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Supplementary cementing materials

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... D.K Panesar showed in their work that on occasion, individual particles may unite to form small agglomerates, which can range in size from 1 to 100 m. (ACI-Committee-234, 2006). The specific gravity of silica fume ranges from 2.20 to 2.30[11]-[13]. ...
... 13 shows the immersion in water of the blocks for the curing process. ...
Thesis
Building construction and operations have a significant direct and indirect environmental impact. As we can see, the use of cement in concrete work has a negative environmental impact due to carbon emissions, and research has shown that every ton of cement produced emits half a ton of carbon dioxide, therefore there is an immediate need to limit cement use. As a result, we intended to reduce the negative environmental impact of the concrete work by replacing cement with supplementary cementitious materials such as fly ash, silica fume, and steel slag. The rationale for using steel slag as a partial replacement for coarse aggregate in concrete is due to its lightweight qualities, which may allow the structure to withstand higher applied loads. Using nanostructure and microstructure characterization tools and materials, the simultaneous and separate optimal use of cement-silica and nano-silica will result in a new concrete mixture that will result in long-lasting concrete structures in the future that can serve the more rigid and strengthening concrete structures. This thesis work has been done to analyze the change in compressive strength in concrete, reducing the use of cement and coarse aggregate, in the case of varying percentages of cement replacement circumstances. To get this job done, there’s been conducted a variety of laboratory tests change the partial cement replacement proportions with silica fume and fly ash and partial aggregate replacement with steel slag in the concrete mix. The test result showed that 15% silica fume, 10% fly ash, and 30% steel slag proportion withstand more load than the normal cement concrete mixture. The SEM test also supports the compressive strength test result by showing the internal bonding between the materials in the replaced binder-aggregate specimens. The XRD patterns of the materials used also enumerates the standardization and testing procedures. The usage of sustainable cementitious materials like fly ash, silica fume, and steel slag incorporates the motivation behind reducing the industrial byproducts/wastes generated in such an amount that hampers our mother nature. The overall representation of this research will emancipate the initiatives taken toward greener & sustainable construction.
... Silica fume (SF) is a by-product of smelting silicon and ferrosilicon in an electric arc furnace [27]. Smelting reduces high-purity quartz to silicon, producing SiO 2 vapors that oxidize and condense into micro non-crystalline silica particles. ...
... Influence of SCM replacement level on (a) compressive strength (b) carbonation depth of concrete[27]. ...
Article
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Alternative to traditional concrete, sustainable concrete reduces cement content, waste management issues, and CO2 emissions. To achieve sustainable concrete, waste materials can be used as supplementary cementitious materials (SCMs) to partially replace cement. Fly ash, ground-granulated blast furnace slag, and silica fume have been heavily studied as SCMs. However, due to the retirement of coal-fired power plants and switching to renewable energy, existing SCMs are losing their dominance. With SCMs becoming more widely accepted as partial cement substitutes, there is fear that the current supply will not meet future demand. As a result, researchers have been looking for alternative SCMs. The circular economy can be achieved by reusing non-hazardous construction and demolition materials, timber, and metal/steel production waste as SCMs. This article discusses emerging SCMs, reactivity evaluation methods, their limitations, and treatment methods that may improve reactivity. Emerging SCMs can replace existing SCMs in quantity, but their supply to cement factories and low reactivity due to stable crystallinity hinders their use. Among treatment methods, particle size reduction effectively enhances reactivity; however, very fine SCM may increase the overall water demand due to the large surface area. Decades-old reactivity evaluation methods have relatively weak correlations and thus misreport the reactivity of SCMs. Newer R3 models, such as calorimetry and bound water, give the best correlations (R ≥ 0.85) for 28-day relative strength and better performance. Additionally, more concrete testing with emerging SCMs under different durability and environmental protection conditions is required and life cycle assessments are needed to determine their regional environmental impact.
... After that, it swells 2.5 times on gaining sulphate exposure by converting into ettringite crystals resulting in cracking/ expansion [41,49]. The external attack of sulphate transforms monosulphate aluminate hydrate into long ettringite, needle-like crystals, creating cracking inside hardened concrete [50]. In contrast, the formation of micro-ettringite crystals in voids causes expansion in the structures [51]. ...
... In contrast, the formation of micro-ettringite crystals in voids causes expansion in the structures [51]. The magnesium sulphate attack produces gypsum and crumbly fibrous magnesium-silicate-hydrates gel, which does not have any strength and generates the final collapse of the structure [50][51]. ...
Article
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The exposure of engineering structures to complex chemical hazards in omnifarious geographical/ environmental locations and emission of greenhouse gases from manufacturing and usage of cement have encouraged researchers to explore the chemical synthesis taking place in the blending of different raw materials, formation of complex compounds, hydration of cement concrete and reactions taking place during internal/ external sulphate attacks. This study has carried out an in-depth elucidation of the contemporary research to understand better the raw material composition of cement-like calcareous and argillaceous minerals, the hydration process, the reaction of complex compounds to create cement paste, kinetics associated with the formation of ettringite, monosulphate aluminate ferrate hydrates, exchange of cations and anions between reactive metals hydroxide, hydrates, sulphates and their impacts on long term sustainability properties of concrete. An endeavour has been made to explore the use of lime and pozzolans derived from industrial, agricultural and natural resources. The microstructural studies were examined, which augmented the research findings that the development of cracks/ failure in concrete is attributed to the formation of ettringite, gypsum, brucite, M-S-H gel, thaumasite, portlandite, expansive silica hydroxide gel and carbonation of metal hydroxides due to internal/ external sulphate attacks on samples having more water-cement ratio and exposed to more concentrated magnesium/ sodium sulphate solutions.
