Ordinary Portland Cement Production Research Articles

Development of eco-efficient limestone calcined clay cement (LC3) mortars by a multi-step experimental design

Calcined clays and calcium carbonates can be used to reduce clinker factor in blended cements, offering significant economic and environmental benefits. Limestone calcined clay cements (LC3) combine them as supplementary cementitious materials (SCMs) for delivering a sustainable alternative to conventional Ordinary Portland Cement products, with envisioned applications in construction and rehabilitation of historical buildings.This study reports a chemometric approach to the development of LC3 mortars, targeting to minimize clinker content while maintaining or improving the technical characteristics. To evaluate their performance, apparent density, modulus of elasticity, open porosity, water absorption, flexural and compressive strength have been considered as responses. Multiple Linear Regression (MLR) and Principal Component Analysis (PCA) were employed in a three-step mixture-process design allowing to obtain LC3 mixtures with a 21 wt% reduction in clinker while achieving notable enhancements in the physical properties (open porosity −9% and water absorption −10 %), along with commendable increases in compressive strength (+17 %) when compared to benchmark mortars produced without SCMs. The successful integration of multivariate techniques in designing sustainable building materials is showcased, highlighting the potential of chemometric methodologies to reduce the environmental impact as well as to increase the performance of building materials.

Environmental assessment of cement production with added graphene

Cement production significantly contributes to climate change, necessitating alternatives to mitigate the environmental impacts of this essential construction material. This study evaluates 18 environmental impacts of producing Ordinary Portland Cement (OPC) and Graphene (Gr) using life cycle assessment (LCA). Additionally, we explore whether mixing OPC and Gr can lower the life cycle environmental impacts of the final product (OPCGr). Our results show that OPC production in the United Kingdom generates 775 kg CO2 eq./t, 57% only from geogenic CO2 emissions. Gr production via electrochemical exfoliation in Australia results in 121,000–143,000 kg CO2 eq./t, primarily due to electricity generation. Using hydro and nuclear power (e.g., in Brazil and France) can sharply reduce these impacts (global warming potential in the range of 11,000–35,000 kg CO2 eq./t). Adding 0.02 wt% of Gr in powder form (Grpowder) from Australia to the OPC and assuming a 16.5% reduction in its usage due to increased strength, results in 674 kg CO2 eq./t OPCGr (a 13% reduction). However, some impact categories like marine eutrophication and freshwater ecotoxicity potentials increase sharply (>28%). Using Grpowder from Brazil and France further reduces the OPCGr global warming potential and the overall environmental footprint.

Mechanical and thermal properties of geopolymers derived from metakaolin with iron mine waste

The construction sector is a major contributor to the increase in energy consumption and CO2 emissions, predominantly through the production of Ordinary Portland Cement (OPC). Recent research has focused on building materials, particularly focusing on amorphous aluminosilicates such as geopolymers, with the objective of alleviating environmental impact by enhancing energy management and embracing more sustainable, cost-effective production techniques while maintaining mechanical and thermal properties. This investigation scrutinizes the mechanical and thermal properties of geopolymers based on metakaolin (MK) and incorporating iron mine waste (Hem), predominantly composed of hematite, across various proportions (ranging from 0% to 50% Hem). Diverse methodologies, including compressive strength testing, bulk density measurement, X-ray diffraction, and thermal conductivity analysis, were utilized to characterize the geopolymers. The results revealed that formulations consisting of 100%MK and 90%MK10%Hem exhibit the highest compressive strengths, measuring at 40 MPa, after a 90-day curing period. However, the most sustainable option, yielding a compressive strength of 37 MPa, is observed in the formulation comprising 60%MK40%Hem, due to its increased use of mine waste. Additionally, geopolymers incorporating higher proportions of mine waste showed reduced thermal conductivity and diffusivity. For instance, the thermal conductivity of the 100%MK geopolymer was recorded at 0.58 W/m•K, with a diffusivity of 0.46 × 10−6 m2/s, whereas the formulation containing 60%MK40%Hem displayed values of 0.46 W/m•K and 0.38 × 10−6 m2/s, respectively. These diminished values signify an enhancement in energy efficiency within buildings employing geopolymers incorporating iron mine waste.

