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Supplementary cementing materials
... Meanwhile, the quartz heating in fume route is carried out under plasma electric arc furnaces under extreme temperatures, surpassing 3000 °C at the arc zone. The high temperatures cause the material to vaporize and the resulting fumes are collected and condensed to obtain silica [17][18][19]. Besides the huge energy supplied, high process temperatures lead to enormous NO x formation [20,21]. ...
... Quartz is then reacted with Cl 2 gas and carbon in the form of char at 1100 °C to produce SiCl 4 through reaction 4. This is followed by a reaction at up to 2000 °C in plasma electric arc furnaces (the temperature at the arc zone can exceed 3000 °C) until silica vapor is formed, reaction 5 [17][18][19]41]. This extreme temperature is generated by applying high voltage of electricity of about 1400 kV [12]. ...
... This extreme temperature is generated by applying high voltage of electricity of about 1400 kV [12]. The silica vapor is then condensed to produce small spherical silica particles [17][18][19]42] with the phase of crystalline. The composition of this product reaches 96-98% SiO 2 , 0.1-1.5% Al 2 O 3 , 0.5-0.6% ...
Rice husk valorization to produce silica is believed to involve an eco-friendly process rather than silica production from conventional and fume routes. Nevertheless, the quantitative point of view regarding this is still not widely disclosed. In this study, a simple material and energy input–output analysis (M&E I/O) is employed to compare the environmental impact of the production of 1 tonne of silica from conventional, fume, and biomass thermochemical conversion routes. The scope consideration includes raw material, transportation, utility systems, main production process, and output streams as environmental impact. Results show that conventional and fume routes need 3.86 tonnes of sandstone and biomass thermochemical conversion route needs 6.56 tonnes of rice husk. For conventional and fume routes, energy is supplied from 1194.08 and 1954.99 kg of coal combustion, whereas the biomass thermochemical conversion route uses rice husk as fuel and additional coal of only 238.38 kg. Further, the lowest CO2-equivalent emission of 0.85 tonnes is nominated to the biomass thermochemical conversion route, while conventional and fume routes are 10.09 and 18.62 tonnes, respectively. The produced wastewater from conventional, fume, and biomass thermochemical conversion routes is 27.27, 27.13, and 24.76 tonnes, successively. This study concludes and proves that silica production from rice husk is more eco-friendly and has low environmental impact, but wastewater treatment to meet the effluent standard should be applied.
Graphical Abstract
... Alyamac et al. [85] 2016 Marble powder Proposed method based on RSM and ANOVA. Esmeilkhanian et al. [86] particles. The coarse aggregate volume ratio should be fixed at 0.5, and fine aggregate content should be assessed using a V-funnel test using standardized coarse aggregate (glass beads). ...
... Sulfate attack occurs when sulfates react with compounds in cement such as monosulfate, portlandite, and CeSeH gel. This can lead to extensive cracking, expansion, and loss of bond between cement paste and aggregate [86]. ...
... FA is generated in coal-fired plants. Pulverised coal ignites in the boiler, producing heat and molten residue that cools to form ash [97]. Bottom ash settles in the combustion chamber, while fly ash remains suspended and is removed by electrostatic precipitators or baghouses. ...
This study evaluates the environmental impact of alkali-activated concrete materials (AACMs) as alternatives to conventional concrete. The influence of binder and activator content and type, along with other mix parameters, is analysed using a probabilistic embodied carbon assessment on a large dataset that includes 580 mixes. Using a cradle-to-gate approach with region-specific life-cycle inventory data, emissions are analysed against binder intensity, activator-to-binder and water-to-binder ratios, and fresh/mechanical properties. A multicriteria assessment quantifies the best-performing mix in terms of embodied carbon, compressive strength, and slump. AACM environmental impact is compared to conventional concrete through existing classification schemes and literature. AACM emissions vary between 41 and 261 kgCO2eq/m3, with activators contributing the most (3–198 kgCO2eq/m3). Uncertainty in transport-related emissions could shift these values by ±38%. AACMs can achieve up to four-fold less emissions for high-strength materials compared to conventional concrete, although this benefit decreases with lower mechanical properties. AACM environmental sustainability depends on activator characteristics, curing, mix design, and transportation.