... 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.
... 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.
... However, volumetric expansion might happen from unreacted CaO from GGBS reacting with sulphate ions to create gypsum and ettringite. Volumetric expansion in the GPC matrix could prevent crack formation and also prevent degradation of GPC [29]. The 28 days and 180 days durability performance of geopolymer concrete in terms of their resistance against sulphate attack was evaluated by immersing GPC specimen in 5% sodium sulphate solution (Na 2 SO 4 ) according to ASTM C 1012-04 [23]. ...
Article
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In the current experimental study, the durability studies such as rapid chloride permeability, sorptivity and early and long-term effect of sulphate attack were conducted on GGBS-SCBA based geopolymer concrete. Also elevated temperature behaviour of geopolymer concrete specimen subjected to temperatures of 200 ℃, 400 ℃, 600 ℃ and 800 ℃ were studied to evaluate the strength, mass loss and effect on microstructures due to elevated temperature. The degradation of geopolymer concrete at elevated temperatures was observed by scanning electron microscope, energy dispersive X-ray analysis, X-ray diffraction analysis and Fourier transform infrared spectroscopy analysis. From the test findings it is observed that the geopolymer concrete developed have good durability characteristics. It is also observed that geopolymer concrete retains more than 50% of strength up to a temperature of 600 ℃. From scanning electron microscope analysis of geopolymer concrete developed with GGBS and SCBA, it is found that there are larger crack formations and pores which are visible in the geopolymer concrete matrix when the specimens are exposed to an elevated temperature of 800 ℃ which confirms the degradation of C–A–S–H gel in the geopolymer concrete mixes developed.
... Because all BRAR values are greater than 1, it is clear that the CBP particles are neither spherical nor circular. It seems that such particles of CBP can likely control the water demand of cement-based composites as reported in literature (American Coal Ash Association, 2013;Panesar, 2019). Comparing the histograms in Fig. 6 illustrates that the milling conditions used in study did not contribute greatly to the significant differences in the computed BRAR values for the CBP specimens. ...
Article
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Starting from the observation that regular shape parameters such as equivalent diameter, area-perimeter ratio, circularity, compactness and roundness fail to adequately identify shapes of materials, alternative shape parameters are proposed to remedy this shortcoming. In this study, plugins in image analysis are extended to explore the major and minor elliptical axes and bounding rectangle dimensions in clay brick powder particles from changing milling conditions of different masses of clay bricks in ball mill. It turned out that with developed plugins in ImageJ, extracting such shape parameters of clay brick powder samples was not problematic. For the generated reciprocal aspect ratio (RAR) values ranging from 0.51 to 0.53, majority of the particles were noticed to be within the ellipse-inclined shapes. Using the feret major axis ratio (FMR) values for the formulated bounding rectangle dimensions, most particles appeared to be bound in rectangle-inclined shapes. Despite the generated major and minor elliptical axes and bounding rectangle parameters, grinding conditions in this research did not present any significant influence on such shape parameters of CBP specimens. It is believed that the developments of quantifying the major and minor elliptical axes and bounding rectangle dimensions of the CBP particles in this study are ground on solid foundations without need for extensive experimental works. The proposed developments are therefore valid and could be dedicated for characterising pozzolanic materials, because of their interests in cement-based composites.
... Sulfate attack is basically a deterioration mechanism which affects the properties of a cementitious mixture. Sulfate attack results in significant cracking, expansion, loss of connection between the cement paste and aggregate, and changes in paste composition, with the monosulfate phase converting to ettringite and eventually the development of Fig. 10 Effect of bleed water pH on initial setting time (Do et al. 2019) gypsum in the mix (Panesar 2019;Yuan et al. 2021). The severity of sulfate attack depends upon the moisture content and salt composition present in the cementitious mixture (Penttala 2009). ...
Article
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There is a recognized need to address the mismanagement of industrial by-products, as their accumulation severely threatens the environment. Efficient reutilizing of industrial waste is indispensable in realizing environment-friendly sustainable development. Towards this end, supervised adoption of controlled low-strength materials (CLSM) can be a solution. CLSM are cement-based materials which are environmentally safe, with self-levelling and self-consolidating properties. CLSM’s long-term sustainable applications exclusively depend on its geo-environmental properties during and after the construction phase. This comprehensive review explores the impact of geo-environmental properties on the plastic and in-service properties of industrial by-products used for CLSM creation. It critically examines various geo-environmental properties of CLSM comprising interlaced aspects of chemical composition, mineralogical composition, leaching behavior, pH value, and thermal conductivity. It is shown that the geo-environmental properties of CLSM are determined mainly by the characteristics and content of raw materials, wastes, and the quantity of water used in the final blend. Further, the review accentuates the geo-environmental properties’ detrimental effects on the plastic and in-service properties of CLSM. The comprehensive review can aid in effectively utilizing CLSM to reduce environmental concerns while achieving sustainable development.