Bond Stress Behavior of a Steel Reinforcing Bar Embedded in Geopolymer Concrete Incorporating Natural and Recycled Aggregates

The rise in greenhouse gases, particularly carbon dioxide (CO2) emissions, in the atmosphere is one of the major causes of global warming and climate change. The production of ordinary Portland cement (OPC) emits harmful CO2 gases, which contribute to sporadic heatwaves, rapid melting of glaciers, flash flooding, and food shortages. To address global warming and climate change challenges, this research study explores the use of a cement-less recycled aggregate concrete, a sustainable approach for future constructions. This study uses fly ash, an industrial waste of coal power plants, as a 100% substitute for OPC. Moreover, this research study also uses recycled coarse aggregates (RCAs) as a partial to complete replacement for natural coarse aggregates (NCAs) to preserve natural resources for future generations. In this research investigation, a total of 60 pull-out specimens were prepared to investigate the influence of steel bar diameter (9.5 mm, 12.7 mm, and 19.1 mm), bar embedment length, db (4db and 6db), and percentage replacements of NCA with RCA (25%, 50%, 75%, and 100%) on the bond stress behavior of cement-less RA concrete. The test results exhibited that the bond stress of cement-less RCA concrete decreased by 6% with increasing steel bar diameter. Moreover, the bond stress decreased by 5.5% with increasing bar embedment length. Furthermore, the bond stress decreased by 7.6%, 7%, 8.8%, and 20.4%, respectively, with increasing percentage replacements (25%, 50%, 75%, and 100%) of NCA with RCA. An empirical model was developed correlating the bond strength to the mean compressive strength of cement-less RCA concrete, which matched well with the experimental test results and predictions of the CEB-FIP model for OPC. The CRAC mixes exhibited higher costs but significantly lower embodied CO2 emissions than OPC concrete.

Effect on Sulfuric Acid Resistance and Shrinkage of Concrete Incorporating Processed Bagasse Ash and Silica Fume

Using ordinary Portland cement (OPC) in concrete has significant environmental and sustainability concerns. Notably, in the production of OPC, large volumes of greenhouse gases are produced, which contribute to global warming, and large amounts of natural raw materials are used, which can lead to the depletion of nonrenewable resources with time. In addition, OPC production is highly energy-intensive. To mitigate these concerns, it has become common practice to reduce the amount of OPC used in concrete production by partially replacing OPC with a supplementary cementitious material (SCM). Most of the SCMs used have pozzolanic properties and react with free lime in OPC to provide more cementitious material, which increases the long-term strength of concrete and also densifies the pore structure, resulting in improved durability in harsh environments. This study explored the effect of OPC on the resistance to sulfuric acid attack and drying shrinkage when OPC is partially replaced by processed bagasse ash (PBA) at dosages of up to 50%, together with 5% silica fume. Both materials are pozzolanic and are expected to react with free lime in OPC concrete to increase the strength and densify the concrete; however, with increased PBA dosage, the cement is diluted, and a reduction in strength can be expected. This study explores the benefits that can be realized, focusing primarily on sulfuric acid resistance and the reduction of drying shrinkage.

Life Cycle Assessment of Ordinary Portland Cement Production in South Africa: Mid-Point and End-Point Approaches

