fly ash significantly improved durability properties and workability. However, it delays the initial time setting and early compressive strength enhancements. At the same time, silica fume decreased concrete permeability and enhanced compressive strength. The incorporation of 15% silica fume can enhance the compressive by 21% compared to control concrete. On the other hand, silica fume can decrease workability remarkably.
... Similarly, a detailed review on the use of waste glass in concrete was provided by Siddika et al. [12]. Numerous supplementary cementitious materials (SCMs) have been used in concrete to control the ASR including metakaolin, fly ash, silica fume, and slag produced from blast furnaces [12][13][14][15][16]. However, the use of ternary blends that incorporate cement and waste products requires further exploration. ...
... A similar plateau effect was reported with the highest compressive strength achieved at 20% waste glass and 5% RHA. The increase in the compressive strength may be attributed to the correct proportion of silica from the RHA and SF with the calcium hydroxide of hydrated cement to make calcium silicate hydrate [16]. Similarly, an increase in compressive strength when incorporating RHA may also be attributed to the filler effect. ...
Article
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Although the disposal of waste ashes causes environmental hazards, recycling them helps in reducing their harmful impacts and improves the characteristics of building materials. The present study explores the possible use of locally available waste ashes including Rice husk ash (RHA)and Silica Fumes (SF) as a partial replacement for cement in concrete to counter the negative impact of alkali-silica reactions (ASRs). In the present study, ternary blends including RHA (0–30%), SF (5% and 10%) and Portland cement were investigated. The amorphous behavior of RHA and SF was confirmed by conducting an X-ray diffraction analysis. A petrography analysis was carried out to ensure the reactive nature of aggregates used to prepare the concrete specimen. Accelerated mortar bar tests were performed in accordance with ASTM C 1260 for up to 90 days. It was revealed that specimens incorporating a ternary blend of SF, RHA, and Portland cement exhibited less expansion compared to the control specimens without SF and RHA. The incorporation of 5% SF along with 20% RHA exhibited a 0.13% expansion at 28 days and 10% SF, along with 5% RHA which exhibited 0.18% expansion at 28 days which is within the range specified by ASTM C 1260, with the lowest compromise of the mechanical properties of concrete. Thus, the utilization of SF and RHA in the partial replacement of cement in concrete may be considered a practical approach to mitigate ASR effects as well as to reduce the environmental burden.
... Advantages: Improved workability, increased cohesiveness, reduced water demand. Disadvantages: Poor water absorption, low mechanical resistance at first aging [68]. ...
... Advantages: Reduced bleeding and segregation. Disadvantages: In some cases poor workability and consistency [68]. ...
Article
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Nanotechnology has emerged as a field with promising applications in building materials. Nanotechnology-based mortars are examples of such building materials that have widespread applications in the construction industry. The main nanomaterials used in mortars include nano-silica, nano-magnesium oxide, nano-alumina, nano-titanium oxide, nano-zinc oxide, nano-clay, and nano-carbon. This review paper presents a summary of the properties and effects of these nanomaterials on cement mortar in terms of its fresh-state and hard-state properties. The fresh-state properties include the setting time, consistency, and workability, while the hard-state properties include mechanical properties such as compressive, flexural, tensile strengths, as well as the elasticity modulus, in addition to durability properties such as water absorption, shrinkage strain, strength loss due to freeze–thaw cycles, and chloride penetration, among others. Different nanomaterials cause different physical and chemical alterations within the microstructures of cement mortar. Therefore, the microstructural characterization and densification of mortar are discussed in detail at varying temperatures. In general, the involvement of nanomaterials in cement mortar influences the fresh-state properties, enhances the mechanical properties, and impacts the durability properties, while reducing the porosity present in the mortar matrix. Cementitious nanomaterials can create a pathway for the easy injection of binding materials into the internal microstructures of a hydration gel to impact the hydration process at different rates, whereas their non-cementitious counterparts can act as fillers. Furthermore, the research gaps and future outlook regarding the application of nanomaterials in mortar are discussed.
... SCMs are environmentally friendly and can improve basic concrete properties. Concrete that contains SCMs exhibits a higher resistance to chloride ingress, the alkali-silica reaction, freeze-thaw damage, and sulfate attack [1]. Rahla et al. [2] investigated binary concrete blends containing fly ash, ground granulated blast-furnace slag, and silica fume. ...
... Zeolitic by-product − H3O + + nNH4 + = Zeolitic by-product − nNH4 + + H3O (1) where H represents exchangeable ions in zeolite and n is the number of electric charges [32]. Low substitutions (0.5-3 wt %) of OPC with the zeolitic by-product slightly accelerated the hydration process. ...
Article
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Fluid catalytic cracking (FCC) catalysts, used in the petroleum industry, are sources of zeolitic by-products. These by-products are often used as sorbents for the removal of ammonium ions from wastewater. After a period of use, the zeolitic by-product loses its sorption properties and is no longer effective. The problem is the use of zeolitic by-product with ammonium ions. In this study, a zeolitic by-product containing ammonium ions and high contents of active SiO2 and Al2O3 was used as a supplementary cementitious material (SCM). Cement pastes containing 0.5%, 1%, 3%, 5%, and 10% of the by-product were prepared, and the compressive strength and density of the pastes were evaluated. Incorporation of the zeolitic by-product increased the cement strength by 17% and 32% after 7 and 28 days of hydration, respectively. Thus, incorporation of the zeolitic by-product with ammonium ions as an SCM has a complex effect on an ordinary Portland cement (OPC) system. Ammonium chloride accelerated cement setting after 7 days of hydration, and the pozzolanic reaction positively affected strength development after 28 days of hydration. The reaction products caused the cement to have a compact microstructure. The zeolitic by-product containing absorbed ammonium ions can be successfully reused to replace ordinary Portland cement in cement pastes.
... Can the RAC properties improve with the addition of steel fibres, or not? Fly ash (left) and silica fume (right) supplement materials [1] [2] Silica fume is a by-product in the processing of simple silicone or silicone alloys in electric arc furnaces. The reduction of high pure quartz into silicone at a temperature of about 2000 °C creates silicone dioxide vapor that changes its physical state and becomes silica smoke at low temperatures. ...
... Silica fumes have a solid surface and extremely fine average size 0.1-0.3 μm [1]. The early slump of fresh concrete is to be raised to improve the workability. ...
Article
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If all concrete is to be recycled in a future scenario, recycled concrete will be needed. Usually concrete recycling causes loss of properties, but this does not have to be truth for all the mixtures. This paper shows a comprehensive knowledge about the improving methods used to keep the properties of the recycled aggregate concrete (RAC). In the reviewed literature several kinds of RAC were tested with various replacement ratios. The effect of adding steel fibres, silica fume or fly ash to the mixture were also examined both separately and together. Most of the experiments demonstrated excellent mechanical properties of the RAC compared with ordinary concretes. Based on these results the ideal RAC composition can be deduced and a future can be imagined when concrete can be recycled multiple times (MRAC).