... Sugarcane, sugarcane bagasse, and sugarcane bagasse ash are depicted in Fig. 3, which shows that SBA can have a colour ranging from black to ruddy grey [28]. Previous research has shown that the specific gravity values of RHA, POFA, and SBA are lower than that of OPC [29,32]. Specifically, the values of the specific gravity of RHA, POFA and SBA range from 1.94 to 2.3, 1.89 to 2.66, and 1.36 to 2.88, respectively [28,29,33,34]. ...
... The recommended rate for using slag as a replacement material in cement is 25-30% [14]. However, slag can be used instead of cement at 30-85% to conserve energy and natural resources and reduce CO 2 emissions and costs [15]. Its chemical compositions differ, depending the iron ore source and the smelting process [16][17][18]. ...
Article
In recent years, a great deal of importance has been attached to production based on the UN's sustainable development goals in the construction sector. Environmental solutions are sought for sustainable cities and communities during the concrete design and production stages. For this purpose, the properties of low-cement composites are frequently investigated. In this study, polypropylene (PP) fiber reinforced concrete with 10 or 20 kg/m 3 PP fibers and a cement content of 200 kg/m 3 was produced. In addition to cement, 800 kg/m 3 slag or fly ash (FA) was used in the blends. Fresh, physico-mechanical, durability, microstructure, environmental and financial properties of the blends were investigated comparatively. Addition of PP fiber reduced the fluidity of the blends. Oven-dry densities of the blends are lower than 2000 kg/m 3 91-day compression strength of slag-blended blends varies between 27.8 and 44.8 MPa, and the blends with FA addition vary between 23.4 and 30 MPa. While the 91-day splitting-tensile strength of the slag blends exceeded 3.0 MPa, the blends with FA remained below 2.0 MPa. Capillary water absorption values of the blends vary between 0.36 and 1.23 kg/m 2. Addition of PP fiber increased the resistance of the blends against deteriorations such as freeze-thaw, sulfate and wear. In SEM images, fiber stripping was observed in blends with FA. By using slag and FA, the carbon emissions and embodied energy of the blends were reduced 4 times than the reference blend. In addition, the cost of the blends varies between 15.2 and 153.5 USD/m 3. The addition of PP fiber had a negative effect on the sustainability and financial properties of the composites. As a result of minimization, it was determined that the combined use of slag and FA was more appropriate. It has been determined that the blends obtained can be used in structural applications and mass concretes.
... Some of these SCM are by-products of various industries and can have pozzolanic or cementitious properties, for example, fly ash (FA), silica fume (SF) and slag cement, among others. The use of SCM in concrete can benefit its workability, strength and durability properties and decrease its environmental impact [4]. ...
Article
Corrosion of the steel reinforcement is a serious problem that lessens the durability of concrete structures. Numerous research studies focus on the improvement of the concrete matrix and the protection of the reinforcing bars against corrosion. Fly ash and silica fume have been used for the former and inhibitors for the latter; nevertheless, corrosion is a very complex multifactorial phenomenon because the deterioration mechanisms involved in a simulated-marine environment differ from those involved in a natural environment. Despite these facts most corrosion studies have been carried out in a laboratory under accelerated conditions and using non-destructive testing. In this research, the effects of the water-cementitious materials ratio, fly ash, and a calcium nitrite-based corrosion inhibitor, as well as their interactions, were investigated as methods to prevent the corrosion of reinforcing steel in concrete containing silica fume. Specimens were exposed to a natural marine environment for seven years and the corrosive activity was monitored annually using electrochemical techniques. At the end of the exposure period, the specimens were visually inspected, autopsied and the chloride concentrations at the steel–concrete interfaces were estimated. The steel bars were extracted and their mass losses and pitting depths evaluated and finally tested for tension. The results show the underlying performance of fly ash, alone or in combination with CNI, improves the concrete matrix and is an effective corrosion prevention method.
... Fly ash is a well-known supplementary cementitious material that has been used for years in the technology of cementitious composites [108]. Figure 9c presents an analysis of how often researchers dealing with granite powder in their mixture compositions use fly ash. ...
Article
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This paper focuses on literature analyses of the impact of granite powder waste on the properties of cementitious mixes and composites. The influence of weather conditions on the properties of granite rocks is also analysed. The grains of granite powder waste are characterized. It was noticed that the results of the literature do not answer the question of whether granite powder has a positive or negative effect on cementitious mixes. Typically, granite powder allows for increasing the mechanical and functional properties of composites. The article also describes the literature gaps related to the topic and indicates future research perspectives on the functionalization of granite powder waste. The author discusses correlations and the impact of granite powder on the properties of cementitious composites and compares it with the literature. This paper compares the results of different authors using standard testing procedures but with the application of different modifications of compositions of cementitious mixes. The possibility of reducing the production costs and CO2 emissions of cement composites with the use of granite powder waste was indicated. An increase in packing density connected with using of granite powder as an admixture in cementitious systems is described. Recommendations related to the use of granite powder in cementitious composites are listed.
... These thin aggregates have better thermal and acoustic insulation qualities when used. Using coconut and oil palm shells as aggregate in concrete can enhance sustainability and reduce waste.The primary object of this study is to review the use of resource saving agro-industrial waste in LWC with respect to physical and mechanical properties [39][40][41][42][43][44][45][46][47]. ...