Several environmental impacts are associated with cement production, ranging from high greenhouse gas (GHG) levels to high energy consumption (fossil fuel and electricity) to high resource usage. Due to the growing demand for cement in the industry and limited studies in South Africa, it is essential to evaluate the environmental impact of cement production in the South African context. In this study, an analysis of the production model of South African (SA) cement plants was carried out to quantify its impacts and decipher how they consequently affect lives, resources, and the ecosystem. This study carried out a Life Cycle Assessment (LCA) of cement using both the mid-point and end-point approaches of the Life Cycle Impact Assessment (LCIA). This study carried out a cradle-to-gate analysis of 1 kg of cement produced in a typical SA plant. The result showed that for every 1 kg of cement produced, 0.993 CO2 eq was emitted into the atmosphere; 98.8% was actual CO₂ emission, and its resultant effect was global warming, which causes changes in climatic conditions. Also, 1.6 kg of 1,4-Dichlorobenzene (1,4-DCB) eq was emitted into the air and water, which caused high toxicity in these media, and for every 1 kg of cement produced, 0.139 kg of oil eq was produced, and its effect was seen in fossil resources’ scarcity. The end-point result showed that 55,404 was the potential number of human lives that could be endangered annually; 133 species had the potential to be endangered annually, and the effect of a potential scarcity of resources caused a total marginal price increase of ZAR 6.2 billion due to these damages. In conclusion, this study prescribed mitigation and adaptation strategies to counter these environmental impacts.

A comprehensive review of synthesis, characterization, and applications of aluminosilicate materials-based geopolymers

The increase in the cement industry's production, especially the production of Ordinary Portland Cement (OPC), increases the amount of CO2 released into the atmosphere, one of the main greenhouse gases responsible for global warming, with harmful effects on the environment and human health. Against this background, geopolymer concrete is a new type of inorganic polymer material that has attracted the attention of researchers in the building area, due to recycling waste by-products to replace OPC and reducing greenhouse gas (CO2) emissions during its manufacture. It also exhibits better mechanical, thermal, chemical, and electrical properties than OPC-based concrete. In the same environmental context, this material has also attracted the attention of researchers in the wastewater treatment area, because of its specific surface area and the capability of adsorption, photodegradation, and encapsulation of organic and inorganic pollutants. The principal focus of this paper is to provide an in-depth overview of the works that have been undertaken to explore geopolymer-type materials. The paper will attempt to develop a comprehensive database, based on the last research works published between 2010 and 2023 with about 247 references, which explains the elaboration, characterization, and application of these materials in several fields. Therefore, it is estimated that geopolymer composites are promising future candidates for recycling industrial solid waste, the partial or total replacement of OPCs in the construction industry, and the development of adsorbents and catalysts for wastewater treatment.

Carbon-captured sodium hydroxide solution for sustainable alkali-activated slag

The escalating impact of climate change, primarily driven by greenhouse gas emissions, has prompted global efforts to achieve carbon neutrality. Ordinary Portland cement production contributes approximately 7% to global carbon dioxide (CO2) emissions, necessitating innovative approaches for its sustainable production. A novel method is introduced that utilizes a sodium hydroxide (NaOH) solution captured with CO2 as an alkali activator for ground granulated blast furnace slag (GGBFS); it can substitute for the cement in producing construction materials. The method integrates CO2-dissolved alkaline solutions into the activation process of GGBFS, which results in the production of sustainable alkali-activated slag materials. Various concentrations of dissolved CO2 in the NaOH-based activator were used to evaluate their impact on compressive strength, setting time, and changes in phase composition. The results demonstrate that higher CO2 concentrations lead to increased compressive strength, but an excess hinders early-age strength development. X-ray diffraction and thermogravimetry analyses explain the phase changes during carbonation, emphasizing the role of CO2 in forming calcite and enhancing C-S-H production. Additionally, the study quantifies CO2 uptake, revealing a linear relationship with dissolved CO2 concentrations.