... Hence, other novel approaches that have been tried to deal with this by-product are following the reuse or recycle pathways. In the field of civil engineering, steel slag has been reused as an aggregate supplement for concrete and cement production for road construction, backfill, earth cover, and embankment [4][5][6]. Regarding wastewater remediation, steel slag has been investigated for its adsorption capacity towards dyes, phosphate, nitrate, and ammonia [7 -11]. Cheng et al. concluded in their study that salicylic acid-methanol modified steel slag achieved an adsorption capacity of 41.62 mg/g for methylene blue via chemical adsorption [8]. ...
... The results showed that NaOH modification had a positive effect on the COD adsorption capacity of steel slag. According to the batch results, the suitable conditions for the COD adsorption on slag-based adsorbent included neutral pH (6)(7)(8), contact time of 90 minutes, adsorbent dosage of 10 g/L, and initial COD concentration of 400 to 500 mg/L. The COD adsorption on NS was better fitted with the Langmuir isotherm (R 2 = 0.997) than the Freundlich isotherm (R 2 = 0.833) while MS20 showed good agreement with both models (R 2 = 0.995 and 0.921 for Langmuir and Freundlich, respectively). ...
Article
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This study aims to characterize and investigate steel slag for the removal of its persistent organic pollutants (measured as COD) from pulp mill wastewater. Steel slag and its NaOH-modified states were characterized by Fourier-transform infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller (BET) surface area analysis, Barrett-Joyner-Halenda (BJH) pore size, and volume analysis. Batch adsorption experiments were conducted to investigate the COD adsorption of slag-based adsorbents. The modification of NaOH was found to improve the COD adsorption capacity (by 1.5 times) of steel slag by generating hydroxyl and carboxyl groups and enlarging the specific surface area and pore size in the steel slag particles. In batch experiments, the suitable conditions for COD adsorption on NS (steel slag) and MS20 (2 M NaOH-modified steel slag) were determined to be pH 6-8, contact time 90 minutes, and adsorbent dosage 20 g/L. Langmuir and Freundlich adsorption isotherm models satisfactorily described the adsorption of COD on both NS and MS20 with a good correlation. According to the Langmuir isotherm, the maximum COD adsorption capacity of NS and MS20 were 5.16 and 6.87 mg/g, respectively. Column experiments demonstrated that NS and MS20 had promising potential for COD treatment in pulp mill effluent. According to the column results, 20 g of NS or MS20 was able to keep 300 mL or 525 mL of 125 mg/L COD wastewater, respectively, reaching the threshold of the National Technical Regulation on Industrial Wastewater QCVN 40:2021/BTNMT.
... Additionally, the formation of ettringite causes an increase in the volume of the cementitious matrix and induces some micro cracks. Subsequently, the expansion and microcracks could lead to the strength reduction [40][41]. An increase in the densification of the matrix within the POBC mortar incorporating the RHA and CB supplements could contributed to the pore refinements and reduction of the connectivity of pores, which in turn mitigates the deterioration from the penetration of the dissoluble sulphate salt into the matrix. ...
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The utilization of local waste by-products as a building material has attracted great attention for an environmental sustainability and become a fundamental part of sustainable construction. In this experimental research, the local palm oil industrial waste and agricultural waste are utilized for the green mortar production. To examine the compres-sive strength and the durability performance of the green mortar mixtures, Palm oil boiler clinker (POBC) was used as a substitution material for natural fine aggregate. An ordinary Portland cement was partially replaced by rice husk ash (RHA) and calcium bentonite (CB) in the proportion of 10%, 20%, and 30% by weight of cement. The compressive strength, water absorption, porosity, durability against sulphuric acid and sodium sulphate attacks, and microstruc-tures of the POBC mortar mixtures were evaluated at the curing age of 7, 28, and 56 days. The experimental results revealed that the compressive strength, water absorption, porosity, and durability characteristics of POBC mortar incorporating RHA and CB were improved by long-term curing. Particularly, the 56-day POBC mortar incorporating up to 30% of RHA and 10% of CB yielded the superior durability against sulphuric acid and sodium sulphate attacks. Key words: palm oil boiler clinker, rice husk ash, calcium bentonite, compressive strength, durability against sulphuric acid and sodium sulphate attacks *danupon.t@psu.ac.th
... Granulated blast furnace slag is a kind of by product that occurs during iron production. The chemical structure, glassy phase content, fineness, and particle size distribution of the slag may be variable depending on the raw material source, the impurity degree and the iron production process [114]. The use of slags having different physical and chemical structures in concrete mixtures changes the workability of the mixtures. ...
Article
Adsorption of polycarboxylateether-based water-reducing admixtures (PCE) on the cement surface affects many properties of cementitious systems, especially fluidity. One of the most important parameters affecting the adsorption behavior of PCE is the anionic group properties. Therefore, understanding the anionic group properties of PCE is of great importance for cement-admixture compatibility. In this study, the effects of PCE's anionic group variation and cement properties on cement-admixture compatibility, especially adsorption, were reviewed based on the studies conducted in the literature. It was observed that phosphate and organo-silane substituted PCEs at certain rates have a positive influence on the fresh state properties of cementitious systems due to adsorption improvement and sulfate resistance. In addition, the fresh state properties of the cementitious system were negatively affected as the C 3 A content and the increment in fineness of the cement increased the admixture requirement. It was emphasized that the effect of pozzolan utilization on the adsorption properties of PCE in cementitious systems should be considered. Information was given about the properties of PCE recommended for use in the presence of pozzolan.
... Silica fume is one such category of microscale filler that has its origin from the electric arc furnace during the process of smelting for the production of silicon and ferrosilicon alloys. It is a pozzolanic material [13]. Generally regarded as waste, these silica fume particles have nowadays finding increased usage as fillers in concrete [14,15]. ...
Article
Silica fume, a by-product obtained during the smelting process of silicon and ferrosilicon alloys, is widely used as a filler material in concrete for construction purposes. This study discusses the use of silica fume (1–7% v/v) as novel fillers in epoxy glass microballoon syntactic foams. The total filler loading i.e. glass microballoons and silica fume is maintained at 40% (v/v). Epoxy syntactic foams are popularly being used in the construction industry for the fabrication of light-weight materials in the sandwiched configuration. The use of silica fume is expected to improve the mechanical properties of such syntactic foams, which otherwise suffer due to the incorporation of hollow glass microballoons. As expected, the incorporation of silica fume enhanced the mechanical properties of the base syntactic foam. Epoxy glass microballoons reinforced with silica fume (5% v/v) increased the specific tensile strength by ∼ 47 percent, flexural strength by ∼ 54 percent and compressive toughness by ∼ 23 percent, etc. The increase in properties is attributed to the homogenous dispersion of the silica fume throughout the matrix and the load-bearing ability of silica fume. The use of silica fume opens up vistas in the field of polymer syntactic foams.
... GGBFS is one of the most commonly used precursors in AAMs mainly due to its rich sources of Ca 2+ and Mg 2+ . The production of GGBFS is estimated to be around [113] 300 million tons annually [115] which promises a steadily available silica-rich material with low cost. GGBFS is generally consisted of SiO 2 , CaO, Al 2 O 3 , and MgO, with almost the same composition as in metakaolin with different ratio and much more availability. ...
