Partial Replacement Of Portland Cement Research Articles

The Effects of Partial Replacement of Ground Granulated Blast Furnace Slag by Ground Wood Ash on Alkali-Activated Binder Systems.

Cement production contributes significantly to carbon dioxide emissions. Alkali-activated materials offer an environmentally friendly alternative due to their comparable strength, durability and low-carbon emissions while utilizing wastes and industrial by-products. Wood ash is a waste material that shows promising results as a partial replacement for Portland cement and precursors in alkali-activated systems. The aim of this study was to examine the effect of ground wood ash on the mechanical properties of alkali-activated mortars. Wood ash was incorporated as a 0 wt%, 10 wt% and 20 wt% partial replacement for ground granulated blast furnace slag (GGBFS). The wood ashes were ground in a planetary ball mill for 10 and 20 min. Sodium silicate (Na2SiO3), sodium carbonate (Na2CO3), and sodium hydroxide (NaOH) were used as alkali activators. The results demonstrated that ground wood ash improved the mechanical properties of alkali-activated systems compared to untreated wood ash. However, the incorporation of wood ash increased the porosity of the binder matrix.

Production of eco-friendly UHPC with high durability and resistance to harsh environmental conditions using copper mine tailings

In recent years, constructing environmentally friendly buildings, also known as green buildings, has become a crucial aspect of sustainable development principles. This experimental study investigates the partial replacement of Portland cement with Sungun copper mine tailings (SCMT) for the production of eco-friendly UHPC. The research includes resistance testing against sulfate attack at a 5% Na2SO4 concentration at 30, 90, and 180 days, with SCMT replacement ratios ranging from 5% to 30%. Furthermore, the mechanical properties of eco-friendly UHPC are examined. The study also assesses the mass loss and compressive resistance of UHPC after exposure to an HCl acid solution for 30 and 90 days. The resistance of UHPC to chloride penetration is evaluated using the rapid chloride migration test (RCMT). Additionally, capillary water absorption and microstructural properties of eco-friendly UHPC are studied through SEM analysis. The results indicate that UHPC with partial cement replacement by SCMT had improved mechanical properties, durability, and microstructure. The compressive strength reduction in eco-friendly UHPC mixtures due to acid attack was minimal when 10% SCMT was used as a replacement for cement after being immersed in HCl acid for 90 days. Furthermore, the mixture that contained 10% SCMT demonstrated lower penetration for chloride ions, Which referred to an improvement of 17.6%, compared to the control mixture. In addition, the results of the tests demonstrated that the incorporation of SCMT in UHPC at a rate of 5%–15% had a beneficial impact on the resistance of UHPC to sulfate attack when exposed to a 5% Na2SO4 concentration. This study demonstrates the potential of sustainable UHPC production with SCMT as a suitable alternative to cement in aggressive environments containing acids, sulfates, chlorides, and similar compounds.

Study of obtaining MO2C by gas-solid reaction in a fixed and rotating bed reactor

In the present study, it was decided to use ground almond shell ash instead of its shell. The main objective of this study was to investigate the feasibility of partially replacing cement with ground almond shell ash, RCA, in the production of mortars (1.5% and 5%). The flexural strength and compressive strength at 3, 7, 14, 28 and 41 days was taken into consideration. It was found, in general, that the flexural strength increased with the partial replacement of Portland cement by CCA up to 15 days, and the compressive strength decreased at each of the analyzed ages.

Mortar and concrete with lime-rich calcined clay pozzolana: A sustainable approach to enhancing performances and reducing carbon footprint

