Substituting Portland Cement Research Articles

Assessing the Influence of Brick Powder as Filler in Asphalt Hot Mixes

This study investigated the efficacy of utilizing waste Brick Powder (BP) as a partial or complete replacement for the filler in Hot Asphalt Mixes (HAM). BP was used to substitute Portland Cement (PC) in varying proportions: 25%, 50%, 75%, and 100%. The mixes were evaluated based on Marshall properties, Indirect Tensile Strength (ITS), and Tensile Strength Ratio (TSR). The findings revealed increased Marshall stability, stiffness, and ITS in the mixes containing BP. The flow decreased for HAM containing BP, particularly for those with a complete replacement of cement having utilized BP as the filler, indicating an improved ability of the HAM to withstand loads. The tests conducted at 25, 40, and 60 °C showed that the ITS increased steadily with an increased BP proportion, which is beneficial for rutting resistance, as high service temperatures influence rutting, and high ITS corresponds to a longer rutting life of the asphalt mix. The effect of improving the tensile strength at 60 °C was higher than at 25 °C and 40 °C. Additionally, the BP mixes demonstrated greater resilience to moisture effects compared to the reference mix. The use of BP as an alternative filler for PC did not significantly impact the volumetric properties of the HAM. It was determined that BP could be successfully added to the HAM at a 100% replacement rate as a filler, with an ideal asphalt content of 5.6%. The results suggest that the processing and management of waste bricks can be a sustainable development strategy.

The Production of Rice Husk Ash and Blast Furnace Slag-Based Alkali-Activated Composites under High-Temperature Effects

Alkali-activated concretes offer several advantages over conventional Portland cement-based concretes, including environmental sustainability, cost-effectiveness, and improved permeability. The use of alkali-activated concretes, as a replacement for Portland cement, provides significant environmental benefits, such as reducing carbon dioxide emissions by up to 80%, and facilitates the recycling and reuse of industrial and agricultural by-products. This study focuses on the development of alkali-activated concrete by incorporating industrial by-products like blast furnace slag and rice husk ash. A mixture of alkali-activated concrete based on blast furnace slag will be prepared, with partial substitution of Portland cement by these by-products by weight. The study will investigate the effects of these substitutions on the flexural and compressive strengths of the concrete over periods of 7, 28, and 90 days, as well as its fire resistance at temperatures of 200, 400, 600, and 800°C. The aim of this research is to contribute to the advancement of alkali-activated concrete technology, promoting the use of industrial by-products in the creation of more sustainable and environmentally-friendly construction materials.

An assessment of the pozzolanic potential and mechanical properties of Nigerian calcined clays for sustainable ternary cement blends

This study investigates the potential of calcined clays from Nigerian deposits as supplementary cementitious materials. Clay materials were obtained from three sites namely: Ikpeshi, Okpilla and Uzebba. The raw clay samples were then calcined at 700°C and 800°C. Chemical and mineralogical compositions were determined for the raw and calcined clay samples using XRF and XRD respectively. The chemical composition by XRF confirmed these clays as potential pozzolans with SiO2, Al2O3, and Fe2O3 collectively exceeding 70%. XRD analysis identified kaolinite and quartz as major mineral phases in the raw clays, which transformed into metakaolin upon calcination. Thermo Gravimetric Analysis (TGA) indicated varying lime consumption levels among the clays, with Ikpeshi clay displaying the highest pozzolanic reactivity and Uzebba clay the least. Compressive strength investigation on mortar cubes prepared with 50% substitution of Portland cement with the calcined clay and limestone, showed that Ikpeshi clay at 800°C had the best strength performance, with strength activity index of 0.92 (at age 28 days), demonstrating superior pozzolanic potential. Strength development was more significant between 7 and 28 days, indicating the pozzolanic reaction's contribution to long-term strength. However, initial strength at 3 days was lower than the reference Portland cement due to a delayed pozzolanic reaction. XRD analysis of blended pastes revealed typical phases of hydration like portlandite, calcium silicate hydrate phase, strätlingite, and ettringite, with the calcined clay blends showing reduced portlandite content, indicating absorption by the pozzolan's alumina phase.