Article
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IntroductionThe vast increase in CO2 and waste generation in recent decades has been a major obstacle to sustainable development and sustainability. In construction industry, the production of ordinary Portland cement is a major greenhouse gas emitter with almost 8% of total CO2 production in the world. To address this, Alkali-activated materials and geopolymer have more recently been introduced as a green and sustainable alternative of ordinary Portland cement with significantly lowered environmental footprints. Their use to replace Portland cement products generally leads to vast energy and virgin materials savings resulting in a sustainable concrete production. In doing so, it reuses the solid waste generated in industrial and manufacturing sectors, which is aligned with circular economy. In turn, it reduces the need for ordinary Portland cement consumption and its subsequent CO2 generation.Objective To provide further insight and address the challenges facing the substitution of ordinary Portland cement, this article reviews different types, mechanisms, and result of mechanical and durability properties of alkali-activated materials and geopolymer reported in literature. Finally, it discusses future projections of waste materials that have cementitious properties and can replace ordinary Portland cement and be used in alkali-activated materials and geopolymer.Graphical abstract
... Calcium chloride, obtained by treating oyster shells with hydrochloric acid, can accelerate the setting and hardening of concrete but its chloride ions can also corrode reinforcing steel inside the matrix (Montemor et al. 2003;Myrdal 2007). Sulfate, a hydration product of sulfuric acid, can react with the calcium hydroxide and calcium aluminate present in a concrete matrix to form secondary ettringite and gypsum, which can lead to expansion, cracking, and strength reduction (Panesar 2019). Calcium acetate had a positive effect on Brazilian splitting tensile strength and the uniaxial compressive strength of mortar (Zhang et al. 2015). ...
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Bio-concrete using bacterially produced calcium carbonate can repair microcracks but is still relatively expensive due to the addition of bacteria, nutrients, and calcium sources. Agricultural by-products and oyster shells were used to produce economical bio-concrete. Sesame meal was the optimal agricultural by-product for low-cost spore production of the alkaliphilic Bacillus miscanthi strain AK13. Transcriptomic dataset was utilized to compare the gene expressions of AK13 strain under neutral and alkaline conditions, which suggested that NaCl and riboflavin could be chosen as growth-promoting factors at alkaline pH. The optimal levels of sesame meal, NaCl, and riboflavin were induced with the central composite design to create an economical medium, in which AK13 strain formed more spores with less price than in commercial sporulation medium. Calcium nitrate obtained from nitric acid treatment of oyster shell powder increased the initial compressive strength of cement mortar. Non-ureolytic calcium carbonate precipitation by AK13 using oyster shell-derived calcium ions was verified by energy-dispersive X-ray spectroscopy and X-ray diffraction analysis. Stereomicroscope and field emission scanning electron microscopy confirmed that oyster shell-derived calcium ions, along with soybean meal-solution, increased the bacterial survival and calcium carbonate precipitation inside mortar cracks. These data suggest the possibility of commercializing bacterial self-healing concrete with economical substitutes for culture medium, growth nutrient, and calcium sources.
... Additionally, the formation of ettringite causes an increase in the volume of the cementitious matrix and induces some micro cracks. Subsequently, the expansion and microcracks could lead to the strength reduction [40][41]. An increase in the densification of the matrix within the POBC mortar incorporating the RHA and CB supplements could contributed to the pore refinements and reduction of the connectivity of pores, which in turn mitigates the deterioration from the penetration of the dissoluble sulphate salt into the matrix. ...
Article
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The utilization of local waste by-products as a building material has attracted great attention for an environmental sustainability and become a fundamental part of sustainable construction. In this experimental research, the local palm oil industrial waste and agricultural waste are utilized for the green mortar production. To examine the compressive strength and the durability performance of the green mortar mixtures, Palm oil boiler clinker (POBC) was used as a substitution material for natural fine aggregate. An ordinary Portland cement was partially replaced by rice husk ash (RHA) and calcium bentonite (CB) in the proportion of 10%, 20%, and 30% by weight of cement. The compressive strength, water absorption, porosity, durability against sulphuric acid and sodium sulphate solutions, and microstructures of the POBC mortar mixtures were evaluated at the curing age of 7, 28, and 56 days. The experimental results revealed that the compressive strength, the water absorption, the porosity, and the durability characteristic of POBC mortar incorporating rice husk ash and calcium bentonite were improved by long-term curing. Furthermore, the 56-day’s POBC mortar incorporating up to 30% of rice husk ash and 10% of calcium bentonite yielded the superior resistance to sulphuric acid and sodium sulphate attacks.
... In addition, RHA was a substitute material in the manufacture of refractories, ceramics, and insulating material. 8 Silica obtained from plant, coal ash, and geothermal mud is amorphous and more reactive due to hydroxyl groups (silanol, Si-OH). 9 Pre-treatment techniques of biomass using the oven heating method, soaking and washing using warm water, 10 alkaline metal hydroxides solutions such as NaOH 11 and KOH, 12 acid solution, 13 and ionic solvent. ...
Article
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Silica can obtain by utilizing rice husk (RH). This study uses NaOH leaching agents with temperature variations of 600, 700, 800, 900oC at burning RH. Rice husk ash (RHA) reacted with NaOH 10% at 90°C at 240 rpm for 2 h, then the addition of HCl until pH 7 and drying to become SiO2. Extracted silica characterization using FTIR showed silanol and siloxy groups, XRD showed that silica dominates by quartz and calcite, XRF showed components of SiO2 and Si. Variation temperatures of 600, 700, 800, 900oC at burning RH made different components SiO2 and Si. © 2021, Rasayan Journal of Chemistry, c/o Dr. Pratima Sharma. All rights reserved.
... The chemical effect is created by the pozzolanic reaction between SCM's amorphous silica with Ca(OH)2 generated by cement hydration [5,6], and/or by the hydraulic reaction of SCM itself, such GGBFS [7,8]. In addition, the partial replacement of cement by SCM filling the voids between cement particles would increase the packing density, then the strength and durability of concrete [3,[8][9][10]. ...
Article
The utilisation of supplementary cementitious materials (SCMs) is widespread in the concrete industry because of the performance benefits and economic. Ground granulated blast furnace slag (GGBFS) and fly ash (FA) have been used as the SCMs in concrete for reducing the weight of cement and improving durability properties. In this study, GGBFS at different cement replacement ratios of 0%, 20%, 40% and 60% by weight were used in fine-grained concrete. The ternary binders containing GGBFS and FA at cement replacement ratio of 60% by weight have also evaluated. Flexural and compressive strength test, rapid chloride permeability test and under-water abrasion test were performed. Experimental results show that the increase in concrete strength with GGBFS contents from 20% to 40% but at a higher period of maturity (56 days and more). The chloride permeability the under-water abrasion reduced with the increasing cement replacement by GGBFS or a combination of GGBFS and FA
... Silica fume (SF) is a by-product derived from the smelting process in manufacturing silicon and ferrosilicon alloys. Reduction of high-purity quartz to silicon in an electric arc furnace at temperatures as high as 2000 °C yields silicon dioxide vapor which oxidizes and precipitates at lower temperatures to form SF. The fine particle size and high amorphous SiO 2 content (ranging between 85 -90 %) render SF as a highly reactive pozzolan [Siddique and Mehta, 2020;Panesar, 2019]. Incorporating SF as a pozzolan in PC systems is reported to enhance strength and durability characteristics owing to its compact microstructure [Siddique, 2011]. ...