Article
The high demand for natural aggregates has created opportunities for the use of agro-industrial waste in the building sector brought on by rising urbanization and the disposal issue of agricultural and industrial waste. Numerous agricultural waste and industrial by-products are already employed in concrete in place of cement, fine aggregate, coarse aggregate and reinforcing elements. Furthermore, there is an increase in the use of Lightweight concrete (LWC) in civil structures such as high-rise buildings, off-shore structures, and long-span bridges owing to the need of concrete, lighter than the conventional one. Presence of natural aggregates makes the concrete dense and heavy, hence the use of lightweight aggregates (LWA), such as perlite, paper industry waste, expanded shale, volcanic pumice, slate, wood ash waste, and expanded polystyrene (EPS), in the production of LWC can effectively decrease the self-weight of a structure. In a comparable manner agricultural wastes, like oil palm shell (OPS), coconut shell (CS), rice husk ash (RHA) and industrial waste like fly ash, plastic aggregate, silica fume (SF), metakaolin (MK) have the potential of a LWA. This study reviewed the utilization of oil palm shells (OPS), coconut shells (CS), expanded polystyrene (EPS), and silica fume (SF) in concrete, among the numerous available agroindustrial wastes. For the past decade, research has been ongoing on aggregate processing to meet special concrete requirements such as low density, thermal insulation, and strength. These wastes exhibit similar properties to conventional concrete when used in combination with mineral additives like SF and RHA, among others. The study also highlights the eco-efficiency and functional benefits of using these wastes as lightweight aggregates (LWA).
... Sulfate attack is one of the deteriorations that could occur in concrete structure that is in contact with water that contains sulfate, such as seawater, groundwater, and swamp water [1]. Sulfate attack could occur due to the reaction between sulfate ions with calcium hydroxide and calcium aluminate hydrate to form gypsum and ettringite [2]. It was further explained that the formation of ettringite could lead to an increase in concrete expansion, and hence, cracking in concrete could be developed, while the formation of gypsum could lead to softening and loss of mass and strength of the concrete. ...
Article
Full-text available
Indonesia as a maritime country has a number of structures in coastal areas that are made from concrete. Sulfate attack is one of the common deteriorations that could occur due to the exposure of saltwater to the concrete. Unfortunately, the Type II and Type V cements, which are the special cements that are resistant to sulfate, are rarely used due to their high prices. The objectives of this research are to compare the performance of concrete mixture that was prepared by using the standard cement mixed with crystalline material and the concrete mixture that was prepared by using two different brands of Type V cement. There were five concrete mixture variations tested for their compressive strength and permeability. To assess the permeability of the concrete, the specimens were placed under pressured water for 72 hours and the water penetration depth was measured. From the research results, it was found that the usage of crystalline additive (CA) made the compressive strength increased at a faster rate and the concrete mixture that contained Type I cement and 0.7% of crystalline material had the highest compressive strength value. In terms of the permeability of the concrete, it can be seen that the specimens that were mixed with CA were more effective in stopping the water to penetrate the specimens than the specimens prepared with either of Type V cement.
... Thus, the gap between the cement particles is bridged by several numbers of fine SF powder. The SF powder can be mixed with cement at the time of mixing, and it can be blended with clinkers in the manufacturing of cement to get blended cement [13]. The concrete free with pores and dense structure is categorized as ultra-high strength concrete [14]. ...
Article
The present paper discussed the silica fume (SF) as the SCM to replace cement partially in concrete. The paper aims to summarize till date literature findings and suggest necessary gaps in utilizing SF as SCM. The study’s necessity and framework are highlighted through bibliographic analysis using VOS viewer software and Scopus search engine data and found a lack of research in the field of SCM in the last 5 years. The production process of SF and its physical and chemical properties are studied location-wise. The range of these properties is analysed, and it found that SF mean particle size is 10 times finer than cement which enhances the mechanical and durability of concrete. The mechanical properties studied reported that the optimum percentage of silica fume generally ranges between 7.5 and 12%. However, it is not constant and found to be dependent on w/c. An adverse effect on the characteristics of concrete was observed on excess addition of SF over the optimum limit. The feasibility of SF with other SCM and fibers was found effective in improving the concrete properties. The different properties based on the action of water transport through the concrete are studied, such as permeation, diffusion, migration, convection, void formation, sorption, wick action, absorption, and adsorption. The permeability properties were optimum between 7.5 and 10% SF. Further, the thermal performance of the building with and without SF-added concrete was performed using Revit software (BIM). It was reported that SF concrete is effective by 2.25 % and 4.30 % for cooling and heating load, respectively. Very few papers were found on the utilization of silica fume for the development of different construction products. The review concludes with recommendations for future research, aiming to stimulate more studies in this field.
... This silica fume is used to make additional silicon alloys, including calcium silicon, ferromagnesium, and ferromanganese (ACI 226-3R-87) [7]. The annual global consumption of silica fume surpasses 1 million tonnes [8][9][10]. The majority of steel slag is highly concentrated in Fe1-O and other metal oxides. ...