Compressive strength and regional supply implications of rice straw and rice hull ashes used as supplementary cementitious materials

Substituting Portland cement (PC) with supplementary cementitious materials (SCMs) is a key strategy for reducing greenhouse gas (GHG) emissions. Considering alternative SCMs requires a holistic understanding of changes to material performance, emissions reduction potential, and regional availability. Four rice hull ashes (RHAs) and one rice straw ash (RSA) were evaluated to replace PC in mortars (10% untreated ash and 30% blast furnace slag; 15% untreated ash; or 15% milled ash). The 28-day compressive strengths with 0.59 water-to-binder ratio for fly-RHAs (38.0–49.8 MPa) and RSA (37.7 - 44.1 MPa) did not vary significantly from the PC control (43.2 MPa) based on an ANOVA. Modeling rice biomass generation in six U.S. states shows RSA could triple the supply of rice-biomass ash, but in states with substantial PC demand, i.e., California and Texas, the potential GHG reduction may remain small (∼1–2%). RSA and RHA may hold promise in lowering concrete GHG emissions.

Application of novel deep neural network on prediction of compressive strength of fly ash based concrete

ABSTRACT Fly ash (FA)-based high-strength concrete (HSC) has attracted significant interest due to its potential to substitute Portland cement, offering both environmental benefits and improved performance. However, the design of FA-HSC is challenging, as key factors such as fly ash percentage, water content, and superplasticizer dosage have a complex influence on compressive strength. This study aims to develop an efficient predictive tool for FA-HSC mix design, using artificial intelligence (AI) models to address the inherent variability and uncertainty in these parameters. Six AI models, including a Deep Neural Network (DNN), were employed to analyse the relationships between mix design variables and compressive strength. The DNN model, in particular, demonstrated superior performance compared to the other models, with a high coefficient of determination (R2 = 0.89), variance accounted for (VAF = 88.3%), root mean square error (RMSE = 0.06), and residual standard error (RSR = 0.31). These results indicate that the DNN model can provide reliable predictions of compressive strength, offering a more efficient alternative to traditional trial-and-error methods. The AI-based approach can save both time and material costs while optimising performance. Overall, this AI-driven model contributes to the advancement of sustainable concrete technology by enabling more precise and resource-efficient mix designs for FA-based high-strength concrete.

Effect of Epoxy Resin on the Strength Propery of Portland Cement Concrete

In this study, the strength effect of partially substituting Portland Cement (PC) with epoxy-resin in making concrete was examined. A mix ratio of 1:1.87:2.67 (PC: sand: granite chippings) at water-cement ratio of 0.5 targeting a strength of 30N/mm2 was adopted. The epoxy resin was mixed with hardener at a proportion of 1:0.5 and this mixture was used to replace PC at 10% intervals starting from 0% to 40%. Six cubes were cast for each mix ratio and were cured in water at room temperature for 28 days. The first set of samples were treated by heating them in an oven to a temperature of 1000C for 1 hour before testing in compression while, the other set were not treated. Results showed that as the quantity of epoxy resin in the concrete enlarged the compressive strength values reduced. But a rise was observed at 30%. All concrete produced were structural in nature except for the heated 40% specimen. An optimal replacement strength of 32.10 N/mm2 at 30% inclusion (unheated) and lowest strength of 18.63 N/mm2 at 40% replacement (heated) were obtained. The heated samples experienced further reduction in their compressive strength values. An 8.94% drop in strength was observed between the maximum replacement values for the heated and unheated samples at 30%. In conclusion, epoxy resin concrete can be used for structural works at replacement levels up to 40%. However, if the concrete will be exposed to increased temperature of 1000C, then an optimal replacement level of 30% is recommended.

