Optimized Hybrid Learning Model for Strength Prediction of Textile Effluent Sludge‐Based Concrete

Combined effects of supplementary cementitious materials (silica fume, GGBS, fly ash and rice husk ash) and steel fiber on the hardened properties of recycled aggregate concrete

This research focuses on studying the effect of different supplementary cementitious materials (SCMs) such as waste ceramic powder (WCP), lime powder (LP), and ground granulated blast furnace slag (GGBS) in combination on strength characteristics and microstructure of quaternary blended high‐strength concrete. To achieve the aims of the study, necessary physical and chemical composition tests were done for the raw materials. Then, mixes were designed into control mix with 100% Ordinary Portland Cement (OPC) and experimental mixes containing 30%, 40%, 50%, and 60% of GGBS, WCP, and LP in combination. Tests were conducted during casting and at curing ages of 7 and 28 days. Accordingly, the control mix which is concrete grade 50 (C‐50) as per American Concrete Institute (ACI) mix design is used as a reference for comparison of test results with those specimens produced by partial replacement of SCMs. The characterizations of high‐strength concrete are done using consistency, setting time, workability, compressive strength, flexural strength, and morphological tests. The optimum percentage replacement is 50% OPC replacement by 30% GGBS + 10% WCP + 10% LP. Based on the experimental investigations, the workability increases as the replacement level of SCMs increases from 30% to 60% by weight. Compressive strength and flexural strength results increase up to 11.41% and 20% when the percentage replacement increases from 30% to 50% of SCMs replacement at 28 days of curing time, respectively. There are also improvement in the microstructure and significant cost saving due to replacing OPC partially with SCMs with proportions mentioned above. Therefore, the practice of utilizing increased percentage of SCMs in quaternary blend in concrete can be beneficial for the construction industry and sustainability without compromising the quality of the concrete product.

This investigation aims to examine the behavior of natural and manufactured pozzolans, as well as the properties of blended mortars. Eco-friendly building materials are gaining the attention of researchers worldwide, as they are made from supplementary cementitious materials that alter the fresh and mechanical properties of the blended mortar. Granulated blast furnace slag, silica fume, zeolite powder, metakaolin, clay powder, fly ash, rice husk ash, copper slag, and glass powder have all been used to improve the microstructure, workability, setting time, and strength. The control mixes contain a range of replacement rates (5–50 %) as supplementary cementitious materials compared to the OPC reference mortar. Brick clay powder (5–15 %), Granulated Blast Furnace Slag (5–20 %), Silica Fume (5–25 %), Copper Slag (5–35 %), Metakaolin (5–25 %), Fly Ash (5–30 %), Rice Husk Ash (5–20 %), Zeolite Powder (5–20 %), Ceramic Waste (5–35 %) and Glass Powder (5–10 %) were identified as the beneficial proportion. Moreover, strength increases simultaneously with the volume/index of the big content of all supplementary cementitious materials blends, but beyond the critical level of supplementary cementitious materials mixes, it tends to reduce strength. The changes made by integrating supplementary cementitious materials are significant in terms of both the fresh and hardened properties of blended mortar.

Performance of self-compacting concrete with treated rice husk ash at different curing temperatures