Evaluation of Properties of Concrete Without Cement Produced Using Fly Ash‐Based Geopolymer

AbstractThe use of ordinary Portland cement (OPC) in the construction industry is inevitable. The huge production of OPC and its use in infrastructural development pose an environmental impact. Greenhouse gas emitted increases the global temperature and it is an alarming sign to everybody on the planet. Concrete is the most consuming material which is produced by using OPC and it is proven that OPC contributes a lot to CO2 emission. Hence in this study attempt is made to produce concrete by using environment‐friendly material like fly ash along with alkaline activators, which is termed Geo polymer concrete. The by‐product fly ash is widely available worldwide. It is a by‐product of thermal power plants. The use of fly ash in concrete produces less expensive and more cost‐effective concrete than concrete made up using OPC. Due to its high silicate and alumina content, fly ash reacts with an alkaline solution to create an aluminosilicate gel that binds the aggregate and results in high‐quality concrete. Fly ash is finer than cement, it occupies the pores of cement after hydration. This would result in denser concrete which gives higher strength. In comparison to ordinary concrete, fly ash‐based geopolymer concrete offers better resistance to aggressive environments and high temperatures. In the present study, an alkaline activator of molarity 8 is used to prepare geopolymer concrete. The test specimens are cast and cured for 28 days. Test results indicate that an alkaline liquid fly‐ash ratio (0.4) produces higher mechanical properties. Hence, geopolymer concrete produced in this study is found to be cost‐effective and environment friendly.

Industrial by-products-derived binders for in-situ remediation of high Pb content pyrite ash: Synergistic use of ground granulated blast furnace slag and steel slag to achieve efficient Pb retention and CO2 mitigation

Ordinary Portland cement (OPC) is a cost-effective and conventional binder that is widely adopted in brownfield site remediation and redevelopment. However, the substantial carbon dioxide emission during OPC production and the concerns about its undesirable retention capacity for potentially toxic elements strain this strategy. To tackle this objective, we herein tailored four alternative binders (calcium aluminate cement, OPC-activated ground-granulated blast-furnace slag (GGBFS), white-steel-slag activated GGBFS, and alkaline-activated GGBFS) for facilitating immobilization of high Pb content pyrite ash, with the perspectives of enhancing Pb retention and mitigating anthropogenic carbon dioxide emissions. The characterizations revealed that the incorporation of white steel slag efficiently benefits the activity of GGBFS, herein facilitating the hydration products (mainly ettringite and calcium silicate hydrates) precipitation and Pb immobilization. Further, we quantified the cradle-to-gate carbon footprint and cost analysis attributed to each binder-Pb contaminants system, finding that the application of these alternative binders could be pivotal in the envisaged carbon-neutral world if the growth of the OPC-free roadmap continues. The findings suggest that the synergistic use of recycled white steel slag and GGBFS can be proposed as a profitable and sustainable OPC-free candidate to facilitate the management of lead-contaminated brownfield sites. The overall results underscore the potential immobilization mechanisms of Pb in multiple OPC-free/substitution binder systems and highlight the urgent need to bridge the zero-emission insights to sustainable in-situ solidification/stabilization technologies.

Production of an eco-friendly concrete by including high-volume zeolitic supplementary cementitious materials and quicklime

The production of ordinary Portland cement (OPC) is one of the main global causes of CO2 release to the atmosphere. However, its availability and unique characteristics as a binding material make it difficult to be substituted by eco-friendlier materials. However, OPC partial replacement with pozzolanic materials is one of the best solutions to this problem. Hence, in this study, various types of high-volume zeolite were employed as supplementary cementitious materials (SCM), substituting the OPC by up to 50 wt.% in the composition of the created mortars. Besides, quicklime and inorganic accelerators were included in some of the mortar mixtures to improve the hydration reaction and enhance its speed. The mechanical, durability and durability in sea water properties were investigated. Although the usage of SCM caused a decrease in the mechanical and durability properties of the specimens, the addition of 10 wt.% quicklime palliated this degradation by enhancing by 40% the 28-days compressive strength of the specimens and by significantly improving their durability (porosity, freeze–thaw resistance and carbonation resistance). Moreover, the mixtures were proved to be resistance to aggressive ionic environments, since their compressive strength even increased after 28-day immersion in seawater, due to the additional formation of hydration compounds.