Machine Learning to Predict Workability and Compressive Strength of Low- and High-Calcium Fly Ash–Based Geopolymers

The potential substitution of Portland cement–based concrete with low- and high-calcium fly ash–based geopolymers was investigated. However, predicting the workability and compressive strength of geopolymers with the desired physical and mechanical properties is a complicated process because of the variety of chemical compositions found in aluminosilicate sources. Therefore, machine-learning techniques were used to predict the physical and mechanical properties of the geopolymers and eliminate the usual trial-and-error laboratory procedures. The experimental and predicted results of geopolymer properties using the multilayer perceptron regressor, voting regressor, and XGBoost techniques were compared. The XGBoost model outperformed the other models in terms of accuracy for predicting workability and compressive strength, producing the R2 of 0.96 and 0.89, respectively. Sensitivity analysis determined that the percentage of CaO had the largest effect on geopolymer workability of 27.13%. Fly ash content had the largest effect on compressive strength of 34.44%. Our approach offers a straightforward and dependable strategy for designing and optimizing fly ash–based geopolymers.

Reducing Energy Demand in Concrete Pavements by the Use of Blended Cements

This research explores strategies to minimise energy consumption and enhance environmental sustainability in road construction. Focusing on concrete pavement structures, the study evaluates the impact of substituting Portland cement with environmentally friendly alternatives such as fly ash and blast furnace slag. A comprehensive model is employed to analyse the energy demands of different pavement types, considering various cement replacements over their lifetime, from the initial extraction of materials to the conclusion of construction. Results indicate an energy saving potential of 8.63% by substituting 10% of Portland cement with fly ash, while an impressive reduction of 58.63% in cement production energy is achieved by replacing Portland cement with 80% blast furnace slag. The study underscores the significant role of cement variations in mitigating energy consumption, emphasizes the potential of blast furnace slag as a sustainable alternative as well as highlights the significance of alternative cement types in reducing energy consumption in concrete pavement construction, aligning with environmental sustainability goals and offering insights for more eco-friendly infrastructure development.

Manufacturing and performance of eco-efficient cementitious blocks for thermal cycling in thermal energy storage

Solar energy is a promising renewable option to provide energy demands in combination with conventional energy sources. However, to enhance the integration of renewable energies into the industrial section, it is necessary to employ thermal energy storage media. Among different thermal energy storage options, concrete has proven to be a very effective sensible thermal energy storage solution. However, its main raw material (i.e., the Portland cement), is the cause of huge CO2 emissions to the environment. This study focuses on the design, manufacture, assembly and experimentation of thermal energy storage blocks made of alternative binders in substitution of Portland cement: i.e., hybrid materials and alkaline activated materials. The thermal energy storage blocks have been thermally cycled, with a charging temperature of 228 °C and a discharging temperature of 30 °C, in order to analyze the operational times and temperatures. The results obtained are very promising and comparable to those of the Portland cement system. Charging times have improved, with the alternative materials achieving temperature increases of up to 4%, while greater stabilization has been achieved during discharge, with the fluid reaching temperatures up to 6% higher than the reference system. These advancements support efficient, sustainable thermal energy storage technologies.

Compressive Strength Analysis of Renewable Mortar after Portland Cement Replacement with Waste Ash

There are many environmental problems caused by factory waste. Sugar factory waste, in the form of bagasse ash, and PLTU factory waste, in the form of fly ash, are currently in the spotlight of science studies. This study used waste bagasse and fly ash to substitute Portland cement as the main ingredients for mortar. Baggash and fly ash waste were collected, processed, and then used to replace cement by up to 40% to determine to what extent they could be used in brick masonry work, wall plastering, and masonry paste. Experimental tests were carried out on mortar cube samples measuring 5×5×5 cm, comparing four types of samples consisting of Portland cement, bagasse ash, and fly ash. The compressive strength results were obtained after 28 days. Normal Mortar (MN=11.75 MPa) had higher compressive strength than the substitute mortar types MA (3.23 MPa), MB (3.09 MPa), and MC (2.98) MPa. According to SNI 6882-2014, MA, MB, and MC mortars can be used as O-type mortar (2.4 MPa). Therefore, they can be applied to wall plastering or walls not bearing loads.