Article
Full-text available
Every ton of cement produced emits half a ton of carbon dioxide, so there is an immediate need to limit cement use. Cementitious materials such as fly ash, silica fume, and steel slag can be substituted for cement in making concrete more rigid and stronger. This research work has been done to analyze the change in compressive strength in concrete, reducing the use of cement and coarse aggregate, in the case of varying percentages of cement replacement circumstances. To get this job done, there's been conducted a variety of laboratory tests changing the partial cement replacement proportions with silica fume and fly ash and partial aggregate replacement with steel slag in the concrete mix. The test result showed that 15% silica fume, 10% fly ash, and 30% steel slag replacing proportion withstand more compressive load than the normal cement concrete mixture. The SEM test also supports the compressive strength test result by showing the internal bonding between the materials in the replaced binder-aggregate specimens. On the other hand, the flexural strength test came out with the best proportion of 15% cement replacement with fly ash and silica fume along with 10% coarse aggregate replacement with steel slag. The XRD patterns of the materials used also enumerate the standardization and testing procedures. The usage of sustainable cementitious materials like fly ash, silica fume, and steel slag incorporates the motivation behind reducing the industrial byproducts/wastes generated in such an amount that hampers our mother nature. The overall representation of this research will emancipate the initiatives taken toward greener and more sustainable construction.
... (2) CCR plays a positive role in the formation of CSH gels through hydration reaction, which can coexist with polymer gels. The simultaneous formation of CSH and polymer gels might be conducive to bridging the gaps between different gels and unreacted GGBS particles, thereby forming a denser and uniform matrix (Yip et al., 2005); (3) The addition of Ca 2+ can intensify polymerization process and shorten the polymerization time, thus improving reaction rate (Panesar, 2019). However, when CCR content exceeds the optimum, the UCS of stabilized samples decreases sharply. ...
... Silica fume (SiO2) and Steel fibers when used simultaneously can significantly increase the performance of concrete as silica fume is a cementitious material and it helps cement in establishing a strong bond with the steel fibers and reinforcements used in the member due to its fine particulate size between 0.1 to 0.3µm [2]. ...
Conference Paper
Concrete is one of the most commonly used construction material on the earth after water. The compressive strength of concrete is an important parameter and is considered in all structural designs. Production of the cement is directly proportional to carbon emissions. The cement content in the concrete can be partially replaced with waste materials like steel fibers, silica fumes, etc. Calculating compressive strength in a laboratory takes huge amount of time, manpower, cost and produces a large amount of wastage. Apart from the constituents of concrete , the compressive strength also depends on various factors such as temperature, mixing, types of aggregate, and quality of the water. The analytical models failed to deal with difficult problems. Artificial intelligence has enough capabilities to deal with such kind of complex problems. In this work, an artificial neural network (ANN) based model has been developed to predict the compressive strength of steel fiber and silica fumes-based concrete. The R-value of the developed model is 0.9948 and the mean absolute percentage error is 5.47%. The mean absolute error and root mean square error of the proposed model is 1.73 MPa and 6.89 MPa, respectively. The developed model is easy to use and reliable to estimate the compressive strength of concrete incorporating silica fumes and steel fibers.
... these lines, GGBS, which is essentially a byproduct of iron production companies, has been utilized as a partial or complete alternative for cement in the past [13,17,[30][31][32]. Incorporating these leftovers into concrete not only improves its mechanical and durability properties but also adds to its sustainability [33,34]. ...
Article
By understanding the importance of recycled aggregates in the development of sustainable environment, the present study investigated the corrosion performance of recycled aggregate concrete. Since the water to binder ratio has a substantial impact on the performance of concrete, corrosion studies was conducted on a wide spectrum of water to binder ratio varying from 0.25 to 0.75 at 0.1 intervals. In addition, the impact of 50 % ground granulated blast furnace slag on corrosion performance was investigated for the same range of water to binder ratio. For all these developed concretes, coarse natural aggregates were totally replaced with coarse recycled aggregates and their corrosion performance was explored through surface resistivity test, accelerated carbonation test, rapid chloride migration test, half-cell potential, and corrosion rate test. From the results it can be concluded that the inclusion of ground granulated blast furnace slag into the recycled aggregate concrete mix 1) achieved 70 MPa compressive strength in 90 days of curing 2) increased the surface resistivity to 88 kΩcm and 3) decreased the carbonation resistance. By accessing the real time corrosion resistance of steel inside the concrete, an increase in potential and decrease in corrosion rate was observed for ground granulated blast furnace slag based concrete. Hence, it can be concluded that the inclusion of ground granulated blast furnace slag in the recycled aggregate concrete mixes increased the corrosion resistance
... Historically it was considered as waste materials as it is produced in large quantities but due its high pozzolanic nature it is a very good supplement for the cement replacement. The compacted silica fume has a density of 200 to 600 kg/m 3 whereas its bulk density ranges between 130 to 630 kg/m 3 [12]. The intensity of SF is around 2.2-2.3. ...
Conference Paper
Concrete is the top most used compound material in construction usually made from a combination of cement, aggregates (fine and coarse) and water. The availability of concrete ingredients is limited and to overcome this issue, research is going on waste materials to be used as concrete ingredients and form a sustainable concrete. Using waste material in concrete may alter its properties in both ways, meaning it may form concrete more durable, more strengthened or may reduce its properties. In this literature, use of waste glass powder, rubber waste and silica fumes to form a sustainable concrete is discussed. A comparative analysis on the workability, strength, density, elastic modulus, water absorption is presented.
... In the last decade, there has been an increasing demand for applying various products such as silica fume, fly ash, and ground granulated blast-furnace slag to develop concrete and other cementitious products [7,8]. The addition of such an additive is typically preferred in cases to improve the presentation of cementitious material either in the initial state (such as by changing the rheology) or in the final state (for example, by improving mechanical and durability properties) [9]. ...