... O efeito de nucleação proporciona uma cinética de reação mais veloz das partículas de cimento, aumentando a quantidade de produtos hidratados em um menor intervalo de tempo, influenciando diretamente na resistência mecânica. Enquanto isso, o efeito filler é a capacidade que as partículas finas têm de preencher os vazios da matriz, tornando o material mais coeso e dificultando a ruptura (Panesar, 2019). ...
RESUMO O objetivo deste artigo é avaliar o efeito do uso do resíduo de cerâmica vermelha (RCV) como material cimentício suplementar na resistência à compressão e na durabilidade do concreto. O RCV foi beneficiado e caracterizado físico-quÍmica e microestruturalmente. A atividade pozolânica foi avaliada pelo método Chapelle modificado e pelo método da resistência à compressão relativa. A substituição de cimento Portland (CP) por RCV no concreto foi realizada nos teores de 5%, 10% e 15%. Foram realizados ensaios de resistência à compressão aos 1, 7, 14, 28, 56 e 91 dias. Aos 28 dias, foram medidos parâmetros de durabilidade (absorção de água, índice de vazios e penetração de água sob pressão). O RCV apresentou atividade pozolânica com índice de desempenho de 91,7% e índice Chapelle de 557 mg de Ca(OH)₂. O teor de substituição de 10% de RCV apresentou o melhor resultado na resistência à compressão (45,1 MPa aos 91 dias), superando o concreto de referência. Teores de 10% e 15% de RCV estiveram associados a aumentos na absorção de água, índice de vazios e penetração de água sob pressão. Palavras-chave: Resíduo de Cerâmica Vermelha, Material cimentício suplementar, Atividade Pozolânica, Desempenho Mecânico, Durabilidade.
... This section terminates with visual inspection of cubes, cylinders and beams. Overall, the study evaluates the need for potential sustainable non-conventional concrete ingredients mentioned in literature (Alwesabi et al., 2020;Endale et al., 2023;Gjorv and Sakai, 2000;Panesar, 2019). ...
Under the effects of waste materials, non-conventional concrete mixes usually exhibit reduced costs, because of the use of waste materials compared with conventional concrete materials. On the other hand, the criteria for reducing the concrete cost should simultaneously incorporate the concrete performance. However, balancing the cost and performance of concrete incorporating waste tyre rubber (WTR) and clay brick powder (CBP) is still unclear. This study establishes a simple yet representative correlation between concrete cost and performance to illustrate the applications of modified concrete mixes containing CBP and WTR for sustainable construction. The study uses experimental works of compressive, split tensile and flexural strengths to assess the performance of concrete containing CBP and WTR. This information is exploited to determine concrete mixes capable of reducing cost at considerable concrete performance. The results highlight that the contributions of CBP and WTR to reductions of concrete cost cannot be neglected, particularly when high contents of these waste materials are used. Considerable relationships between costs and mechanical properties are validated using several examples, including the coefficients of determination of more than 0.65. While the inclusion of WTR addresses the issue of cost reduction in concrete, it falls short in improving the performance of concrete. It is demonstrated that the 5P0T concrete mix (5% CBP and 0% WTR) offers reasonable concrete performance and plausible cost reduction for use in sustainable construction. Moreover, the results provide theoretical and technical support on the contents of CBP and WTR that can achieve cost-performance balance. Therefore, the correlations between the cost and performance of the concrete presented here can be crucial in generating new non-conventional concrete mixes for sustainable construction.
... If mortar mix contains reactive silica, high alkalis can trigger a detrimental alkalisilica reaction. alkali-silica reaction creates a gel that expands within pervious concrete, causing cracks and significant strength loss (Panesar 2019). There is a threshold level for equivalent alkalies content. ...
... For instance, one of the most effective strategies to lessen this environmental impact involves replacing clinker with supplementary cementitious materials (SCMs) [7]. The addition of SCMs to blended cements triggers various reactions, influenced by their physical (especially specific surface area) and chemical/mineralogical composition [8]. SCMs in the form of chemical admixtures has emerged as a widely accepted solution for improving the performance of low-clinker cements and concrete [5,9,10]. ...