Neural Network Predictive Models for Alkali-Activated Concrete Carbon Emission Using Metaheuristic Optimization Algorithms

Due to environmental impacts and the need for energy efficiency, the cement industry aims to make more durable and sustainable materials with less energy requirements without compromising mechanical properties based on UN Sustainable Development Goals 9 and 11. Carbon dioxide (CO2) emission into the atmosphere is mostly the result of human-induced activities and causes dangerous environmental impacts by increasing the average temperature of the earth. Since the production of ordinary Portland cement (PC) is a major contributor to CO2 emissions, this study proposes alkali-activated binders as an alternative to reduce the environmental impact of ordinary Portland cement production. The dataset required for the training processes of these algorithms was created using Mendeley as a data-gathering instrument. Some of the most efficient state-of-the-art meta-heuristic optimization algorithms were applied to obtain the optimal neural network architecture with the highest performance. These neural network models were applied in the prediction of carbon emissions. The accuracy of these models was measured using statistical measures such as the mean squared error (MSE) and coefficient of determination (R2). The results show that carbon emissions associated with the production of alkali-activated concrete can be predicted with high accuracy using state-of-the-art machine learning techniques. In this study, in which the binders produced by the alkali activation method were evaluated for their usability as a binder material to replace Portland cement, it is concluded that the most successful hyperparameter optimization algorithm for this study is the genetic algorithm (GA) with accurate mean squared error (MSE = 161.17) and coefficient of determination (R2 = 0.90) values in the datasets.

Study on energy use and carbon emission from manufacturing of OPC and blended cements in India.

The demand for production of cements is ever increasing to meet the infrastructure development globally. The energy and emission factors available for cements in most of the life cycle assessment (LCA) databases may not exactly suit for all the geographical locations. The main challenge in Indian scenario is the absence of database for LCA study. This study attempts to develop the energy and emission factors for the manufacturing of cements in Indian context. In the present study, five different cement manufacturing plants located in north, south, east, west and central zones of India are considered to assess the energy dissipation and carbon dioxide emission involved during the production of ordinary Portland cement (OPC). Most of the data is collected from the field, so that the energy and emission factors determined will be suitable for the zonal study. The study is then extended to assess the energy consumption and carbon dioxide emission for three blended cements, viz. Portland Pozzolan cement (PPC), Portland slag cement (PSC) and composite cement (CC) with permissible known replacement levels of fly ash, granulated blast furnace slag and both fly ash and slag, respectively. The average energy use and carbon emission is found to be on higher side in India by 15.14% and 12.64%, respectively, compared to other countries in manufacturing of cements. An average energy consumption in manufacturing of PPC, PSC and CC is found to be respectively 24.5%, 35.3% and 43.13% less compared to that of OPC. The CO2 emission intensity for OPC is found to vary between 893 and 940kg/tonne of cement from five different zones, and an average of respectively 24.8%, 40.97% and 47.18% lower CO2 emission was observed from PPC, PSC and CC compared to OPC. From the inventory results, CC has proven to be a more sustainable cement with low energy consumption and lower CO2 emission compared to other cements.

The Effect of Adding Barley and Oats Husks Ashes on the Properties of Ordinary Portland cement

In this scientific study, the researcher’s analysed agricultural waste materials, namely barley husk ash (BHA) and oats husk ash (OHA), as possible substitutes for ordinary Portland cement (OPC). The primary aim was to improve OPC production capacity while mitigating ecological and economic problems linked with traditional OPC production. A range of cement blends, comprising different proportions (0, 5, 10, 15, 20 and 25 wt. %) of BHA or OHA additives in OPC, were prepared and analysed.
 Raw material analysis was conducted through X-ray fluorescence technique (XRF), complying with established standards. Cement mixes, resulting from the blends, were scrutinised for their cementing properties and mechanical performance according to international standards. The properties analysed were standard water of consistency (WOC), bulk density, apparent porosity and compressive strength after a hydration period of 28 days. A 15% ash inclusion resulted in the maximum compressive strength of hardened cement pastes, specifically, a 42% increase for reinforcing with BHA (strength value rose from 358 to 510 Kg/cm3) and a 38% increase in strength value for OHA incorporation (strength value increased from 340 to 470 Kg/cm3).
 The study's findings showed that the incorporation of 15-20 wt. % of BHA or OHA led to a substantial improvement in the cementing properties examined. It is noteworthy that BHA was found to be more advantageous as cement mixes containing BHA demonstrated superior cementing properties in comparison to the other investigated samples. The superior performance of the cement blends can be attributed to the relatively higher pozzolanic nature demonstrated by BHA, which had a positive impact overall.