Article
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Sustainable materials present a significant revolution in the construction industry and exhibit tremendous potential to develop a green building material that can be adopted to lower the construction sector’s carbon footprint. This study details the development, mechanical and thermal properties of mortar produced using biochar derived from date palm leaves (BioCl) and date palm seeds (BioCs) as a cement additive. A detailed experimental protocol including flowability, compressive strength, the volume of permeable voids test, ultrasonic pulse velocity test, nondestructive crack identification, and thermal was conducted to understand the effect of adding biochar on the performance characteristics of mortar. The durability and mechanical test indicated that BioCl performed better than BioCs while both additive materials performed better than the control samples. Adding BioCl and BioCs to 0.75% and 1.00% improved the compressive strength to 7 and 5%, respectively, compared to the control samples. The ultrasonic pulse velocity direct and indirect method results were significantly reduced to a maximum of 22.54% and 20.46 with the addition of BioCl and BioCs in mortar. This further confirms the dense packing of biochar particles into the interfacial transition zone of the matrix. Biochar-masonry concrete blocks showed almost 41% lower thermal conductivity than control concrete, indicating biochar-based blocks’ high thermal performance.
... Among these mechanisms, permeation is the one that is usually associated with the durability performance of reinforced concrete [63], defining the ease with which a fluid flows through a porous material under a pressure gradient [63]. Permeability is influenced by the size, distribution and continuity of the pores [64], and it is accelerated by the presence of cracks which are considered to be a pathway to aggressive agents. Nevertheless, when harmful substances are present as salts or CO 2 , the diffusion mechanism plays the primary role in view of durability. ...
Article
Self-healing is recognized as a promising technique for increasing the durability of concrete structures by healing cracks, thereby reducing the need for maintenance activities over the service life and decreasing the environmental impact. Various self-healing technologies have been applied to a wide range of cementitious materials, and the performance has generally been assessed under ‘ideal’ laboratory conditions. Performance tests under ideal conditions, tailored to the self-healing mechanism, can demonstrate the self-healing potential. However, there is an urgent need to prove the robustness and reliability of self-healing under realistic simulated conditions and in real applications before entering the market. This review focuses on the influence of cracks on degradation phenomena in reinforced concrete structures, the efficiency of different healing agents in various realistic (aggressive) scenarios, test methods for evaluating self-healing efficiency, and provides a pathway for integrating self-healing performance into a life-cycle encompassing durability-based design.
... Therefore, by increasing GGBFS replacement rate, water absorption of the cementitious materials reduced, and the hydration process slowed down, and thus the setting time of the mixture increased. Other similar results showed that increasing the replacement amount of GGBFS increases the initial and final setting time (Malagavelli and Rao 2010;Hadjsadok et al. 2012;Panesar 2019). It is also clear from Fig. 15 Relationship between 3-piece and 4-piece mini-column segregation Content courtesy of Springer Nature, terms of use apply. ...
Article
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Reusing industrial by-products and agricultural waste as supplementary cementitious materials for producing sustainable concrete is one of the most promising ways to reduce cement production and the detrimental effects of concrete constructions on the environment. However, when it comes to preparing self-consolidating concrete (SCC) and mortar (SCMO) containing such materials in high volume, bleeding, and segregation of their fresh mixture are the crucial factors hindering their large-scale application. In this regard, the main aim of this study is to address such issues by designing sustainable SCMO using ground granulated blast furnace slag (GGBS) in high volume and rice husk ash (RHA) with comparatively lower environmental impact and high quality. To achieve this goal, the workability of fresh mixture and all its three main characteristics, including segregation resistance, passing ability, and filling ability, were evaluated with recently developed empirical apparatuses. For this purpose, 12 mixtures with different compositions were prepared to investigate the fresh properties, compressive strength, setting time, and environmental impact index. The results indicate that there are inextricable links between mixing proportions, strength, and carbon emissions of the mixture. Sustainable SCMO with an embodied-CO2 index lower than 4.5 kg/MPa.m3, good workability, and compressive strength of 49.7 MPa was designed by optimizing cementitious content, while the e-CO2 index of the control mixture was around 8 kg/MPa.m3. The addition of GGBFS and RHA not only decreased the e-CO2 index but also increased the unit cement strength contribution index. The results also indicated that by increasing GGBFS, the fluidity and segregation of the mixture increased while adding RHA increased viscosity and modified bleeding and the segregation index. Moreover, the growth rate of the compressive strength in mixtures containing GGBFS was much higher than that of the control mix at the same age. The promising results of this experimental study indicate that utilization of GGBFS and RHA in SCMO mixture can provide a practical way to reduce the environmental effects of cement production and pave the way for friendly disposal of slag and waste products.
... Ek olarak, donma-çözülme kaynaklı hasarların önlenmesi amacıyla polimer esaslı liflerde kullanılmıştır (Nam et al., 2016). Uygulanan yöntemler genellikle hava sürüklenmesi esasına dayanmaktadır (Dang et al., 2014;Jones and Weiss, 2014;Panesar, 2019 ...
Conference Paper
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Forecasting techniques are evaluated with past data before forecasting future figures. Error series of past periods are used to calculate error statistics to evaluate accuracy of forecasting technique or to compare different methods. Forecast accuracy measures of MSE, RMSE, MPE, MAPE, SMAPE and Theill’s U will be evaluated with Turkish gasoline cars sales data set. ARIMA, ANN and exponential smoothing forecasting techniques will be used to generate forecasts of past periods. These forecasts are evaluated with the given forecast accuracy measures. Selected forecast accuracy measures presented consistent results about selected forecasts.