Low environmental impact sustainable building materials have become a crucial requirement and challenges to the contemporary construction industry. This study is an extensive effort for the development of a green cementitious composite to limit extensive extraction and consumption of nonrenewable mineral resources and CO2 emission generation by the reduction of clinker cement production. In this route, 10%, 25%, 35%, and 50% of CaO-based calcined clay were adopted as a partial replacement for ordinary Portland cement (OPC) in mortar mix. The raw clay was extracted from Nizwa city (NZS) and ground into particles with size less than 75 µm. As per its chemical composition, the clay was classified as cementitious and pozzolanic material as per ASTM C618 standard specifications. The mill was then calcined at different temperatures of 950 °C, 850 °C, and 750 °C. The blend mortar mixes were assessed in terms of their mechanical, microstructural, durability, and thermal performances using various experimental tests. The results indicated that replacement levels of lime-rich calcined clay varying from 10% to 35% of OPC could generally offer similar to better strengths, durability, and thermal performances to a plain mortar. The mortar flow was reduced when incorporating calcined clay, while density was unaffected. Meanwhile, CaO-based calcined clay generally exhibited better performance with regard to permeable voids, combined sulphate + chloride, sulfuric acid attacks, and chloride ions permeability. The outcome of the present work sheds light on the massive potential of calcined clay pozzolana to develop sustainable, affordable, and locally produced blend cement for a variety of infrastructure applications, including energy-efficient and sustainable development, to reduce the carbon footprint.

Study on the feasibility of partial replacement of cement with IOT in extruded concrete roof tiles production

The use of mining waste (IOT) as supplementary materials for cement has the potential to significantly reduce carbon emissions, helping to mitigate the demand for natural resources and the impacts associated with their production.Concrete tiles have been gaining prominence in recent years due to practicality, aesthetics, weather resistance, attractive price, ease of fitting and useful life, however, there is no information in the literature about the effect of IOT as a pozzolanic material for partial replacement of Portland cement in these composites. Therefore, this study aims to expose the use of iron ore tailing (IOT) as a partial replacement for Portland cement in extruded concrete tiles in different proportions, qualifying and classifying them according to the marketing standards. The performance of concrete roof tiles using IOT was analyzed for bulk density, dry weight, apparent porosity, water absorption, wettability, breaking load, impact strength, coefficient of restitution, and thermal conductivity. In addition, microscopy and X-ray diffraction examined interactions between IOT particles and cementitious matrix at 28 days and after accelerated aging. Economic analyses regarding the effect of using IOT on the final cost of concrete roof tiles were also performed. The results showed that the concrete roof tiles produced with IOT presented suitable physical, mechanical, and thermal properties, highlighting the samples with 10% IOT as a replacement for cement, which proved superior to conventional tiles for the breaking load at 28 days, also presenting an average value reduction of 6.61% for porosity and 33.33% for wettability. All formulations were approved for breaking load according to the international marketing standard and may cut costs for companies producing cement roof tiles by up to 40%. In addition to reducing the potentially harmful waste in containment dams, IOT may lessen the demand for Portland cement and, consequently, CO2 emissions, producing more sustainable composites with significantly reduced manufacturing costs.

Performance of biochar mixed cement paste for removal of Cu, Pb and Zn from stormwater

Using biochar as a partial replacement of Portland cement in cementitious materials is a promising solution to mitigate negative environmental impacts. However, current studies in available literature primarily focus on the mechanical properties of composites made with cementitious materials and biochar. Therefore, this paper reports the effects of the type of biochar, the percentage of biochar addition, and the particle size of the biochar on the removal efficiency of Cu, Pb, and Zn, as well as the effect of contact time on the removal efficiency of Cu, Pb, and Zn, along with the compressive strength. The peak intensities of OH−, CO32− and Calcium Silicate Hydrate (Ca–Si–H) peaks increase with increasing biochar addition levels, reflecting increased hydration product formation. The reduction of particle size of biochar causes the polymerization of the Ca–Si–H gel. However, no significant changes were observed in heavy metal removal, irrespective of the percentage of biochar addition, the particle size of biochar, or the type of biochar added to the cement paste. Adsorption capacities above 19 mg/g, 11 mg/g and 19 mg/g for Cu, Pb and Zn were recorded in all composites at an initial pH of 6.0. The Pseudo second order model best described the kinetics of the Cu, Pb, and Zn removal. The rate of adsorptive removal increases with the decrease in the density of the adsorbents. Over 40% of Cu and Zn were removed as carbonates and hydroxides through precipitation, whereas over 80% of Pb removal was via adsorption. Heavy metals bonded with OH−, CO32− and Ca–Si–H functional groups. The results demonstrate that biochar can be used as a cement replacement without negatively impacting heavy metal removal. However, neutralization of the high pH is needed before safe discharge.