Effect of manufactured sand, micro silica, and GGBS on properties of high-performance concrete

The most often used building material for engineering constructions is concrete. The rapid urbanization has necessitated the need for High Strength (HS) and High -Performance Concrete (HPC) for specialized constructions, such as high rise/tall structure and other important structures. Greater cement content may be required for concrete with higher performance like strength and durability, but code does not permit it, because higher cement content increases the heat of hydration, which leads to the development of thermal cracks in concrete, reduces its structural performance and damage environment by producing CO2 during production of Ordinary Portland Cement (OPC). This study tries to replace OPC by Micro Silica (MS) and Ground Granulated Blast Furnace Slag (GGBS) by some percentage to find our effect of these materials on properties of concrete HPC.In this work, the influence of Manufactured Sand (M-Sand), Micro Silica (MS) and Ground Granulated Blast Furnace Slag (GGBS) on the mechanical and durability qualities of High - Performance Concrete (HPC) is examined experimentally. Ordinary Portland cement (OPC) is used to create the HPC mixtures and then 40%,45%, 50% by weight of OPC is replaced with GGBS and 2.5% and 5% by weight of OPC is replaced with MS respectively. Additionally, OPC is replaced by 40%GGBS+ 2.5% MS, 40% GGBS+5% MS, 45%GGBS+ 2.5% MS, 45% GGBS+5% MS, and 50%GGBS+ 2.5%MS, 50%GGBS+5% MS. For each percentage replacement workability test, compressive test at the age of 28,56 and 90 days, water permeability test at 28 days and 90 days, Scanning Elector Microscope (SEM) test after 90 days are carried out. The investigative study’s findings showed that partial replacement of OPC with GGBS, MS, and combinations of GGBS and MS produces more consistent outcomes for strength and durability when compared to control mix.

Utilization of treated water for building construction: A case study in Egypt

Due to rising living standards and population growth, saving fresh water will be a significant problem for the next generation. The Government is indirectly impacted by a significant financial burden due to the current usage of treated wastewater, in all of Egypt's districts. As a case study, Egypt's new administrative capital was chosen, given that it is today one of the most important cities and that its planning was predicated on making it a smart, sustainable city. The goal of the study was to develop methods for replacing potable water in the manufacture of concrete with tertiary-treated wastewater; however, used for concrete mixing or curing after concrete hardening. Property assessments of the fresh and hardened concrete were conducted, to ascertain the best water quality that can be used without compromising the quality or durability of the concrete. ; The results of this paper will serve as a guide for decision-makers looking to decrease costs and increase sustainability by using treated wastewater in making sustainable concrete for buildings, especially in recent decades, rising construction material usage has generated considerable environmental difficulties, particularly in the production of Ordinary Portland cement (OPC).

Effect of coconut shell ash substitute with cement on the mechanical properties of cement concrete