Faced with challenges like resource depletion and climate change, the cement industry needs sustainable solutions. This study explores the potential of geologically-delinaeated black shale from Apersua, Ghana, as a supplementary cementitious material (SCM) to reduce reliance on traditional methods. The researchers analysed the shale's chemical composition and mineralogy, then created laboratory cement formulations with varying black shale content. These were compared to standard formulations without shale. The results show cement with black shale has comparable compressive strength, meeting standard requirements. Even a formulation with only black shale (excluding limestone, a common ingredient) passed strength tests. Overall, the black shale demonstrated good potential as a SCM based on strength, chemical makeup, setting time, and its possible contribution to durability. This research suggests that black shales from Apersua are worth exploring further as a sustainable and potentially cost-effective alternative in cement production.
... The problem behind the use of high-volume fly ash in concrete mixes is the delay in setting and the slower rate of strength gain at the beginning of age [5]. Slag can be substituted for up to 70% clinker; however, its availability is inadequate [6]. Therefore, it is necessary to identify new sources of inorganic materials as partial cement replacements to protect the environment and sustainability. ...
Low-grade limestone (LGL) is not used to produce cement clinker, but this leftover material in cement quarries increases the water demand when used as a filler in concrete production. In this study, the effect of six commercial superplasticizers on the performance of cement mixes containing 35% LGL and 2% gypsum was investigated. The optimal doses of these superplasticizers were found in a range of different water/binder (w/b) ratios by conducting several Marsh cone and mini-slump tests. The addition of a superplasticizer with a higher active solid content produced a maximum cement flow, regardless of the w/b ratios. The LGL-based mortar samples admixed with this superplasticizer obtained a maximum compressive strength of about 36 MPa at the end of 28 days. SEM and XRD results showed the formation of a new calcium-rich mineral in their microstructure. These findings highlight the impact of the type and properties of superplasticizers on the performance of concrete mixes containing LGL as a supplementary cementitious material.
... A higher level of GGBS substitution may increase the cement content and quickly achieve an equivalent 28 d strength [26]. According to reports, for OPC concrete mixtures, GGBS replacement rates of 50 and 65 % increased the concrete strength by 8.6 and 19.5 %, respectively [27][28][29]. In addition, an extensive investigation was conducted for 90d on OPC concrete mixed with FA and GGBS. ...
This paper aims to examine the effect of coal gangue aggregate (CGA), fly ash (FA), and ground-granulated blast slag (GGBS) on the rheological, mechanical and microstructure properties of concrete. The rheological properties , compressive strength, splitting tensile strength, flexural strength, and uniaxial tensile behaviour of coal gangue concrete (CGC) were determined, and the microstructure of the concrete mixtures were investigated by use of XRD and SEM analyses. The results revealed the action mechanism of CGA and mineral admixtures on the microstructure and macroscopic properties of CGC. FA first increased and then decreased the yield stress and plastic viscosity, while GGBS considerably increased the yield stress and plastic viscosity. Furthermore, a constitutive model was established for CGC containing FA and GGBS under compression. The proposed stress-strain model for CGC is accurate and can be used for nonlinear analysis of structures made of this type of concrete. Moreover, the addition of FA and GGBS consumes calcium hydroxide, but increases products such as hydrated calcium silicate aluminate. These findings elucidate the understanding and optimisation of CGA use in concrete production, while contributing to lowering carbon emissions.
... Cement production requires significant raw materials and energy, which harms the environment. For a future building that is environmentally friendly, an alternative to OPC concrete is geopolymer concrete (GPC) (Gill et al. 2023a, b;Robayo-Salazar et al. 2018), which has a substantially lower environmental impact than Portland cement concrete (Gill et al. 2023a, b;Panesar 2019). In 1978, Davidovits initially presented Geopolymers as a novel family of inorganic polymer binders (Abdel-Gawwad and Abo-El-Enein 2019; Ekinci et al. 2019;Kanagaraj et al. 2023;Moradikhou et al. 2023). ...