Development of a low-carbon binder based on raw, ground, and carbonated waste paper fly ash

The formulation of an eco-binder only makes sense if the technical and environmental suitability of new waste material have been assessed. This study focuses on the recovery of three sets of waste paper fly ash (WPFA): raw, ground, and carbonated, as the main component of an eco-binder. The effect of the partial replacement of ordinary Portland cement (OPC) with WPFAs is studied from a mechanical and environmental point of view. The results show that raw WPFA contributes to the development of compressive strength, especially for low substitution rates (10 and 20%). Grinding results in improved compressive strength, fineness, and stability (at high substitution rates), and also accelerated setting kinetics. Natural carbonation is an effective and low-cost solution that has been proposed to treat WPFA before incorporation into the cementitious matrix. The carbonation contributes to delaying the setting and improving the stability of the matrix. Furthermore, the process of carbonation has been observed to have a beneficial impact on the stabilization of barium through the reduction of its leaching potential, which can contribute to the environmental sustainability of the eco-binder. In conclusion, the replacement of OPC with 20% of carbonated WPFA can save significant amounts of greenhouse gas emissions (27.29%).

Effect of rice husk ash as partial replacement of ordinary Portland cement in ultra-high-performance glass concrete

Ultra-high-performance concrete (UHPC) is a high-tech concrete whose excellent mechanical and durability characteristics are ascribed to the homogeneity and high packing density of its matrix. However, due to the high contents of cement and silica fume usually necessaries for achieving this packing density, UHPC's final cost and carbon-footprint are far higher than standard concretes. Therefore, over the last few years, the spotlight of UHPC’s research has focused sharply on the analysis of locally available supplementary cementitious materials as partial replacement of cement and silica fume. This article presents an investigation to analyze the effect of rice husk ash (RHA) as partial substitution of cement in a previously optimized mixture of recycled-glass-UHPC by means of several statistical tools. Cementitious materials employed in this research involved silica fume, limestone powder, recycled glass powder and ordinary Portland cement (OPC). Based on the results, it can be concluded that RHA addition in the optimized glass UPHC yields to a significant decrease in the workability of concrete and a slight decrease of compressive strength. Results also demonstrated the high interaction between the RHA and water contents, which could be ascribed to the water absorption and internal curing provided by RHA particles.

AI-Assisted optimisation of green concrete mixes incorporating recycled concrete aggregates

Maximising the content of supplementary cementitious materials as a partial replacement for Portland cement and using recycled concrete aggregates as a full or partial replacement for coarse aggregates are among the widely adopted strategies in the design of green concrete. However, the synergetic implications of adopting both approaches on concrete properties add complexity to the design of green concrete mixes. This paper proposes a novel AI-based multi-objective optimisation framework addressing the lack of a systematic method to formulate these concretes and solves the common multi-objective mix design problems. The framework is developed for the mix proportioning of green concrete mixes containing recycled concrete aggregates and commonly used supplementary cementitious materials while considering the desired compressive strength. The proposed optimisation model leverages a dataset of about 2,120 mixes and employs an extreme gradient boosting machine to model the compressive strength requirements as a mechanical constraint throughout the optimsiation process. Moreover, a set of key environmental objectives, including minimising global warming, acidification, fossil fuel depletion potentials, and the cost of production, are targeted. The effectiveness of the framework is validated through case studies across different strength ranges. The results indicate a significant improvement in environmental sustainability indicators, including a 19.6% and 21.6% reduction in global warming and acidification potentials, besides considerable cost savings of up to 23.7% without compromising the mechanical performance of concrete.

Cow Dung Ash in Mortar: An Experimental Study

This study investigated the impact of using cow dung ash (CDA) as a partial replacement for ordinary Portland cement (OPC) in mortar. Mortar mixes are prepared by replacing OPC with CDA at varying levels: 5%, 10%, 15%, 20%, 25%, and 30%. The chemical composition of CDA shows that it is composed primarily of SiO2, Al2O3, and Fe2O3, with a significant amount of loss of ignition. The workability, hardened properties, and microstructure of CDA-containing mortars are also analyzed. The increasing CDA content in mortar reduces workability and, beyond 5%, it causes high water absorption due to CDA’s porous nature and unremoved organic compounds. This impacts the density and compressive strength of the hardened mortar as well as compromising its homogeneous characteristics. When using 5% CDA, the bulk density and compressive strength of the mortar are comparable to those of the control mixes. Nonetheless, as the proportion of CDA increases, both the bulk density and compressive strength of the mortar diminish. The thermal stability of mortar mixes with 10%, 20%, and 30% CDA is unaffected at temperatures between 500 °C and 600 °C. The Fourier-transform infrared spectroscopy (FTIR) analysis reveals the presence of unreacted particles and wide stretched C–S–H gels in the mortar samples. In general, the results suggest that CDA can be utilized as a substitute for OPC at a ratio of up to 10% in the manufacturing of mortar and can serve as a feasible alternative cementitious material.