Article
Synthetic activators used in alkali-activated binder are the primary contributors to its adverse environmental effects. Therefore, this study aims to perform a life cycle assessment of alkali-activated mortar (AAM) prepared from industrial waste as precursors and activators. The impact analysis is performed through ReCiPe methodology for six different AAM mixes. Environmental impacts of replacing conventional precursors (fly ash and slag) with waste ceramic powder (WCP) and red mud (RM) and conventional activators (sodium silicate (SS) and sodium hydroxide (SH)) with RM, desulfurization dust, and silica fume are assessed. The efficiency of ReCiPe is compared with recommendations from the International Reference Life Cycle Data System. Sensitivity analysis for SH produced using three different techniques and simplified cost analysis for the mortar mixes is conducted. SS is observed to contribute 50–59% of climate change for mixes with conventional activator combination. WCP as a precursor warrants higher dosage of SS and SH, thereby increasing the environmental impact. Replacing SS with silica fume has the least negative effects on ecosystem quality and human health. AAM prepared with conventional activators shows lower resource depletion due to a lower dosage of activators and the absence of pretreatment of fly ash. ReCiPe can be used to evaluate all the impact categories except freshwater ecotoxicity and human toxicity, for which USEtox is suggested. Sensitivity analysis shows that the membrane cell process of SH production is eco-efficient. Savings of up to 14% are observed by replacing both precursors and activators with industrial residues.
... As a result, alternative approaches to the problem are switching toward reuse and recycling pathways. In the field of civil engineering, there are many attempts to use steel slags as additives for concrete or cement for road construction, backfill, earth cover, and embankment [3][4][5]. With the main chemical composition including various metal oxides, adsorption is also considered a promising recycling pathway for steel slag [6,7]. ...
Article
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Steel slag (SS) and Blast-furnace slag (BFS) are massively generated each year as by-products and regarded as hazardous solid waste from the steel manufacturing industry. This study focused on using the modified SS (MS20) and BFS (A-BFS3), which were inherited from previous research, in a fixed-bed column for continuous removal of ammonium and COD from the landfill leachate. The MS20 adsorbent was obtained from mixing the steel slag with NaOH 2M while the A-BFS3 was synthesized by acidic activation of the blast-furnace slag with HNO 3 3M. Both materials were characterized Fourier-transform infrared spectroscopy (FT-IR), Brunauer-Emmet-Teller (BET), and Barrett-Joyner-Halenda (BJH). The experiment was performed under variation of liquid flow rate and empty bed contact time (EBCT) to determine its correlation with the breakthrough time to meet the COD and ammonium standards for leachate effluent. Thomas and Yoon-Nelson models were also fitted with the experimental data for the examination of adsorption breakthrough behavior. The results indicated that the breakthrough adsorption capacity of COD and ammonium onto MS20 and A-BFS3 were 2.36 mg/g and 1.63 mg/g, respectively. The MS20 packed column was able to keep the COD concentration under the QCVN 25:2009/BTNMT column A standard value for 240 minutes with the liquid flow rate of 2.5 mL/min. Meanwhile, with a similar flow configuration, the A-BFS3 packed column maintained the ammonium concentration of ammonium in the output leachate to meet the standard for 480 minutes. The promising result for ammonium and COD adsorption could be achieved at higher EBCT.
... Additionally, 5% silica fume (SF) was used as part of a ternary blend with 35% HC fly ash. The HC fly ash had a CaO = 28.98% and is known to be susceptible to sulfate attack [6,7,[21][22][23]. The chemical composition of the cementitious materials, as well as the phase composition of the cements used is presented in Tables 1 and 2, respectively. ...
Article
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In this study, the performance of several binary and ternary mixtures containing high-calcium fly ash and other pozzolans, such as Class F fly ash and silica fume, were investigated for their sulfate resistance using different sodium sulfate solutions. The mortar bars were placed in a similar sulfate solution as per modified ASTM C 1012/1012M (33,800 ppm SO42−) with a less severe sulfate solution (6000 ppm SO42−) has been tested to resemble actual field performance for a duration of 18 months. The phase composition of the mortar samples was investigated using X-ray diffraction and scanning electron microscope coupled with energy dispersive spectroscopy (SEM/EDS). Results show that the mortar bars placed in the moderate sulfate concentration experience less expansion and deterioration than the same bars placed in the higher sulfate concentration. Storage in sodium sulfate solutions resulted in the formation of ettringite and gypsum in both sulfate concentrations. Replacement of cement by high-calcium fly ash showed significantly higher amounts of ettringite formation, especially for the mortar bars stored in the higher sulfate concentration. SEM analysis revealed ettringite to be the primary cause of disruption and deterioration observed in the mortar bars.
... SF has a solid surface and an extremely fine average size of 0.1-0.3 mm [1]. The early slump of fresh concrete should be increased to improve workability. ...
Article
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Cement replacement materials are commonly used in concrete technology. Several researchers have examined high-performance concrete after adding mineral admixtures to it, but further studies are still needed to provide the optimum dosage of these materials for instance fly ash and silica fume. This study compares three types of concrete and the mechanical properties (compressive strength, flexural strength, and splitting tensile) of these types at the age of 28 and 90 days. The test results designate that adding the mineral admixtures commonly affects the mechanical properties of all the tested types. However, silica fume is more operative than fly ash. Furthermore, adding the fly ash and silica fume in the same concrete type slightly improves the mechanical properties.
... SF is a co-product from the production of silicon, ferrosilicon, or zirconium in electric arc furnaces. The reduction of high-purity quartz to silicon generates silicon dioxide vapor that oxidizes at low temperatures and forms SF [134,135]. It is an extremely fine material consisting of amorphous SiO 2 particles with a degree of purity generally greater than 90% [136]. ...
Article
The construction industry is currently facing the great challenge of applying sustainable materials with suitable mechanical properties and durability performance. Among the different strategies used to meet technical and sustainable criteria, two interesting approaches can be highlighted: the reuse of materials to produce sustainable construction materials and the development of smart concretes for Structural Health Monitoring. The first strategy consists of using recycled materials, co-products, and by-products of industrial processes to replace primary raw materials used to produce blocks, ceramics, mortars, and concrete. The second strategy is associated with the development of multifunctional cementitious and alkali-activated concretes with strain and damage self-sensing properties in response to the growing concerns related to the increase in the durability of civil structures. This paper presents a critical review of previous studies that combine both strategies, i.e., research works investigating smart construction materials that incorporate recycled and waste materials and exhibit self-sensing properties. Sustainable self-sensing composites (SSCs) incorporating different types of recycled and waste materials were presented. These sustainable admixtures provided different benefits to self-sensing composites, such as improvements in the conductive path within the matrices and improvements in the dispersion of other conductive fillers. The effects of silica fume, fly ash, steel slag, red mud, and other recycled materials on the electrical resistivity, strain-sensing properties, and damage-detection properties of SSCs were discussed. Promising SSCs were identified based on comparisons between gauge factor, stress sensibility, linearity, strain amplitude, and stress amplitude of SSCs produced with one single type of waste or combination of various types of wastes. In this sense, SSCs were found to be a viable alternative for modernization and greater sustainability of the construction industry.