Expanding the world’s infrastructure drives up demand for building materials, particularly ordinary Portland cement (OPC) concrete, whose high carbon dioxide (CO2) emissions have a detrimental effect on the environment. To address this issue, researchers looked into employing alternative supplementary cementitious materials (SCMs), including metakaolin (MK), which is derived from calcined kaolin clay with pozzolanic properties, to partially or completely replace OPC in concrete. This review article examines the MK’s application in alkali-activated materials (AAMs) and OPC-based concrete. By interacting with calcium hydroxide, MK functions as a pozzolanic additive for OPC concrete, enhancing its mechanical qualities and durability. The use of MK as a source material in AAMs, a newly developed class of sustainable binders, is also covered in this article. The effects of different combinations of MK with additional SCMs, including fly ash (FA), ground granulated blast furnace slag (GGBFS), silica fume, and rice husk ash, on the characteristics of alkali-activated concrete both in its fresh and hardened states, are compiled. The majority of the articles considered in this study are from the past decade, while some relevant articles from 2014 and earlier are also taken into account. The results showed that adding MK to concrete in combination with FA or GGBFS has excellent synergistic effects on microstructural development, pozzolanic activity, and strength increases. In particular, the MK–FA mix demonstrated the most encouraging performance gains. Because of its large surface area, the use of nano-MK helped achieve a denser geopolymer structure and improve mechanical properties. The best curing temperatures for MK-based geopolymers to gain strength were found to be between 40 and 80°C for a total of 28 days. The review also pointed out that the compressive strength and geopolymerization process of MK-based geopolymers were enhanced by increasing the mass ratio of Na2SiO3 to NaOH and NaOH concentration. Nevertheless, geopolymerization was hampered by unnecessarily high alkali concentrations. Moreover, the compressive strength was increased by partially replacing MK with TiO2 or GGBFS. The synergistic effects of combining MK with other SCMs to improve concrete performance highlight the potential of MK-based solutions in lowering the environmental footprint of concrete buildings.

Role of binary cement including Supplementary Cementitious Material (SCM), in production of environmentally sustainable concrete: A critical review

The demand for concrete is increasing day by day due to vast development in urbanisation. One of the important ingredients to manufacture concrete is cement whose production is leading to large amount of carbon dioxide (CO2) releases attributing to global warming. To reduce the usage of cement in concrete, Supplementary Cementitious Materials (SCM) are given importance and plenty of research is done on them. SCM’s can replace cement upto permissible limits and enhance the concrete properties. The concretes that can replace the cement content completely are Geo Polymer Concrete (GPC) and Alkali Activated Concrete (AAC). They are eco-friendly concretes in which the wastes coming from various types of industries, treatment plants and agro wastes can be used as binders. Alkaline activator solution is used to activate the binder materials which is a combination of silicates and hydroxides. GPC and AAC has wide range of applications like making of concrete benches in park, balusters, paver blocks and non-load bearing components etc. In this paper, a novel mix design for AAC for a constant alkaline solution to binder ratio of 0.4 is presented. The molarity of sodium hydroxide used in this study is 10M. Various mix combinations of binders using Fly ash, Ground Granulated Blast Furnace Slag (GGBS) and Rice husk ash (RHA) were considered. Workability, Physical and mechanical properties of AAC mixes were determined including Non-Destructive tests (NDT). Mixes with RHA resulted in poor compressive strength as the water demand was high and curing under ambient conditions proved to be of low impact especially for AAC with RHA.

Over the years, supplementary cementitious materials (SCM) have been successfully utilized in concrete buildings, but they have been rarely exploited in concrete pavements. In recent years, due to the growing importance of concrete pavements, researchers have begun studying the performance of various types of SCMs from pavement perspective. The overview herein assesses the existing research associated with utilizing different kinds of silica-rich waste as SCM. For this purpose, five agricultural waste (AW) comprising rice husk ash (RHA), rice straw ash (RSA), corn cob ash (CCA), palm oil fuel ash (POFA), sugarcane bagasse ash (SBA) and three industrial by-products (IB), i.e., fly ash (FA), ground granulated blast furnace slag (GGBFS) and microsilica (MS), were selected. Their effects on various properties of concrete were exhaustively reviewed. This study also furnishes reasons for limited literature on SCMs utilization in concrete pavements. Moreover, this review accentuates the previous studies' gaps, which require further research, such as the need for dedicated standard codes for AW utilization in concrete pavements. The guidance for future research to further enhance the properties of pavement quality concrete is also given.