... 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.
... 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.
... 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
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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.
Chapter
Cement bricks are generating huge carbon emissions during their manufacturing process, and due to the high carbon emissions, global warming takes place. To avoid those circumstances, new inventions are needed in bricks, and at the same time, the new material which is used for replacement should emit low carbon emissions. A sustainable industrial by-product ground granulated blast furnace slag (GGBS or GGBFS) was introduced here. The slag was partially replaced with cement on 25 and 30% as a binder material which gives compressive strength from 7 to 24 MPa on its 28-day strength. The water absorption of the bricks is found to be 4–7% which is normal when compared to the nominal brick water absorption range. The raw materials used for this brick were GGBS, Ordinary Portland Cement, and M-Sand. Most of the high-strength bricks were developed by adding iron ore tailings, GGBS, etc. in bricks, but here GGBS itself gives high strength in terms of brick standards. To develop a sustainable construction material, slug is used here in a potential way. It is also found that the size of the slag is comparatively less than Ordinary Portland Cement and the compressive strength gets increased rapidly as the slag particles settle in between the gap present in cement molecules. Finally, as the cement is partially replaced by 30%, the carbon emission is also comparatively reduced.
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Industrial solid waste has a wide range of impacts, and it is directly or indirectly related to land, atmosphere, water, and other resources. Industrial solid waste has a large amount of production, complex and diverse components and contains a variety of harmful substances. However, as industrial by-products, it also has a lot of available value. Industrial solid waste has been continuously studied in water treatment due to its special composition and porous and loose structure. It is known that there are few reviews of various industrial solid wastes in the field of wastewater treatment, and most of them only discuss single industrial solid waste. This paper aims to sort out the different studies on various solid wastes such as fly ash, red mud, wastewater sludge, blast furnace slag and steel slag in dyeing, heavy metal, and phosphorus-containing wastewater. Based on the modification of industrial solid waste and the preparation of composite materials, adsorbents, coagulants, catalysts, filtration membranes, geological polymers, and other materials with high adsorption properties for pollutants in wastewater were formed; the prospect and development of these materials in the field of wastewater were discussed, which provides some ideas for the mutual balance of environment and society. Meanwhile, some limitations of solid waste applications for wastewater treatment have been put forward, such as a lack of further researches about environment-friendly modification methods, application costs, the heavy metal leaching, and toxicity assessment of industrial solid waste.
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The unique physical and chemical properties of silica fume enhance the compressive strength and water resistance of cement mortar. The study aims to investigate the effect of silica fume in cement mixes in terms of strength-gaining characteristics and water-resistance attributes. The silica fume was added in amounts of 0%, 10%, 20%, and 25% as a partial cement replacement for the production of mortar. A total of 120 mortar cubes were prepared with steel molds of 50 × 50 × 50 mm dimensions. Two water-cement ratios (w/c) of 0.4 and 0.5 were utilized to investigate the water-resistance properties. A water-resistant property was calculated using the compressive strength ratio in the saturated surface dry (SSD) state to the oven-dry condition. The compressive strength ratios in SSD and the oven-dry state were measured after curing in water for 3, 7, 28, 45, and 90 days. After 90 days of curing, the sample with a water-cement ratio of 0.4 exhibited the greatest compressive strength and the highest ratio of SSD to the oven-dry state. The higher SSD to oven-dry strength ratio shows the silica fume possesses superior water resistance. This study concludes that silica fume possesses great pozzolanic activity and excellent resistance to water. The incorporation of silica fume creates a concrete composition that enables the construction of durable concrete structures.
Article
Coal bottom ash (CBA) is claimed to carry some pozzolanic qualities that can be stimulated by pre-treatment. This study investigates the feasibility of partially replacing ordinary Portland cement (OPC) with ground CBA to produce CBA-cement paste. A thorough experimental program was designed to explore the effect of the CBA source and particle size, liquid-to-binder ratio (l/b), and superplasticizer (SP) on the 28-day compressive strength of CBA-cement paste. The CBA source with a high SiO2/Al2O3 ratio (approximately 3.6) and CaO content (5.3%) yielded higher compressive strengths. Grinding breaks down the large raw CBA particles and enhances their reactivity with water and pozzolanic character. Specimens with 50% ground CBA attained a 28-day compressive strength of up to 51 MPa at l/b of 0.225. The low pozzolanic nature combined with the porous texture of CBA necessitates the incorporation of a superplasticizer to enhance workability at low l/b. A 28-day strength of 61 MPa was achieved at 30% cement replacement with 150 μm CBA at l/b of 0.25 using 1% SP. In view of this, partial replacement of cement with ground CBA has proven to be a viable and sustainable construction option.