... However, gypsum crystal is formed in CAPHSC6 and its control groups due to the invasion of sulfate ions which filled the pores in the surface regions. Sulfate attack is attributed to the reaction between sulfate ions with CH and C 3 A to form gypsum and ettringite, subsequently resulting in expansion, cracking and mass loss [85]. Fig. 17 shows the XRD patterns of CAPHSC6 and its control groups exposed to Na 2 SO 4 solution (5 wt%) for 10 months. ...
Article
Supplementary cementitious materials (SCM) and alkali activated materials (AAM) are widely researched as alternative binder in concrete due to potential for reducing greenhouse gas emissions by utilizing industrial by-products. Phosphorus slag (PS) is the by-product of yellow phosphorus industry, which can partially substitute ordinary Portland cement (OPC) and reduce carbon footprint. This paper provides a comprehensive review of different activation methods (mechanical, thermal, chemical and alkali activation) to study the factors affecting the mechanical properties and underlying mechanism of PS as binder in SCM and precursor in AAM. The major drawback of PS in cement-based materials or concrete is the low early strength and long setting time due to the presence of P2O5, and this intensifies as the PS replacement amount increases. The mechanical activation by increasing the fineness, utilization of chemical activators and elevated curing temperature to improve the early-age performance of PS blended cement (PSC) are summarized. Specifically, the effect of these activation methods with different PS replacement level on cement paste, mortar or concrete are discussed in terms of compressive strength, setting time and microstructure. Combined activation gives the best outcome in improving early age properties of PSC. The composition of PS, replacement level and fineness of PS, curing temperature and method, type and dosage of activator are highlighted in this paper. Generally, the optimal PS replacement level is 30 – 40% in non-activated PSC, while activated PSC with proper activators can increase the PS replacement level to 35% – 80% or even fully replace OPC in AAM system.
... ASR is the result of chemical reactions among alkaline hydroxides (usually provided by the cement) with the available reactive silica in certain aggregates occurring in hardened concrete. Reactive aggregates can expand excessively, implying a progressive deterioration of the construction due to the formation of alkali-silica gel, resulting in expansion pressure exerted on the aggregates and concrete matrix (Panesar, 2019). ...
Article
This study evaluated characteristics of mortars using recycled construction and demolition waste (CDW) from the industry as fine recycled aggregate in replacement of natural sand (NS). Mixes with replacements in volume of 20 and 100% CDW and a control mix with just NS were tested for their compressive and flexural strength and alkali–silica reactivity (ASR). For mechanical strength, experimental results showed satisfactory performance for 20% CDW content. Concerning the ASR test, mortars with CDW performed better than the control, demonstrating a general innocuous behaviour for ASR. Scanning electron microscopy and energy-dispersive X-ray analysis were performed on aggregate and mortar samples before and after the ASR test and confirmed the results, demonstrating that the attack was more severe in the samples with the greatest amount of siliceous material in the aggregate. The results demonstrate the viability of the use of CDW fine aggregate replacement in mortars, envisaging the possibility of its incorporation in concrete.
... To be specific, sulfate in certain conditions reacts with cement compounds such as monosulfate, portlandite and C-S-H gel. The results of this reaction may be ettringite, gypsum, or thaumasite [10,11]. ...
Article
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Sulfate attack is one of the drawbacks of cementitious materials for stabilized soils. In the current study, a durability comparison of stabilized soil with cement (Type IV) and waste paper fly ash (WPFA) was conducted. First, the treated soil’s unconfined compressive strength (UCS) was tested. Next, the treated soil was subjected to various wetting/drying cycles with various sulfate concentrations and temperatures for a year. In the meantime, samples were taken for DRX, FTIR, and TGA microstructural analyses. Additionally, samples were manufactured to track swelling over an 800 day period. The outcomes show that WPFA’s UCS remained constant. Furthermore, ettringite development can be seen in the microstructural studies, however testing on linear displacement over 800 days revealed no significant changes in swelling. Finally, SEM was used to verify the ettringite formation at 360 days in order to confirm the previous findings. All the results indicated that stabilizing soil with 5% of WPFA and 3% of cement IV is possible even in presence of high sulfate concentrations, while maintaining the durability of the structure.
... In addition to acting as a filler material, silica fume could also be used as a highly effective pozzolanic material in enhancing mechanical resistance and durability of concrete. 27 The silica fume had its specific gravity of 2.3 and contained 95% SiO 2 , while the silica powder had its specific gravity of 2.6 and contained 98% SiO 2 . Table 2 presents the properties of four steel fiber types used in this paper while Figure 3 shows the photos of them. ...
Article
The mechanical behaviors and their correlations of ultra‐high‐performance fiber‐reinforced concretes (UHPFRCs) with various steel fiber types were highlighted in this investigation based on the experiment combined with sectional analysis. Under compression, five fiber types with 2.0 vol% were investigated as follows: no fibers (PL), long twisted fibers (LT), long hook fibers (LH), long smooth fibers (LS) and hybrid fibers (HB, 1% twisted blended with 1% short smooth fibers). The LT revealed the highest compressive strength and strain capacity whereas the PL exhibited the lowest ones. Compared to the PL, the HB produced significant enhancements in strength, elastic modulus and deformation capacity under compression, tension and bending. The order in effectiveness of strength enhancement owing to additional hybrid fibers was as follows: bending > tensile > compressive loading. Based on sectional analyses, the enhancements in moment resistance of UHPFRC beams were closely correlated with higher compressive strength and smaller compressive strain capacity. Besides, the condition for first cracking at the bottom of UHPFRC beam was explored. Finally, a simplified model, based on the tensile response of UHPFRCs, for predicting the flexural resistances of the UHPFRC beams was proposed and validated.
... In addition, researchers have used polymeric fibers for mitigating crack propagation due to frost-induced damage [14,15]. Each of these strategies is often deployed in conjunction with traditional air entrainment [16][17][18]. None of these methods prevent ice growth once ice nucleation has occurred. ...
Article
This work presents experimental evidence that specific molecular weights of poly(vinyl alcohol) (PVA), a molecule that displays biomimetic ice recrystallization inhibition (IRI) behavior, are required to impart freeze-thaw resistance to portland cement paste when PVA is added as a water-solubilized admixture. Three molecular weights of PVA were first tested for IRI activity. IRI-active PVA-modified cement pastes were then prepared and tested for freeze-thaw resistance. X-ray micro-computed tomography was employed to investigate internal damage and to characterize the air void system. Differential scanning calorimetry was used to quantify and compare the amount of ice that formed in the hardened pastes. Mercury intrusion porosimetry was used to characterize the pore-size distributions of cement pastes. Results substantiate that PVA with a molecular weights >31,000 g/mol can impart freeze-thaw resistance to cement paste and that the freeze-thaw enhancement is not due to improved hydrophobicity or an adequately entrained air void system. PVA additions did lead to reductions in porosity. However, the reductions were insufficient to fully explain why lower quantities of ice formed during freezing, indicating that IRI-active biomimetic polymers, like PVA, can enhance the freeze-thaw resistance of cement paste due, in part, to their interaction with ice.