Establishing the carbonation profile is of great significance to the prediction of the service life of reinforced concrete structures. In our previous work, Raman spectroscopy was shown to be an efficient tool for characterizing calcium carbonate (CaCO3) polymorphs and their profile in plain Portland cement (PC) matrices. However, as supplementary cementitious materials (SCMs), particularly fly ash (FA) and ground granulated blast furnace slag (GGBS), are widely used in concrete, establishing the carbonation profile without considering the possible effects of these SCMs could be of little significance to the real world. This paper, thus, investigated the effects of FA and GGBS on the working capacity and reliability of Raman spectroscopy for establishing the carbonation profile in PC blends containing SCMs. The thermogravimetry (TG) analysis was also conducted to verify the results from Raman spectroscopy. The results show that Raman spectroscopy demonstrated a good capacity for differentiating the variation of CaCO3 contents in FA or GGBS blends. However, the incorporation of FA and GGBS into the PC system caused some adverse effects on the quantification of CaCO3 by Raman spectroscopy, which could be attributed to the darker color and weak scatter nature of FA and the high content of glassy phases in GGBS.

The effect of different amounts of supplemental cementitious materials (SCMs) on the physical and mechanical characteristics of lightweight concrete is examined in this study. SCMs include Fly Ash, Rice Husk Ash (RHA), Ground Granulated Blast-furnace Slag (GGBS), and Silica Fume. Cube crushing strength, flexural strength, density and water absorption tests were performed on eight mix proportions. The current study also established that, when 20% Fly Ash was incorporated in the concrete as a replacement, the compressive strength was 30 MPa and the flexural strength was 4 MPa, the highest compressive strength of 32 MPa and the flexural strength of 4.2 MPa were however obtained when 20% Silica Fume was incorporated in the concrete as a replacement. In the present study only small increment in water absorption was recorded for mixtures containing GGBS and RHA while Fly Ash and Silica Fume shown relatively less water absorption than the control specimen. So, according to the results obtained Fly Ash and Silica Fume are good additives to lightweight concrete since the material becomes more stronger and durable and at the same time has low density.

Ultra-high performance concrete (UHPC) refers to cement-based materials exhibiting com- pressive strength higher than 120 MPa, high ductility, and excellent durability. High cracking tendency of UHPC derived from autogenous shrinkage can be a concern due to its high binder content and low water to binder ratio (w/b). This paper reviewed early hardening, microstructure, and shrinkage develop- ment of UHPC. The effect of supplementary cementitious materials (SCMs), such as silica fume (SF), ground granulated blast furnace slag (GGBS), fly ash, limestone powder, rice husk ash, and nano-mate- rials, and curing methods on hydration and microstructure was reviewed. In addition, the effect of cement, water content, aggregate, chemical admixtures, SCMs, curing methods, and fiber on the shrinkage of UHPC was summarized. Different methods to compensate and/or reduce the early-age shrinkage of UHPC were introduced.

Abstract: With the exponential growth of industrialization, industrial by-products are also increasing day by day. One of the byproducts of the steel industry is ground granulated blast furnace slag (GGBS). In addition, GGBS is a good cement mortar due to its durability and strength, and glass waste is a waste material that can replace cement. After 28 days, the pozzolanic reaction between cement hydration and glass powder showed that cement replacement did not affect the compressive strength of concrete. The use of GGBS and waste glass powder (WGP) is the focus of this article. In this experiment, slag (GGBS) and mineral additive (WGP) were used instead of cement by weight. To examine the differences in concrete properties, the differences between glass powder and GGBS were added to the cement. The results regarding air entrainment were compared with partial replacement of glass powder and GGBS. We examined the strength of concrete with the addition of WGP (5%, 10%, 15%, 20%& 25%) to the M40 mixture. Additional cement can be replaced with additional materials such as 40 with GGBS (5%, 10%, 15%and 20% weight cement) at the desired WGP percentage change. Splitting tensile strength, flexural strength and compressive strength tests were conducted. The tests showed that the combination with one sample had better effect than the combination model.