Chapter
Concrete is one of the most commonly used construction material on the earth after water. The compressive strength of concrete is an important parameter and is considered in all structural designs. Production of the cement is directly proportional to carbon emissions. The cement content in the concrete can be partially replaced with waste materials like steel fibers, silica fumes, etc. Calculating compressive strength in a laboratory takes huge amount of time, manpower, cost and produces a large amount of wastage. Apart from the constituents of concrete, the compressive strength also depends on various factors such as temperature, mixing, types of aggregate, and quality of the water. The analytical models failed to deal with difficult problems. Artificial intelligence has enough capabilities to deal with such kind of complex problems. In this work, an artificial neural network (ANN) based model has been developed to predict the compressive strength of steel fiber and silica fumes-based concrete. The R-value of the developed model is 0.9948 and the mean absolute percentage error is 5.47%. The mean absolute error and root mean square error of the proposed model is 1.73 MPa and 6.89 MPa, respectively. The developed model is easy to use and reliable to estimate the compressive strength of concrete incorporating silica fumes and steel fibers.KeywordsCompressive StrengthANNSilica fumeSteel fiber
Chapter
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The aim and scope of the present study were to determine the efficacy of UFFA in evaluating the workability, static and dynamic stabilization properties, retention period, and slump loss of SCC systems in their fresh state, as well as their compressive strength at various ages. Microstructure (SEM and XRD) of blended SCC systems were studied. Also, the thermogravimetry behavior of blended SCC specimens were researched. According to the evaluated results, incorporating up to 20% UFFA into fresh concrete improved its performance due to its engineered fine particle size and spherical geometry, both of which contribute to the enhancement of characteristics. Blends of 25% and 30% of UFFA show effect on the water-binder ratio and chemical enhancer dosage, resulting in a loss of homogeneity in fresh SCC systems. The reduced particle size, increased amorphous content, and increased surface area all contribute to the pozzolanic reactivity of the early and later ages, resulting in denser packing and thus an increase in compressive strength. The experimental results indicate that UFFA enhances the properties of SCC in both its fresh and hardened states, which can be attributed to the particles’ fineness and their relative effect on SCC.
Article
Although geopolymer cement (GPC) is a substitute for Portland cement, its application is restricted due to the need for high-temperature curing (40–90 °C), which makes it challenging to utilise for onsite applications. To address this issue, the current study examined the potential of substituting fly ash (FA) with teff straw ash (TSA) in geopolymer mortars cured at ambient temperature. The findings revealed that substituting FA with TSA can eliminate the need for high-temperature curing, and the compressive strengths of FA-TSA-based geopolymer mortar mixtures cured for 28 days ranged from 45 to 53 MPa. Further, increasing the TSA content enhanced the mortar's flexural and direct tensile strengths. A teff straw ash level of 10% increased compressive, flexural, and direct tensile strengths by 40%, 59%, and 30% at 28 days, respectively. Furthermore, the mineralogical phases of the mortar after 28 days confirmed the presence of gismondine coexisting with other phases, and microstructural analysis indicates that the inclusion of TSA resulted in a denser structure. These findings suggest that TSA could be a potential substitute for FA in GPC applications to lower energy usage and environmental impact.
Chapter
Quantum computing (QC) is founded on the principles of quantum entanglement and the superposition of matter. It employs advanced computation techniques rather than conventional ones. To circumvent the limitations of conventional computing, new supercomputers employ quantum mechanics knowledge, which allows for the coherence of ones and zeros. Several fields like finance, healthcare, cybersecurity, transportation, climate change, and many more are taking advantage of QC. Indoor environmental quality (IEQ) is also one of the sectors that can benefit enormously with QC. The IEQ contains several parameters. Major IEQ parameters are indoor air quality, thermal comfort, acoustic comfort, and visual comfort. These parameters are associated with several physical, chemical, and biological components, which need critical computational considerations for accurate results and better understanding as the data can be highly overlapped. This chapter contains possible forthcoming research opportunities available in the collaborative work between “indoor environment” and “quantum computing.”
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A brief review of the evolution and origins of Ultra-High Performance Concrete (UHPC) is covered in this article. UHPC is a unique concrete with unique features such as workability, mechanical properties, and durability that differs from regular concrete and high-performance concrete in terms of mix composition, needs, and manufacturing methods. In terms of the material ingredients of UHPC, Silica Fume (SF) plays a critical role in the production of UHPC due to its unique physical and chemical properties. Ground Granulated Blast Furnace Slag (GGBS), a highly reactive pozzolan similar to SF, is another viable contender among mineral admixtures. As a result, this article examines the effects of SF and GGBS in the UHPC combination. This paper also reviews the durability of UHPC in terms of water and chloride-ion permeability. A brief review of the importance of steel and polypropylene fibre (PPF) in UHPC blends, as well as their pull-out behaviour, is also reviewed.
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Concrete exposed to splash zone in partially submerged concrete structures deteriorates rapidly due to reasons such as wetting-drying cycles, the impact of waterborne materials, bio-deterioration, chloride and sulphate attacks. Existing condition assessment and rating systems do not adhere to the interrelation between different performance attributes of splash zones and these models are extremely subjective to the performance of the evaluator. The objectives of this study are to evaluate the effectiveness of parameters that deteriorate marine concrete structures and to develop a new model to predict the rate of deterioration of splash zone in marine concrete structures. The fuzzy Analytical Hierarchy Process (FAHP) was used to develop the model to predict the rate of deterioration. Here, local factors were grouped under five primary parameters as visual inspection, water quality, casual factors, Non-Destructive Tests (NDTs) and crack details. Data relevant to 15 structures were gathered by visual inspection, laboratory and field experiments to validate the proposed model. Attributes of water quality achieved the highest priority for the deterioration of the slash zone of marine concrete structures. Further, numerical values were assigned to this rating model to avoid ambiguity and vagueness of linguistic descriptors in existing rating systems. Finally, the model developed in this study can be used to evaluate the deterioration percentage of the splash zone in structures and according to that appropriate retrofitting and repair work can be done.
Chapter
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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