The amount of cement used has increased phenomenally due to the development and massive expansion of the infrastructure sector. The manufacture of cement requires more incredible embodied energy and produces greenhouse gases. Geopolymer concrete (GPC) was developed to alleviate the environmental adverse effects caused by carbon dioxide emissions (CO2) and the extensive use of fossil fuels in cement manufacturing. GPC concrete is more durable and has better mechanical properties than traditional concrete; for all types of concrete composites, including GPC, compressive strength (Cst) is the most essential engineering property. The result is impacted by a multitude of factors, encompassing the number of binder materials utilized, the proportion of alkaline activators to binder (AL/Bi), the quantity of additional water incorporated, the dosage of superplasticizers, the ratio of alkaline activators (AAR), the concentration molarity of hydroxide of sodium (SHy), the temperature of curing, and the duration of cure. This review article aims to illustrate how these various parameters affect the compressive strength of fly ash-based geopolymer concrete (FAGPC). To accomplish this, an extensive dataset was gathered and analyzed. The results indicate that the compressive strength of FAGPC is mainly influenced by the temperature for curing, the amount of sodium hydroxide, and the amount of alkaline in the binder.
... The WTE was equipped with air, solid, and water pollution control systems to keep the surrounding environment safe. One technology often used to process flue gas combines quenching 22,23) , chemical adsorption using slacked lime and activated carbon, and bag filtering 24) . Quenching and chemical adsorption function to reduce the level of acid substances, whereas the bag filter functions to filter out particulates carried by flue gases before being discharged into the environment through the chimney 25) . ...
The incineration of municipal solid waste (MSW) effectively reduces waste and has a side product, such as electricity. The waste-to-energy (WTE) power plant in Bantargebang is the first national pilot plant facility in Indonesia using moving grate incinerator (MGI) technology, with a 100 tons/day design capacity and a maximum design of electricity power output of 750 kW. The main challenge of WTE in Indonesia is high moisture content (MC) and unsorted waste. Hence, it is imperative to include the pre-treatment facility through waste drying and sorting. In this work, over 241 working days from January to December 2022, approximately 15,451.35 tons of MSW (averaging 70.55 tons/day) have been incinerated at an average temperature of 613.8 o C. Waste pre-treatment alleviates waste MC from 20.13% to 8.59%. This process achieves a significant waste mass reduction of 81.52-96.50%. In addition, the system generates superheated steam at maximum values of 5000 kg/h, 340 o C, and 38-39 barA. The total electrical energy generated (956.04 MWh) is used to supply the electrical energy demand of the internal plant operation (1368.78 MWh). Moreover, the wastewater and flue gas in this WTE have successfully been processed by the pollution control systems to meet national standards. The fly and bottom ash from MSW incineration have proven harmless and suitable for construction material or cement admixture. This work conclusively shows that WTE Bantargebang provides positive implementation in almost all aspects, encompasses a significant amount of waste reduction, satisfying incineration performance, a significant amount of electricity generated, and the environmental performance does not harm the surroundings. Related to the performance deficiencies found is expected can be a valuable input for WTE development in Indonesia.
... 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]. ...
Peat is spread across the Sarawak state of Malaysia, covering about 69.08% of the land. It’s worth mentioning that peat is becoming a massive challenge for the construction industry. Thus, stabilization of peat using waste pozzolans to improve its strength is needed. In this research, silica waste combined with the Ordinary Portland Cement (OPC) is used as a stabilizing agent. This research aimed to investigate the effect of silica fume (SF) derived from a metal alloy industry to replace OPC in peat stabilization. The physical properties of peat were investigated to assess and characterize the parent peat. Subsequently, the effect of SF and OPC was determined using mechanical testing. Due to the application of hydraulic binders, the treated samples were cured for 7 and 14 days to assess the strength enhancement using SF and OPC. Finally, scanning electron microscopy (SEM) with energy dispersive x-ray analysis (EDX) was used to investigate the microstructural variation of the untreated peat along with the depth. Based on the results, it is concluded that the derived peat was hemic and sapric in nature with high water and organic contents. Also, the unconfined compressive strength (UCS) results revealed that the untreated peat possesses a meager strength of about 10.29 kPa. The UCS value was enhanced to 744.06kPa with the incorporation of 50% of SF. It is also found that the peat strength increases with the increasing curing period. Thus, an industrial waste (silica fume) can be used as a replacement for OPC to stabilize peat and increase its strength. Lastly, the morphological results revealed that peat becomes more humified and compact with increasing depth. Also, the energy dispersive x-ray analysis shows that the composition of peat varied less with the depth and possessed almost the exact percentages of the elements.