Properties and microstructure of soil solidified by titanium slag-flue gas desulfurized gypsum-Portland cement composites as solidifiers

Using Portland cement for soil solidification has sustainability issues due to high energy-consumption and carbon emissions. An innovative approach suggests using titanium slag and flue gas desulfurized gypsum as substitutes for Portland cement for soil solidification. This study systematically evaluates the effects of titanium slag-flue gas desulfurized gypsum-Portland cement composite (TS-FGD-OPC composite) solidifier on the performance of solidified soils. The evaluation includes assessing the unconfined compressive strength (UCS), elastic modulus, moisture content, and leachate pH value. Additionally, the hydration process and microstructure development of the solidified soils are characterized through the XRD, TG-DSC, BET, and SEM tests. The results indicate that the although its compressive strength is much lower, TS-FGD-OPC composite can be used as soil solidifier. With the titanium slag content increase, the TS-FGD-OPC composite solidifier brings the solidified soils to have lower UCS, elastic modulus and leachate pH value, and higher plastic deformation and moisture content. However, to get the same UCS, the utilization of the TS-FGD-OPC composite solidifier can bring the significant reduction of the Portland cement consumption. At the same dosage, the TS-FGD-OPC composite incorporating 50 % titanium slag and 20 % flue gas desulfurized gypsum yields an UCS achieving up to 92.5 % of that in pure Portland cement solidified soil. This is attributed to the filling of pores between soil particles with hydration products and unhydrated particles, resulting in the densification of the solidified soils and the cohesion increase of soil particles. The findings confirm the feasibility of substituting Portland cement with titanium slag and flue gas desulfurized gypsum to prepare an effective and environmentally friendly soil solidifier, to reduce the demand for Portland cement in soil solidification.

A green binder for cold weather applications: enhancing mechanical performance of alkali-activated slag through modulus, alkali dosage, and Portland cement substitution

Below 5 °C, Portland cement (PC) experiences delayed hydration, slowing strength development, making it unsuitable for winter. Alkali-activated slag (AAS) emerges as a viable alternative with continuous hydration in low-temperature conditions. The effect of the activator nature on the performance of AAS cured at normal temperatures is well known, but further studies are required for low-temperature conditions. This study investigates the synergistic impact of activator modulus (1.2 and 1.5), alkali dosage (5, 7, and 9%), and PC substitution rates (0, 10, and 20%), on low-temperature cured AAS properties. Eighteen mixtures were prepared and cured at 2 °C. Compression and ultrasonic pulse velocity tests were conducted after 7, 28, and 90 days. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy analyses were performed to examine the microstructure of the samples. Elevating alkali dosage enhanced early age strength but resulted in a drop in 90-day strength. Simultaneous increases in modulus and PC substitution rate reduced strength due to shrinkage-induced crack formation. Optimal mixture design options included using 10% PC in the 1.2 modulus and omitting PC when the 1.5 modulus was selected. Despite low temperatures, the use of PC significantly accelerated the setting time. Altering modulus and alkali dosage caused a considerable change in the intensity of the peaks in the FTIR spectrum. The findings indicate that AAS shows promise when adjusting the mixture design for temperatures below 5 °C, which are unfavorable for the hydration of PC.

The Optimum Percentage of Rice Husk Ash (RHA) as Partial Cement Replacement in Engineered Cementitious Composite (ECC)

Rice Husk Ash (RHA) is a potential supplementary cementitious material (SCM) in concrete production due to their capability of pozzolanic reaction. This research study on the fineness, workability and compressive strength of the RHA incorporated into Engineered Cementitious Composites (ECC) as a cement replacement alternative hence to determine the optimum percentage of RHA to be use in the ECC mix. The mix proportional of RHA-ECC was designed with RHA as the substitution of Portland cement at various percentages by volume, including 5%, 10%, 15% and 20% respectively. Physical characterization of RHA was determined by particle size distribution test. The workability of hand mixed mortar was determined by the flow table test. A total of 45 cubes of 50×50×50 mm was prepared and cured for 7, 14 and 28 days. These hardened mortars were test with the compressive strength test to study its mechanical property. Findings showed that the workability of RHA-ECC was decreased with increasing of the amount of RHA added. The compressive strength of RHA-ECC was best at 28 days with the 10% of replacement level compared to others. This study will provide both direction and knowledge on the application of RHA as a greener and sustainable cement replacement.