As the second most used material after water and the producer of 8%–9% of anthropogenic greenhouse gas (GHG) emissions, concrete is a key target for environmental sustainability efforts. Of these efforts, a main focus has been the use of industrial byproducts as supplementary cementitious materials (SCMs) to replace some of the cement binder, the source of most of the GHG emissions from concrete production. As byproducts, these SCMs are frequently assumed to have limited or no emissions from production. Our goal is to see if this assumption should continue to drive mitigation efforts and to arrive at a clearer understanding of the contribution of SCMs to the environmental impacts of concrete. Needing further examination are: (1) how environmentally beneficial SCMs are if some of the primary process impacts are attributed to them rather than considering them waste products; (2) whether transporting SCMs creates greater environmental impacts than the materials they are replacing; and (3) whether location of primary processes that result in SCMs as well as location of concrete production creates particular burdens on lower income and minority communities. This work focuses on three of the most common industrial byproduct SCMs, namely silica fume, fly ash (FA), and ground granulated blast furnace slag (BFS), exploring both GHG and particulate matter emissions. We show that allocation of impacts from primary processes dramatically increases emissions attributed to SCMs. High levels of transportation of FA and BFS typically do not result in these SCMs having higher GHG emissions than a 95% clinker-content Portland cement. We find that SCMs may be produced in areas with low income or minority populations then used to lower GHG emissions concrete in another location. As such, beyond common environmental impact assessment methods, the role of environmental justice should be incorporated into impact assessments.

The construction industry is a major contributor to global environmental impacts, particularly through the production and use of cement-based materials. In response to this challenge, this study provides a comprehensive synthesis of recent advances in the integration of Life-Cycle Assessment (LCA) and Artificial Neural Networks (ANNs) for optimizing cementitious composites containing Supplementary Cementitious Materials (SCMs). A total of 14 case studies specifically addressing this topic were identified, reviewed, and analyzed, spanning various binder compositions, ANN architectures, and LCA frameworks. The findings highlight how hybrid ANN–LCA systems can accurately predict mechanical performance while minimizing environmental burdens, supporting the formulation of low-carbon, high-performance cementitious composites. The diverse SCMs explored, including fly ash, slag, silica fume, waste glass powder, and rice husk ash, demonstrate significant potential for reducing CO2 emissions, energy consumption, and raw material depletion. Furthermore, the systematic comparative matrix developed in this work offers a valuable reference for researchers and practitioners aiming to implement intelligent, eco-efficient mix designs. Overall, this study contributes to advancing digital sustainability tools and reinforces the viability of ANN–LCA integration as a scalable decision-support framework for green construction practices.

Australia consumes approximately 29 million m3 of concrete each year with an estimated embodied carbon (EC) of 12 Mt CO2e. High consumption of concrete makes it critical for successful decarbonization to support the achievement of ‘Net Zero 2050’ objectives of the Australian construction industry. Portland cement (PC) constitutes only 12–15% of the concrete mix but is responsible for approximately 90% of concrete’s EC. This necessitates reducing the PC in concrete with supplementary cementitious materials (SCMs) or using alternative binders such as geopolymer concrete. Concrete mixes including a combination of PC and SCMs as a binder have lower embodied carbon (EC) than those with only PC and are termed as low-carbon concrete (LCC). SCM addition to a concrete mix not only reduces EC but also enhances its mechanical and durability properties. Fly ash (FA) and granulated ground blast furnace slag (GGBFS) are the most used SCMs in Australia. It is noted that other SCMs such as limestone, metakaolin or calcinated clay, Delithiated Beta Spodumene (DBS) or lithium slag, etc., are being trialed. This technical paper presents a methodology that enables selecting LCCs with various degrees of SCMs for various elements of bridge structure without compromising their functional performance. The proposed methodology includes controls that need to be applied during the design/selection process of LCC, from material quality control to concrete mix design to EC evaluation for every element of a bridge, to minimize the overall carbon footprint of a bridge. Typical properties of LCC with FA and GGBFS as binary and ternary blends are also included for preliminary design of a fit-for-purpose LCC. An example for a bridge located in the B2 exposure classification zone (exposed to both carbonation on chloride ingress deterioration mechanisms) has also been included to test the methodology, which demonstrates that EC of the bridge may be reduced by up to 53% by use of the proposed methodology.