... Sulfate attacks and alkali-silica reactions both cause expansion and thus cracking in concrete [41,42]. In contrast, drying shrinkage caused by loss of capillary water produces cracks due to shrinkage [43]. ...
Article
Full-text available
Concrete is the most widely used construction material. However, it cannot sustain the harsh environment and can easily deteriorate. It results in repair and reworks that amount to a considerable loss of money and time. The life span of concrete reduces if exposed to external attacks, for instance, sulfate attacks, alkali-silica reactions, corrosion, and drying shrinkage. These ubiquitous attacks cause a reduction in service life and raise the need for early repair and maintenance, resulting in higher life cycle costs and structural failures. To resolve these issues, the potential of styrene-butadiene-rubber (SBR) ultrafine powder as cement replacement polymeric admixture at 0%, 3%, 5%, 7%, and 10% have been evaluated. The effect of SBR-powder on concrete is investigated by conducting an alkali-silica reactivity test (ASR), rapid-chloride-permeability test (RCPT), drying shrinkage, and sulfate resistivity tests. Workability, compressive and flexural strength tests are also conducted. For ASR and drying shrinkage, mortar bar samples were cast, exposed to respective environments, and the percentage change in length was measured. For mechanical tests and RCPT, prisms, cylinders and cubes were cast and tested at 28 days. The SBR-powder modification reduces concrete’s permeability, drying shrinkage, and expansions due to ASR and sulfate attacks. SBR powder increased workability by 90%, compressive strength by 23%, and flexural strength by 9.4% in concrete when used at 10% cement replacement by weight. The SBR-powder (10%) modification reduced the RCPT value by up to one-third (67%), drying shrinkage by 53%, ASR by 57%, and sulfate reaction by 73%. Consequently, SBR powder usage can adequately improve the workability, mechanical properties, and durability of the concrete and lead to advanced sustainable concrete with low repair requirements.
... Consider the reaction to proceed according to the idealized equations represented by Equations 1 and 2. However, the ASR cannot proceed in a concrete specimen if the alkali concentration is less than a certain threshold value. [19][20][21][22] 4SiO 2 + 2NaOH → Na 2 Si 4 O 9 + H 2 O (1) 3SiO 2 + 2NaOH → Na 2 Si 3 O 7 + H 2 O ...
... Slags have been widely used to produce aggregate supplements for cement production and road pavement (Maharaj et al., 2017;Jiang et al., 2018;Lim et al., 2016;Wang et al., 2020). Panesar (2019) revealed that reusing slags in cement production, compared to conventional processes, can reduce CO 2 emissions by approximately 40% and decrease energy consumption. ...
Article
In modern steelmaking, multiple processes comprise a continuous manufacturing system, but not all phosphorus content data are connected or integrated into a holistic and systematic database. Disconnected data hinder the improvement of material management and resource efficiency in the industry. The objective of this study was to establish a method to evaluate material flows, reduce uncertainty, and perform quality control for waste recycling in the steelmaking industry. The results indicate that 10% of the phosphorus input is present in the final products, 30% accumulates in the slags, and more than 60% of the total mass remains in the processes. Comparing the material flow analysis results obtained using static and probabilistic approaches, the partition ratio of the phosphorus content in slags changes from 24.07% to 40.78%, but that in processes changes from 49.10% to 68.05%. This indicates that the variations in phosphorus content in slags and processes might affect the effectiveness of slag recycling and might increase the resource consumption required to maintain the quality of final products. The probability of forming substandard products in the baseline scenario is 0.43. Adopting a 50% removal rate, the probabilities of forming substandard products are reduced to 0.36 (waste removal scenario), 0.38 (slag reduction scenario), and 0.31 (raw material treatment scenario). The performance of raw material treatment and waste removal is more efficient for quality control. The method used in this study can be applied to evaluate the possible outcomes of waste recycling and reduce the probability of forming substandard products.
... XRF analyses showed a composi-151 tion of 55% SiO2, 40% Al2O3, and Fe2O3 and TiO2. This is in line with the results of 152 other studies (Velosa et al. 2009;Panesar, 2019) showing that the main constituents 153 of metakaolin are SiO2 and Al2O3 although the detailed composition might vary slightly 154 according to the specific sources of kaolin employed. The metakaolin is activated with 155 a highly alkaline water solution of potassium silicate (w(SiO2)/w(K2O) = 1). ...
Article
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An attractive approach to reduce the carbon footprint of deep soil mixing (DSM) is to replace Portland cement-based binders by geopolymers based on metakaolin. Safe design requires a good understanding of the mechanical and hydraulic properties of the improved ground but very little is known about metakaolin-soil mixtures. For instance, shrinkage during curing is a significant issue for metakaolin-based concretes but has not been previously studied in soilcretes. In this work the permeability and strength of sand and silty sand based metakaolin soilcretes are studied under different curing conditions. The development of microcracks induced by geopolymer shrinkage is confirmed through a microstructural study using mercury intrusion porosimetry, scanning electron microscopy and X-Ray computed tomography. The influence of microporosity and binder filling on permeability and strength is clarified adapting well-established soil models. A modified Kozeny-Carman formulation is proposed for permeability. A mixture ratio model is calibrated to represent strength. In general, the metakaolin stabilised materials present excellent mechanical and hydraulic properties, although these are very sensitive to curing conditions.
... SF, also known as micro-silica, is a largely amorphous form of silicon dioxide (SiO2), which contains extremely fine SiO 2 spherical particles of ( Fig. 2(b)) with a mean size of 0.1-0.3 μm (Panesar, 2019). ...
Article
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This paper provides a comprehensive review of the utilization of industrial wastes in 3D concrete printing processes. Concrete 3D printing processes are introduced, highlighting the need for unique material requirements. The literature on the different wastes that have been used for producing 3D printable mixtures is reviewed, including waste generation, material properties, and the roles of these materials in improving the fresh properties needed for concrete printing. Factors affecting successful utilization of these waste materials in 3D printable concrete are discussed in addition to their environmental impacts. This paper underlines the positive impacts of using industrial wastes for improving the sustainability of 3D printable concrete. It is expected that printable concrete formulations containing high volumes of industrial waste (and chemical admixtures) can be developed to improve the sustainability index of this emerging construction technique.
... In Table 1 can be observed that silica fume exhibit a higher diameter when compared to the usual mean size presented in the literature (from 0.1 to 0.3 µm) [38]. Usually, 10 µm agglomerates can be found in silica fume due to its high fineness [39]. ...