Influence of Sunflower Seed Husks Ash on the Structure Formation and Properties of Cement Concrete

The limitation of the application of non-renewable materials is one of the solutions to the problem of the sustainable evolution of civilization in the 21st century. Using additional binders in concrete obtained from plant waste will be economically and environmentally beneficial and will also allow us to move closer to achieving sustainable development goals. This study searches for rational composition components and a methodological approach regarding the technological characteristics to get the highest quality elements and prime concrete properties on the basis of sunflower seed husk ash (SSHA). Experimental concrete specimens were manufactured with partial Portland cement substitution with SSHA amounts ranging from 2% to 16% by weight in increments of 2%. This study focuses on investigating the density and workability of the concrete mixture, along with the compressive strength, concrete density, and water absorption. This article used granulometric, microscopic, and X-ray phase analysis methods. Including SSHA in all considered ranges reduces the slump in concrete mixtures. The optimal SSHA content in concrete is up to 12%. An 8% SSHA content has been found to deliver the most favorable mechanical characteristics of the concrete studied. The compressive strength of the investigated concrete has increased by 14.89%, and water absorption has decreased by 15.78%. Doi: 10.28991/CEJ-2024-010-05-08 Full Text: PDF

COMPRESSIVE STRENGTH, FLOWABILITY, AND ULTRASONIC PULSE VELOCITY TESTS OF PORTLAND CEMENT-FLY ASH-CALCINED CLAY MORTARS

The cement production process significantly affects the environment and contributes to air pollution. Consequently, there is a growing emphasis on employing alternative materials or minimizing cement usage as a solution to address environmental issues and reduce air pollution. In this investigation, an examination was conducted by substituting Portland cement with a weight of 50% with both fly ash and calcined clay. The findings revealed that replacing Portland cement with fly ash resulted in a decrease in compression strength. However, concurrently incorporating calcined clay increased compressive strength. Higher compressive strength compared to the 50% Fly ash mix was achieved by adding 20 wt.% Metakaolin and 20 wt.% Calcined clay Lopburi due to their finer particle size. As a result, the pozzolanic reaction is better than Lampang calcine clay (30FA20CClam). Additionally, ultrasonic pulse velocity testing indicated that higher values in the specimen correlated with increased compressive strength.

Efficient machine learning models for estimation of compressive strengths of zeolite and diatomite substituting concrete in sodium chloride solution

This study implements a set of machine learning algorithms to building material science, which predict the compressive strength of zeolite and diatomite substituting concrete mixes in sodium chloride solution. Particularly, Random Forest, Support Vector Machine, Extreme Gradient Boosting, Light Gradient Boosting, and Categorical Boosting algorithms are exploited and their optimal parameters are tuned. In the training and testing of these models, 28 day, 56 day, and 90 day compressive strength observations of 63 samples of 7 different concrete mixtures substituting Portland cement, zeolite, diatomite, zeolite + diatomite were used. Consequently, compressive strength experimentation results and machine learning predictions were compared through statistical methods such as RMSE, MAPE, and R2. Results denote that the prediction performance of machine learning is improving with tuned models. Particularly, RMSE, MAPE, R2 scores of Categorical Boosting are, respectively, 1.15, 1.45%, and 98.03% after parameter tuning design. The results denote that presented machine learning model can provide an advantage in the cost and duration of the compressive strength experiments.

Strength, carbon emissions, and sorptivity behavior of cement paste and mortar containing thermally activated clay

The detrimental impact of anthropogenic gases such as carbon dioxide, methane, and nitrous oxide has become a pressing concern across various industries. In this study, thermally activated clay (TAC) was investigated as a substitute for Portland cement in proportions ranging from 10 to 40 wt%. Compressive strength and efficiency factors were employed to ascertain the optimal mortar mixture. Both the control mortar and the optimal blend underwent capillary water sorptivity tests. Fourier Transformed Infrared spectroscopy (FT-IR) was utilized to gain insight into the hydration process and pozzolanic reaction within the mortar mixtures. Furthermore, the study assessed the impact of the optimized blended mortar on greenhouse gas emissions through estimated carbon dioxide equivalent values. Results revealed that incorporating 30% TAC attained the maximum strength of approximately 33, 36, and 48 MPa at 3, 7, and 28 days respectively compared with the other mortars. The mortar containing 30% TAC enhances both compressive strength and efficiency factors, demonstrating effective pozzolanic activity and minimal compromise on performance. Notably, the inclusion of 30% TAC also led to reduced water absorption rates, indicating improved durability-related performance. Additionally, the study uncovered the superior performance of the 30% TAC mix in terms of efficiency factors and carbon savings. FTIR analysis provided novel insights into the hydration and pozzolanic reactions induced by TAC, resulting in the formation of compounds contributing to enhanced compressive strength over time. This research advocates for the substitution of Portland cement with TAC as a low-carbon binder alternative to traditional Portland cement binders.