The production of ordinary portland cement results in a great amount of carbon dioxide emissions, which has serious consequences for the environment. The building industry has been urged to make use of soil waste from industries or secondary materials in order to cut down on the amount of natural raw materials needed to make cement and concrete. Increases in population, economic activity, and social progress have all contributed to a rise in global garbage output. The investigation of waste reduction and reuse is one of the most alluring possibilities for handling such waste. It is becoming increasingly unaffordable to use cement in concrete works, despite the fact that the demand for homes and other constructions that rely on this material continues to rise in combination with the expansion of the human population; as a result, it is necessary to identify and develop alternative binding materials that can be used either wholly or partially in place of cement. In order to produce coconut shell ash (CSA), an agricultural waste material and environmental pollutant that is used as pozzolana in partial replacement of cement in the production of concrete, coconut shells are collected, burned in the open air (uncontrolled combustion) for three hours, and then incinerated in a muffle furnace at 800oC for seven hours. On the order of 0%, 5%, 10%, 15%, 20%, and 25% OPC was replaced with CSA in the concrete used to cast the specimens. Coconut shell ash is a viable cement replacement. The impact of CSA on mechanical qualities was investigated using a range of coconut shell ash replacements.

Recovery of ultra-high purity reactive magnesia from reject brine and its comparison with commercial magnesia

CO2 emissions and energy consumption associated with ordinary Portland cement production have increased the urgency for the development of alternative construction materials. Reactive magnesia cement (RMC) has been widely studied in the recent years due to the lower calcination temperature used during its production and its ability to permanently sequester CO2. In addition to the calcination of magnesite, reactive MgO, the main component of RMC, can also be synthesized from reject brine, which is rich in Mg2+. However, the presence of other components such as calcium in reject brine leads to the precipitation of other mineral phases together with Mg(OH)2, thereby reducing the purity of the final product. With the goal of improving the purity and yield of MgO synthesized at the end of this process, this study proposed a selective precipitation approach under a controlled pH. An optimum condition was determined for the synthesis of magnesium oxalate dihydrate with an ultra-high purity of 99.6 % and a high magnesium recovery rate of 94.1 %. Reactive MgO with a specific surface area of 30.2 m2/g was obtained after the calcination of the synthesized magnesium oxalate dihydrate at 700 °C for 2 h, which was higher than some of the commercially available MgO powders.

Novel Amorphous-Wollastonitic Low-Calcium Hydraulic Binders: A State-of-the-Art Review.

Because of the severe environmental impact of the CO2 emissions associated with the production of ordinary Portland cement (OPC) and the increasing demand for this commodity material, the development of alternative products has become a global concern. One alternative to OPC, or alitic-based clinkers, are amorphous-wollastonitic low-calcium hydraulic binders (AWLCs). This new class of hydraulic binders, described in the literature for the first time in 2015, may significantly reduce the CO2 emissions associated with its production, resulting from its lower calcium content, but also from the fact that its production technology can be fully electrified. In this paper, a state-of-the-art review is presented, providing a comprehensive description of the latest research, summarizing both the physicochemical and mechanical characteristics of this type of hydraulic binder, as well as possible routes for its production at an industrial scale.

Assessment of Use of Pozzocrete on Strength of Concrete

Abstract: Concrete demand has increased to satisfy the need of infrastructural development facilities. Tremendous amount of natural resources and energy is consumed for production of ordinary Portland cement. It also emits substantial quantity of carbon dioxide into the atmosphere. Therefore, it has been need of the hour to find out alternatives for making eco-friendly concrete. Many siliceous and alumnio-siliceous material are available which possess little or no binding values. But these materials in finely divided forms when come in contact with moisture, they chemically react with calcium hydroxide to form compounds those have binding properties. In the current studies when research was conducted on pozzocrete in laboratory it was well established that when pozzocrete is used in concrete, it increases the strength of concrete. Pozzocrete being finer than cement, gives more specific surface, fills the voids, increases workability of concrete and also reduces the problem of shrinkage in concrete. In the current study, the behavior of pozzocrete with cement concrete is reported. Percentage variation of pozzocrete in cement concrete to replace cement is tested to achieve economy as well as higher strength of RCC structural members. An experimental investigation was carried out on pozzocrete in reinforced cement concrete. Weigh batching method was used for 10% to 30% replacement of cement by pozzocrete in M20 grade concrete. It was found out that 30% replacement of cement with pozzocrete gave most acceptable results in flexural behavior. Workability and ductility of concrete was also found to be increased with increase in flexural strength.