Article
Among the short-term viable alternatives for mitigating the direct emissions of carbon dioxide into the atmosphere by the cement industry, the partial replacement of Portland clinker or cement with supplementary cementitious materials (SCM) is the most efficient and conceives ecologically friendly binders. Limitations of available traditional SCMs create a demand for the exploration of alternative materials from by-products and wastes of other industries. As a result of the considerable variability in the properties between batches of these materials, it is necessary to use methods that allow the large-scale evaluation of SCMs in a fast, practical, reliable, and robust manner. This study presents the effects of increasing the curing temperature in the acceleration of the relative decrease in peak intensity (RDPI) test. The results show that samples cured at 65 °C after 3 days presented RDPI with a good indication of the reactivity level of the analyzed pozzolans. Additionally, strong correlations (R2 > 0.90) are obtained with compressive strength at 28 and 90 days. Thus, the RDPI test presents a potential for evaluating pozzolanic reactivity. However, further study is required on the SCM to CH ratio to avoid limiting the effectiveness of highly reactive pozzolans.
... Based on previous studies, the inclusion of SCMs in either form can reduce the environmental impact of the final concrete when it is viewed as a waste material. Yet, given that the production of major SCMs, such as coal fly ash, is a result of coal processing for electricity production, the actual life cycle assessment results show that the most common industrial by-products (such as coal fly ash, GGBFS, and silica fume), can, in fact, potentially increase the overall environmental impact of the respective concrete [192]. In general, however, the use of waste materials most commonly has a reduced environmental impact rate, compared to conventional materials. ...
Article
Full-text available
Due to constant growth of waste production, recent strategies in waste management such as circular economy promote the maximum life cycle use of materials. In construction industry where structures tend to last for decades, the use of such recycled materials can have numerous benefits including overall reduction in cost, in use of virgin materials, and in CO2 production as well as providing an opportunity for a tailored concrete with specific properties. Yet, because of the stereotypical and negative image of mechanical properties reduction, as a result of using waste materials, often their vast contribution in sustainability and durability properties are not taken into consideration. In this regard, we propose viewing waste materials as secondary raw materials that in certain regards, can provide a favorably tailored property. In this regard, the following review article first provides a short description of the most commonly used waste materials such as supplementary cemen-titious materials (fly ash, ground granulated blast furnace slag, silica fume, metakaolin, rice husk ash, municipal solid waste ash, steel slag, copper slag), ceramics from construction and demolition (glass powder, brick and tile ceramic and porcelain), and the vastly available plastic materials (polypropylene, polyethylene terephthalate, polyvinyl chloride, and rubber). Then, by reviewing a selected environmental impact (life cycle assessment), physicochemical, durability, and finally mechanical properties discuss the limitations, future projections of newer waste materials (e.g., agricultural waste) to be used and suggest potential future study in this area.
... Silica fume (SF) is a byproduct derived from the smelting process of silicon, and an alloy containing silicon in an electric arc furnace possesses an extremely fine spherical shape (1/100th of ordinary Portland cement), thus causing health and environmental issues upon dumping and mixing in an open atmosphere. However, its highly amorphous nature with enriched silicon dioxide makes it substantially pozzolanic [6]. The silicon dioxide reacts with the calcium hydroxide in the presence of water to produce calcium silicate hydrate gel, which is responsible for the strength improvement of problematic soil [7]. ...
Article
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Peat is a well-known problematic soil associated with poor engineering properties. Its replacement with an expensive competent foundation material is practiced for road embankment construction which is costly and causes greenhouse gas emissions. Therefore, this paper investigated the effectiveness of a byproduct from a metal industry (silica fume) to stabilize peat along with ordinary Portland cement (OPC) through a series of experimental tests. After peat-indexed characterization, a number of standard compaction and mechanical tests were performed on the stabilized and parent peat. For this purpose, nine designated mixes were prepared possessing various combinations of silica fume (SF) and 10–20% OPC. Unconfined compressive strength (UCS) and California Bearing Ratio (CBR) tests were carried out after 7, 14, and 28 days of curing to assess strength enhancement and binder effectiveness, and the microstructural evolution induced by the binders was examined with scanning electron microscopy (SEM). The analysis revealed a substantial improvement in mechanical properties with the incorporation of SF and OPC, ultimately meeting the minimum strength requirement for highway construction (i.e., 345 kPa). A peak UCS of 1063.94 kPa was recorded at 20% SF, and an unsoaked CBR value of 42.95 was observed using 15% SF and 15% OPC after 28 days of curing. Furthermore, the increasing percentage of hydraulic binders exhibited brittle, collapsible failure, while the microstructural study revealed the formation of a dense matrix with a refined pore structure in the treated peat. Finally, a significant statistical analysis was carried out by correlating the test parameters. In this way, rather than stockpiling and dumping, an industrial byproduct was implemented in peat stabilization in an eco-friendly manner.
Chapter
Concrete manufacturing is characterized by the production of large amounts of material, that is later transported to a building site, placed, and cured. Carbon nanotubes (CNTs) and carbon nanofibers (CNFs) can be added to concrete mixes, either as dry powders, or wet dispersions. Many production technologies remain rather primitive, and unfortunately, are not always suitable for the handling of nanomaterials in a safe and economically viable manner. This chapter will briefly describe the most commonly used concrete production methods and crucial aspects related to the safe handling of nanosized materials. Each production method has its advantages and disadvantages related to the process itself, and the subsequent performance of the fresh and hardened concrete. Both manual and mechanical mixing methods will be addressed. This will be followed by a comprehensive review of methods commonly used to incorporate CNTs and CNFs into concrete mixes. The chapter will close with a summary of key aspects that should be considered when producing large quantities of concretes containing nanomaterials.
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Pile foundations are the elements of structures used to carry and transmit the structures loads to the bearing ground located at some depth below ground surface. The aim of this paper is to explore the improvement of reinforced concrete piles, subjected to harsh marine environment, because of including supplementary cementitious materials, including fly ash and ground granulated furnace slag (GGFS). The overview showed that fly ash might be the optimum material to be included because it improved the workability, slump, hydration process, and it enhanced some mechanical properties such as compressive strength. The main improvement was in the durability properties. For instance, the permeability and void ratio was significantly improved as well as the internal microcracks were decreased as a results of initial temperature reduction of hydration process. Fly ash replacement ratio should be within a limit, 10-30%. Having a ratio more than these can delay the hydration process; hence, delaying the initial and final setting times. Incorporating ground granulated blast furnace slag was enhanced durability properties such as resistance to chemical at-tacks, chloride attacks, carbonation and it decreased water permeability of concrete.
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The use of supplementary cementitious materials (SCMs) has increased over the years due to the carbon footprint associated with the production of cement, which contributes to 10% of the total global CO 2 gas emissions. This causes an increase in global warming, and the exponential increase in demand for construction of concrete has caused depletion of natural resources. Furthermore, due to increased urbanisation, large quantities of agro-industrially processed waste materials are generated and dumped into landfills, causing significant land scarcity, environmental issues, and pollution. Therefore, it has become necessary to reduce the CO 2 emissions by reducing our dependency on cement as a binder and developing eco-friendly concrete using alternative binders from agro-industrial waste materials. This study utilises Rice Husk Ash (RHA) as SCM and reinforcing with polypropylene (PP) fibres. The cement content is replaced with 5 to 20% RHA with an increment of 5% while reinforcing with PP fibres ranging from 0.20 to 0.30%. Based upon the results, it can be observed that concrete incorporating 15% RHA and reinforced with 0.25% PP fibres achieved better performance than the specimen with no SCM. However, a further increase in RHA content decreased concrete strength, which could not be recovered entirely with the reinforcement of PP fibres, though concrete with higher (20%) RHA reinforced with PP fibres could be used for non-structural and low-cost construction.