... One of the promising materials used as cement replacement material (CRM) is silica fume. Incorporating silica fume, an extremely pozzolanic byproduct of the ferrosilicon industry, can strengthen and increase the durability of concrete [5,6]. The study conducted by Shijun Zhao et al. [7] has recommended that producing high-performance concrete with excellent mechanical qualities may be accomplished by using SF as a replacement for modest volumes of cement in the mix. ...
... Soluble sulfates in recycled sand are 0.51%, which is below the 1.3% maximum authorized limit in French standards for the reuse of recycled aggregates in road applications [25]. The presence of sulfates and chlorides in recycled sand leads to ettringite formation and a decrease in strength, and limits the perspective of reuse of this aggregate for structural applications due to the swelling of sulfate in rich soils [36,37]. ...
The production of construction and demolition waste (CDW) in urban areas is growing rapidly. While the storage and disposal of CDW waste is costly, its recovery can help to conserve natural resources. This study investigates the characteristics of recycled sand obtained from the processing of CDW waste and the possibility of its reuse for pedestrian pathways. Physico-chemical and mineralogical characteristics of the recycled sand were investigated for its reuse. The percentage of fine particles in sand (below 0.63 μm) is 2.8%. The grain size of sand fulfills the particle size requirement of French standards. The methylene blue value of sand is 0.05 g/100 g. The GTR classification of recycled sand is D2 which is insensitive to water and suitable for road applications. A mineralogical analysis of soil shows that quartz, albite and microcline are important minerals in recycled sand. XRF analysis shows that CaO and SiO2 are major oxides in the recycled sand. The characterization of sand was followed by a manufacturing of cylindrical specimens of sand to observe the compressive strength. Samples were compacted with dynamic compaction by applying the Proctor normal energy of 600 kN·m/m3. The compressive strength testing of specimens shows that non-stabilized sand samples have compressive strength around 0.1 MPa which is considerably lower for its reuse in pedestrian pathways and road applications. Due to the low bearing capacity of sand, recycled sand was stabilized with the addition of binders such as Rolac (hydraulic binder), ground-granulated blast furnace slag (GGBS) and ECOSOIL® (slag mixes) with different percentages of the binder ranging from 0 to 7% for the optimization of the binder and for economic efficiency. The compressive strength of sand samples increases with the increasing percentage of the binder. The increase in strength is more important with a higher percentage of binders (5%, 6% and 7%). At a 7% binder addition, specimens with Rolac, GGBS and ECOSOIL binders show the compressive strength of 1.2 MPa, 0.5 MPa and 0.5 MPa. At a 7% Rolac addition, specimens have a compressive strength higher than 1 MPa and meet the strength requirement for soil reuse in the foundation and subbase layers of roads with low traffic. The experimental work shows that recycled sand can replace conventional quarry sand for road applications and pathways with the addition of a local binder, which is an eco-friendly and economical practice.
... µm, approximately 1/100 of the cement particle size. The specific surface area of silica fume falls within 13,000-30,000 m 2 /kg [32]. In the case of fly ash, the mean particle size is within 0.4-100 µm, around 1/30 of cement particles [33]. ...
... Common SCMs include fly ash, slag, and silica fume. These materials, obtained as by-products from industrial processes, possess pozzolanic properties and can enhance concrete strength, durability, and workability while reducing CO 2 emissions (Juenger et al., 2019;Panesar, 2019). Amongst various approaches to achieve low carbon concrete, utilizing Supplementary Cementitious Materials (SCMs) is the most efficient, feasible, and cost-effective method, given their status as by-products that necessitate no further processing. ...
Researchers seek sustainable materials for eco-friendly cement and concrete to reduce CO2 emissions. This paper offers an extensive overview of the research conducted on concrete technology with minimal to zero-carbon emissions. This review paper reviews materials and technologies for lowering the construction industry's carbon footprint, focusing on alternative binders and supplementary cementitious materials (SCMs). Additionally, the paper explores the transformative potential of carbon capture and utilization technologies for sustainability. It also explored life cycle assessments, economic aspects, and financial implications of this technology. Overall, the review summarizes low-carbon concrete in the context of sustainable development and climate change mitigation. It has been found that substituting SCMs for cement reduces carbon emissions in concrete without compromising strength and durability. Materials such as slag, metakaolin, calcined clay, and limestone can replace clinker, eliminating CO2 emissions in cement production. This study highlights challenges, including market adoption and material availability, offering insights for successful implementation.