Durability analysis of partial replacement of ordinary Portland cement by white glass waste concrete

Concrete consists of cement, water, fine aggregate, coarse aggregate, and air. The cement manufacturing process is responsible for a large carbon dioxide emission. Therefore, several research have been conducted to find advantageous substitute materials, even if only partially. Waste glass emerges as an alternative because it is a non-biodegradable inert material, with a high recycling rate and low cost. Several studies on recycled glass as a partial substitute for cement in concrete have already been conducted in terms of workability, strength, and properties, but few have reviewed the durability properties of concrete incorporating glass waste. It is a fact that durability is of great importance for the performance of concrete, because compromising it can lead to the emergence of pathologies. This article aims to carry out a study on the durability of concrete with the replacement of cement by glass waste, to verify its performance in relation to conventional concrete, identifying the advantages that attest to its use in civil construction as an alternative to concrete to be used in buildings, whether in new constructions or in the process of rehabilitation or maintenance.

A small-scale thermogravimetric method to measure the chemical reactivity of supplementary cementitious materials

Partial replacement of ordinary portland cement (OPC) with supplementary cementitious materials (SCMs) is a ubiquitous and effective approach to design concrete mixtures with lower embodied carbon and improved durability compared to plain OPC concrete mixtures. However, the global supply of common industrial SCMs, like fly ash (a byproduct of coal combustion) and blast-furnace slag (a byproduct of steelmaking), is dwindling due to global decarbonization efforts and sustained demand from the concrete industry. The newly standardized ASTM C1897 rapid, relevant, and reliable (R3) test is an effective screening method to measure the chemical reactivity of potential SCMs. However, the sample quantity requirements impede the rapid-throughput screening of new SCM sources that may currently be available only in small quantities. The objective of the current study is to design and validate a small-scale modified R3 test to enable standardized characterization and rapid-throughput screening of novel SCMs. The results substantiate that the ASTM C1897 R3 bound water method can be performed with sufficient accuracy at a much smaller scale (i.e., 0.01 g of SCM per test) using the thermogravimetric method developed and validated herein.

Using diatomite as a partial replacement of cement for improving the performance of recycled aggregate concrete (RAC)-Effects and mechanism

This work proposes that diatomite can be used to improve the performance of recycled aggregate concrete (RAC). A calcined diatomite sample with an amorphous silica content over 90% was added to the RAC mixture as a partial replacement of the ordinary Portland cement (OPC) at varying rates from 0 to 20 wt%. Test results show that both the strength and impermeability of RAC can be obviously enhanced with the greatest enhancement observed at a replacement level of 15 wt% for which the 28-day compressive/splitting tensile strengths were improved by 29.2% and 33.9%, respectively, and the chloride diffusion coefficient was reduced by 86.27%. The microscopic measurements confirmed the nucleation effects and the high pozzolanic reactivity of diatomite which both contributed to the more complete hydration of cement in RAC. It was also found that the proportion of large capillary pores in the new mortar was reduced by using diatomite, meanwhile the average porosity of the new interfacial transition zone (ITZ) became smaller. This work suggests that the calcined diatomite used for improving RAC performance should be no larger than 15 wt% of cement, as the scarcity of CH at a higher replacement ratio would hamper the pozzolanic reactions, meanwhile the diluted cement clinkers would have a negative effect on the pore structure of RAC.