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Supplementary Cementitious Materials (SCMs) market share in ready mix concrete industry has been significantly increasing during the past 2 decades. SCMs as silica fume, fly ash, quartz flour, and blast furnace slag are currently used in partial replacement of conventional portland cement to improve mix properties including flowing ability, compressive strength, modulus of elasticity, and long-term performance. The main advantages of SCMs are attributed to the contribution of SCMs to the formation of additional concrete binder and the improved packing order of the cementitious material matrix. Due to the afore-mentioned advantages, SCMs have been used in developing ultra-high-performance concrete, also known as reactive powder concrete. SCMs are successfully used in developing non-proprietary high-performance mixes used in high-rise construction and in fabricating high performance precast/prestressed bridge girders for new infrastructure projects. This paper displays the advantages of SCMs, and present different proprietary and non-proprietary mixes developed by incorporating SCMs, and their effect on different concrete properties. The wide spread of SCMs in concrete industry would potentially increase construction projects life span and minimize the need to routine maintenance.
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The rapid progress in the industrial development has increased the concern about the waste generated that may produce genuine environmental pollution. The use of supplementary cementitious materials (SCMs) from different sources may decrease a lot of non-renewable energy consumption. In this review, SCMs such as ground granulated blast furnace slag (GGBFS), fly ash (FA), silica fume (SF), metakaolin (MK) and limestone (LS) with their various physico-chemical, mineralogical, morphological and durability properties have been addressed along with life cycle assessment (LCA) studies. Based on the detailed literature survey, current challenges for conventional utilization of SCM based mortar have been identified along with future research gaps. It has been observed that GGBFS and SF are very effective in enhancing the fresh and hardened properties of low carbon cementitious paste and mortar. The ongoing research work on effective use of low-grade limestone slurry to develop low clinker factor binder, is also briefly discussed.
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The main objective of a stabilization/solidification (S/S) technology is to reduce the risks related to disposal and/or use of contaminated materials by minimizing the leaching of potential contaminants. Cement shows high strength, low permeability, and good durability, which make it a suitable material for the S/S of inorganic hazardous wastes. Recently, Low-Carbon Cements (LCC) have become highly interesting with the main advantage of lower environmental impact. The aim of the present chapter is to discuss the potential of LCC on waste S/S. The discussion will include blended Portland cement, alkali activated cement, magnesium-rich cement, and special cements (Calcium aluminate cement and calcium sulfoaluminate cement).
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Construction contributes substantially to climate change, given its intense use of natural resources, high energy demand, and raw material transport-/end product manufacture-related greenhouse gas emissions, which account for 33%–38% of the worldwide total. Against that backdrop, the sector has a vested interest in implementing strategies that attempt to valorize industrial by-products as secondary raw materials [recycled aggregates, RAs, and supplementary cementitious materials (SCMs)] as an avenue for transitioning to a circular economy model. This chapter reviews the international literature on the simultaneous use of aggregates recycled from C&DW and industrial waste as SCMs in the design of more eco-respectful recycled concretes. Further to the respective findings and depending on type and content, the inclusion of SCMs in recycled concretes has a variable effect on consistency, compressive strength, and carbonation penetration. In contrast, their use has proved to be beneficial in terms of water absorption, chloride penetration, and CO2 emissions. The conclusion drawn is that the manufacture of recycled concretes with SCM-bearing cement is a strategy that effectively enhances their mechanical strength while reducing the industry’s carbon footprint.
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The detrimental impact of Portland cement (PC) which is the primary binder in the production of cementitious materials such as concrete has called for a need to use alternative binders to produce concrete. Of such promising sustainable alternative to the conventional PC concrete (PCC) are alkali-activated concrete (AACs) which are produced by using a binder composed of an aluminosilicate precursor and alkali activator. In this study, blast furnace slag (BFS) was used as the primary precursors in the production of AACs. Amorphous raw rice husk ash (RRHA) was used at various dosages to partially replace BFS as the precursor. The corresponding influence of the RRHA content and curing conditions on the performance of AACs were evaluated. The two curing conditions utilized are ambient temperature curing and thermal curing for 24 hours at 60˚C followed by ambient temperature curing. Findings from this study showed that the use of RRHA as a 10% replacement of the BFS is optimum as it yielded enhanced mechanical and durability performance. It was also found out that the thermal curing of AACs for 24 hours before curing at ambient temperature is beneficial to improving the performance.
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To develop sustainable concrete, partial replacement of cement with silica fume, fly ash, GGBFS was attempted in addition to the replacement of river sand with granite sand at the proportions of 0%, 25%, 50%, 75%, and 100%. The investigation leads to the breakthrough of ideal Sulfate resisting concrete with optimal design mix consisting Granite sand 25% + river sand 75% + partial replacement of cement by 7.5% silica fume + 10% fly ash + 10% GGBFS. The analysis results with the Sulfate resistance through only a 12.2% reduction in the tested compressive strength for the optimum design. All other design mix considered for the study indicated with lesser Sulfate resistance varying from 13.2 to 17.1% of reduction in compressive strength. Conventional river sand with admixtures leads to decline in compressive strength from 40 to 33 N/mm2 however the optimum design mix as identified in the study resulted with the higher sulfate resistance. It is estimated that 2% total cost savings were achieved for the identified optimal design mix for the 1 m3 of conventional concrete. Total cost savings of 2% were achieved for the identified optimal design mix for the 1 m3 of conventional concrete based on the estimation. The goodness of fit using Chi-Square analysis has been carried out for the developed regression equation towards estimating the compressive strength for various design mixes resulted in a value of 0.82. Keywords River sandGranite sandXRDMagnesium sulfateConcreteTricalcium silicateDicalcium silicate
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The use of renewable energies and, more specifically, the existence of biomass-fired heat and power plants are being driven by European sustainability policies promoting nonfossil fuel-based power generation. The drawback is the generation of vast volumes of biomass ash (BA), both in the form of biomass bottom ash (BBA) and biomass fly ash (BFA). BA management and valorization is one of today’s priorities to mitigate bioenergy plants’ environmental impact, for most such waste is presently removed to landfills. This chapter addresses the scientific characterization of BA and assessment of its potential in new construction material design. Most research has focused on BA use in new cements as a supplementary cementitious material (SCM). The main obstacle to such potential use is the failure of the waste to comply with the chemical composition requirements set out in European standard EN 450-1 and US standard ASTM C618 (stricter in the former). More specifically, because most of the materials studied by researchers to date exhibit a low SiO2 + Al2O3 + Fe2O3 content and high proportions of total chlorides and alkalis, they are noncompliant with the aforementioned standards. Most do lie within the limit set for SO3, however. The few authors who have explored BA’s pozzolanicity with direct methods such as the Frattini or Chapelle tests have observed BA to be pozzolanic. Most BBA and BFA also exhibit satisfactory mechanical strength, with a strength activity index of ≥ 75% and a hydraulic index > 1. One of the conclusions drawn from this review is the identification of a need for an in-depth study of the durability of materials with BBA or BFA.
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