... 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]. ...
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. ...
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). ...
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.
... Fine non-crystalline silica is produced as a by-product in an electric arc furnace when producing elemental silicon or alloys containing silicon. This very fine non-crystalline silica is defined as silica fume-an additive ingredient of concrete-by the American Concrete Institute (ACI) [19]. Moreover, Mercury intrusion porosimetry (MIP), a technique defining the porous structure, has shown that silica fume redistributes the pore structure of concrete paste and mortar more homogeneously by disseminating the number of large pores [20,21]. ...
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.
... 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]. ...
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]. ...
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. ...
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]. ...
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. ...
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]. ...
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. ...
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.
The prediction and monitoring of shape descriptors of pozzolans generated from ball milling processes remain today unattended by researchers. Since the particle shapes of pozzolans influence the performance of pozzolanic materials in cement-based composites, an accurate characterisation of particle shapes of pozzolans is required. In this research, we use artificial neural networks (ANNs) to predict the 2-d shape parameters of clay brick powder (CBP) particles considering various milling treatments. An integrated prediction of particle shapes is developed by combining the ANN models with image analysis. Through R values of greater than 0.96 and reduced mean square errors (MSEs) for the ANN models, it is shown that our ANN models can be able to predict the shape parameters of CBP particles under various milling treatments. Moreover, the best validations of our models are achieved at the cost of less than 5 epochs. Collectively, these results increase our understanding in the prediction of the particle shapes of CBP under various milling treatments, setting the stage for additional studies, especially in other pozzolanic materials.
This study compares the sorptivity of quaternary blended concrete with that of control concrete by utilizing several SCMs, including fly ash (FA), nano silica (NS), and metakaolin (MK). Owing to its compact structural and improved particle refinement, the quaternary blended concrete outperforms the control concrete in terms of water resistance. The increased performance was due to the addition of Supplementary Cementitious Materials (SCMs), which led to a dense and uniform microstructure, and also due to the compact interfacial transition zone. The addition of these SCMs, like flyash, decreases emissions of greenhouse gases and also solves the problem of disposal.
In the construction sector, enhancing the thermomechanical attributes of building materials is of significant importance. This research is centered on examining kaolin-enhanced rammed earth bricks, which are augmented through an alkaline solution to facilitate geopolymerization, creating a synergy between geopolymer and soil. Physico-chemical analysis methods such as X-ray diffraction (XRD), scanning electron microscopy (SEM-EDX), Fourier transform infrared spectroscopy (FTIR), differential thermal and gravimetric analysis (DTA-GTA) and particle size analysis were used to characterize the properties and reactive potential of studied materials. The chemical composition analysis revealed that the soil and kaolin contained substantial amounts of Calcite (32.2%), Quartz (26.5%), Muscovite (15.44%), Nimesite (18%), and in kaolin, Quartz (68.3%) and Illite (30.1%) were predominant. Samples with different kaolin-geopolymer ratios (0%, 3%, 4%, 5% and 6%) were designed and prepared for both mechanical (compressive and tensile strength) and thermal testing. The results obtained indicate a significant improvement in the structural integrity of earth bricks with increasing kaolin-geopolymer content when combined with an alkaline solution. However, this improvement is accompanied by a reduction in thermal resistance after 28 days.
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.
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.
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.
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
Dyslexia refers to a learning disability that affects a wide range of individuals, specifically children worldwide. Subjects with dyslexia have different experiences with recognizing the letters and the words comprising it. While several modern technologies have been envisaged for the purpose of detecting dyslexia effectively, the means to assist this learning disorder is largely inadequate till date and technical interventions in this regard have either been quite slim or the solutions presently at hand fail to take up a pragmatic approach towards dealing with the issue at hand. In this research, we have adopted an application-based efficient approach which will assist and enhance the learning process of the people who have been medically diagnosed with dyslexia. People with dyslexia tend to have problems reading text or electronic documents in the conventional font which is largely used across various resources and this invariably slows down their learning process. Dyslexia Assistant aims to address this issue and takes up multiple feasible approaches which will help enhance the visual as well as auditory perception of the concerned person with dyslexia during the course of the learning process.KeywordsDyslexiaLearningOpen DyslexicTypefaceVisual PerceptionAudio PerceptionReader
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.
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