Use of clay-containing waste as pozzolanic additives

Growing productivity of mining and processing enterprises entails an increase in the volumes of liquid tailings impoundments and upstream impoundments of ore processing waste. Enterprises face the challenge of minimizing the environmental impact of waste and guaranteeing the sanitary and epidemiological safety of population. The article presents a possibility of recycling one type of such waste (clay-containing concentration tailings of apatite-nepheline and sylvinite ores, coal beneficiation tailings) by using them after preliminary thermochemical treatment as pozzolanic additives to cements and concretes, including concrete mixtures used for soil stabilization, development of territories, reclamation of mine workings, as a component of the insulating layer of landfills for the disposal of municipal solid waste. An analysis of the phase changes of kaolinite, one of the main minerals that make up clay-containing waste, in the temperature range of 200-1,000 °С showed that a change in its mineral form during heat treatment is the main factor in changing its pozzolanic activity. The effect of heat treatment of clay minerals at temperature of 700-800 °C on their pozzolanic activity, estimated by the ability to absorb calcium hydroxide (0.7 g Ca(OH)2 per 1 g of modified kaolinite), is considered. It is shown that the addition of heat-treated samples (20 % by weight) improves the quality of cement increasing its activity by 15 %, in comparison with the use of unmodified clay minerals. It was proved experimentally that partial replacement of Portland cement with thermally modified kaolinite increases the strength of consolidating stowing mixture by up to 15 %. This approach to processing of ores containing layered silicates, which provides for thermochemical modification of run-of-mine ore, intensifies the processes of tailings thickening and filtering.

Compressed Stabilized Earth Block Incorporating Municipal Solid Waste Incinerator Bottom Ash as a Partial Replacement for Fine Aggregates

This research explores the potential of using municipal solid waste incinerator bottom ash (MSWIBA) as a partial replacement for fine aggregate and ordinary Portland cement (OPC) as a stabilizer in the production of compressed stabilized earth blocks (CSEBs). The study investigates the effect of varying levels of cement content (ranging from 0% to 10%) and MSWIBA content (ranging from 0% to 25%) on the strength and durability of CSEBs. The strength characteristics of CSEBs were evaluated through tests such as wet and dry compressive strength, flexural strength, water absorption, and stress–strain behavior, while durability was tested through wetting–drying cyclic tests. The results indicated that CSEB blocks made with 20% MSWIBA content and 10% cement were able to fulfill strength criteria. Additionally, using these blocks could result in cost savings of 8% during construction when compared to using fired clay bricks (FCB). Furthermore, varying the cement content while maintaining a constant proportion of MSWIBA showed a significant change in the stress–strain behavior and a cost analysis performed for CSEBs stabilized with the optimal quantity of MSWIBA-OPC combination showed that they can be a viable alternative to conventional earth blocks, providing an eco-friendly, sustainable, and cost-effective solution for construction initiatives.

Eco-Friendly Geopolymer Composites Prepared from Agro-Industrial Wastes: A State-of-the-Art Review

Portland cement (PC) is a common material used in civil infrastructure engineering. Cement production emits roughly 2.2 billion tons of CO2 per year, contributing 8% of global emissions in 2016. This contributes to almost half of the calcination process, and together with thermal combustion, clinker generation could be responsible for 90% of the sector’s emissions. One effective technique for dealing with these industrial by-product wastes is to employ them to make cement replacements such as concrete and mortar, which can be used in a variety of applications. As a result, the purpose of this research is to review the current advancements, challenges, and future perspectives on the utilization of agro-industrial waste (AIW) produced around the world in cement-based products. Geopolymers (GPs), on the other hand, reduce carbon dioxide emissions and have the potential to be a complete or partial replacement for PC in the construction sector. The GP technology enables the use of AIW in combination with an alumina–silicate (A–S) phase with minimal environmental impact. GP-cement is mostly produced by activating alkali silicates or alkali sols with secondary raw materials such as calcined clays, fly ash (FA), zeolite, metakaolin, etc. Mixing various resource materials, including additives, A–S, and alkali sols, alkali concentrations, optimizing the curing temperature, the SiO2/Na2O ratio, microstructural behavior, and other factors, results in GP-cement with outstanding mechanical and durability characteristics. The review concludes that AIW-based geopolymer composites have shown promising results in terms of their mechanical properties, durability, and environmental sustainability, which makes them emerge as promising future building materials with applications in a wide range of industries.

Nanomaterial-Reinforced Portland-Cement-Based Materials: A Review.