Macroscopic behavior and microscopic structure of serpentine-MgO carbon sequestration foamed concrete

This paper proposes a novel approach for preparing foamed concrete that involves the substitution of Portland cement with serpentine wastes and magnesium oxide (MgO), along with the utilization of carbon dioxide (CO2) foam instead of air foam. The existence of CO2 foam promotes the dissolution and carbonation of MgO and serpentine. Six distinct sample groups with varying serpentine proportions ranging from 0% to 50% were meticulously prepared. The incorporation of serpentine enhanced the sample fluidity and prolonged the sample setting time. The results demonstrated that the serpentine-MgO samples achieved the highest unconfined compressive strength (1.4 MPa) at a serpentine proportion of 30%, and excessive serpentine content negatively influenced the mechanical performance and microstructure development. The improvements in carbonates content, morphologies and microstructure in samples containing 30% serpentine proved the low-carbon potential of the proposed approach. Overall, serpentine-MgO carbon sequestration foamed concrete (SC-FC) could emerge as a promising sustainable construction material for CO2 sequestration.

Exploring the Utilization of Activated Volcanic Ash as a Substitute for Portland Cement in Mortar Formulation: A Thorough Experimental Investigation.

The manufacture of natural pozzolans as cement products is economically affordable and contributes to CO2 mitigation in the cement-based materials industry. Through two experimental stages, this study evaluates the feasibility of using volcanic ash (VA) to partially substitute portland cement (PC) in mortar production. In Stage 1, the effectiveness of different activation methods, such as calcination, alkali activation, and lime addition, in enhancing VA reactivity was assessed when the mortars were produced using 35% VA. The compressive strength (fcm) and physical properties of the mortars produced were determined at 7 and 28 days and compared with those of mortars without activated VA. In Stage 2, the most effective treatments obtained from Stage 1 were applied to produce mortars with 50% and 75% of VA replacements, focusing on their physical and mechanical properties. The findings revealed promising results, particularly when mortars were produced with up to 50% calcined VA (CVA) at 700 °C and 20 wt% lime addition, reaching a higher fcm than 45 MPa. Chemical activation with 2% CaCl or 1% NSi enhanced early-age strength in 35% VA-based mortars. Additionally, NSi-activated CVA-lime-based mortar at 50% VA achieved a notable fcm of 40 MPa at 28 days. Even mortars with 75% VA replacement achieved an adequate compressive strength of 33MPa at 28 days. This study determined that VA-based mortars have the potential for construction applications.

Calcined schist as promising ordinary Portland cement substitution: C3

AbstractAn effective method to make cement and concrete more sustainable is to blend them with the proper supplementary cementitious materials (SCMs). This study evaluates a pair of schist‐type materials with slightly different phase compositions, as a partial replacement for ordinary Portland cement (OPC). Materials received from several mines in ground powder form were studied by X‐ray diffraction, thermogravimetric analysis (TGA), and scanning electron microscopy. According to the TGA results, the activation procedures for the candidate SCMs were determined. The as‐received powders were heat treated in three different decomposition regimes (30%, 50%, and 80% of the total weight losses during thermal decomposition). These regimes corresponded to the activation level of the potential SCMs due to the de‐hydroxylation of the clay‐type minerals within them. Pozzolanic reactivity (pozzolanicity) of untreated as well as treated powders were estimated via electrical conductivity measurements in saturated calcium hydroxide solution. Blended cement pastes with 30 wt.% of OPC substituted with calcined clay‐type materials have developed mechanical properties equal to those of pure cement (100 wt.% OPC) paste after 28 days of hydration time. Two blended cement pastes prepared with candidate SCMs were compared to 100% OPC and OPC composite paste with metakaolin, which is regarded in the literature as a standard.