Portland cement (PC) is a material that is indispensable for satisfying recent urban requirements, which demands infrastructure with adequate mechanical and durable properties. In this context, building construction has employed nanomaterials (e.g., oxide metals, carbon, and industrial/agro-industrial waste) as partial replacements for PC to obtain construction materials with better performance than those manufactured using only PC. Therefore, in this study, the properties of fresh and hardened states of nanomaterial-reinforced PC-based materials are reviewed and analyzed in detail. The partial replacement of PC by nanomaterials increases their mechanical properties at early ages and significantly improves their durability against several adverse agents and conditions. Owing to the advantages of nanomaterials as a partial replacement for PC, studies on the mechanical and durability properties for a long-term period are highly necessary.

Durability Performance of Hybrid Binder Concretes Containing Non-Ferrous Slag and Recycled Aggregates

Novel hybrid binder concrete mixes with alkali-activated non-ferrous slag (NFS), either alone or in combination with blast furnace slag (BFS), as partial replacement of Portland cement, and containing 50% recycled aggregates, were successfully manufactured. The compressive strength, carbonation resistance, chloride resistance, frost scaling, sorptivity coefficient, and water penetration resistance were thoroughly assessed. The presence of recycled aggregates had an adverse effect on early-age strength, but after 91 days there was no difference between concrete with and without recycled aggregates. The chloride-binding capacity was enhanced in the BFS/NFS system with recycled aggregates (reduction in chloride ingress coefficients of ~28–35% compared to recycled concrete with NFS only). This is most likely caused by the binding of Cl ions in calcium alumina silicate hydrates (C-A-S-H) and ettringite phases. However, when compared to the system with virgin aggregates, BFS/NFS concrete with recycled aggregates showed increased carbonation rate (+30%) and frost scaling (+15%). Durability properties, such as sorptivity and water penetration resistance, were positively affected by the curing time for the BFS/NFS system (~35–45% further improvement from 28 to 90 days with respect to the NFS system). Specimens that were wet cured for 91 days showed improved results compared to the 28-day cured samples due to the slow pozzolanic reaction of the NFS.

Effect of Rice Husk Ash on the Mechanical Properties and Microstructure of Concrete Subjected to High Temperatures

Mineral admixtures in portland cement–based concrete, such as rice husk ash (RHA), improve the mechanical strength and durability under normal conditions and ambient temperature. However, more knowledge is needed on the behavior of concretes with these materials when subjected to fire conditions. Fire conditions are characterized by an expressive increase in temperature in the structure in a short period. Thus, this study aimed to evaluate the effect of partial portland cement replacement with RHA in concretes subjected to different temperatures. Parameters examined were mineral composition with X-ray diffraction (XRD), compressive mechanical strength, static modulus of elasticity, and mass loss after heating. The mineral composition of concretes with and without RHA replacement after heating was similar. Partial replacement of cement with RHA improved the mechanical performance with higher compressive strength up to a temperature of 400°C. The static modulus of elasticity degraded more sharply than mechanical strength due to dehydration of cementitious matrix and fissuring. No explosive spalling was observed for all temperatures tested, and the mass loss was similar for both concretes. This indicated no adverse effects in the partial replacement of portland cement with RHA from a mineral point of view.

Durability of Concrete with Partial Replacement of Portland Cement by Incorporating Reactive Magnesium Oxide and Fly Ash

In this research, the durability performance of sustainable concrete with the incorporation of reactive magnesium oxide (MgO) and fly ash (FA) was evaluated. The partial replacement of cement with these two materials is an appealing solution for the construction sector due to sustainability benefits and shrinkage reduction. The incorporation of FA by partial replacement of cement was carried out at 0%, 15% and 30%. The incorporation of MgO in concrete was carried out at 0%, 5%, 10% and 20%. Two types of MgO were used, one from Australia and another of Spanish origin. These two materials were evaluated in terms of their individual incorporation, and then an evaluation was carried out when the two were simultaneously used. In terms of durability, performance losses between 3% and 95% were obtained in all tests (water absorption by capillarity and immersion, carbonation depth and resistance to chloride penetration). However, over time, the difference in performance relative to the reference concrete tends to decrease due to the slow hydration that characterizes these two alternative materials. It was found that, in most of the tests, no overlapping of the negative effects occurred. In other words, the simultaneous incorporation of MgO and FA caused performance losses lower than the sum of the losses of their individual incorporation.