Cementitious Materials Research Articles

A novel approach to modified polyethylene fibres with size effect in cement mortar

A novel method for modifying polyethylene fibres (PE) that is simple, efficient, time-saving and cost-effective is proposed in this article. Analytical techniques, including Raman spectroscopy, Fourier infrared spectroscopy and microscopic characterization, are employed to demonstrate that this new method effectively attaches graphene oxide (GO) to the surface of PE fibers. Furthermore, analyses using nanoindentation tests and scanning electron microscopy reveal that the GO on the surface of the modified fibers densifies the hydration structure in the transition zone at the interface between the fibers and the cement matrix. This densification enhances the efficiency of stress transfer from the matrix to the fibers, thereby improving the mechanical strength of the cementitious materials and significantly reducing their size effect.

Assessing the Usage of Barytes Powder and Cuddapah Stone Dust as Supplementary Cementitious Materials in Concrete of Grade M30 and M35

This research studied the effects of using Barytes powder and Cuddapah stone waste as substitutes for cement in M30 and M35 grade concrete using OPC. Cement production is known to harm the environment and consume a lot of energy, making the search for alternative materials to replace cement in concrete important.In this study, different amounts of Barytes powder and Cuddapah stone waste were added to concrete mixes as partial replacements for cement. The resulting concrete was tested for compressive strength and compared to normal concrete. The experiment involved making concrete samples with varying percentages of cement replacement, ranging from 0% to 50%, using Barytes powder, Cuddapah stone waste and Combination. The samples underwent standard curing and testing according to Indian standards.The research analysed the results to find the optimum percentage of cement replacement that provided satisfactory mechanical properties. This study determined the feasibility and effectiveness of using Barytes powder and Cuddapah stone waste as partial replacements for cement in concrete production.

Feasibility study of novel Bengal Gram Husk Ash as a supplementary cementitious material: mechanical, durabilty and microstructural assessments

Feasibility study of novel Bengal Gram Husk Ash as a supplementary cementitious material: mechanical, durabilty and microstructural assessments

Development and performance evaluation of ultra-lightweight geopolymer foam insulation material

The preparation technology for new ultra-lightweight geopolymer insulation materials (ULGIM) has been developed based on the principle of alkaline activation, and ULGIM for building walls have been obtained. It has improved the problem of traditional inorganic foam insulation material that cannot balance density, insulation performance, mechanical performance and environmental performance. The composition of supplementary cementitious materials, the mass ratio between each component, and water to binder ratio (w/b) were used to analyze the thermal conductivity, dry density, volumetric water absorption, compressive strength, average pore diameter, and porosity of ULGIM. The life cycle assessment (LCA) method was employed to assess the environmental impact of ULGIM production. The test results showed that ULGIM achieved a dry density and thermal conductivity of ULGIM only 181.17 kg/m3 and 0.0427 W/(m·K), respectively, and the optimal compressive strength was 0.72 MPa at 7 d. ULGIM exhibited superior compressive strength, lower thermal conductivity, and smaller environmental impact in comparison to cement-based foamed materials with comparable dry density.

Acoustic emission analysis of self-healing properties in cementitious materials with superabsorbent polymers (SAPs) during different environments

This paper studies the coupling effect of superabsorbent polymers (SAPs) and fly ash on the self-healing performance of mortar. The three-point bending test was used to evaluate the mechanical property recovery effect of mortar specimens after curing in different environments, and the relationship between crack closure rate, flexural strength and flexural stiffness recovery was established. The amplitude and energy in acoustic emission were used to evaluate the characteristics of self-healing products. The results show that compared with the control specimens, the addition of SAP improves the crack closure rate and mechanical property recovery effect of mortar specimens. With the increase of SAP particle size and content, the mechanical property recovery rate and crack closure rate increase accordingly. The order of self-healing effect of specimens in different healing environments is saturated calcium hydroxide > water >97 % RH > air. After reloading, the amplitude number and cumulative energy of samples with SAP are larger than those of the control specimens. The SEM results also prove this, and the self-healing products in the crack area of the mortar specimens with SAP are denser than those in the control specimens.

Enhancing mechanical properties and crack resistance of high-strength SHCC/ECC for durable transportation through ethylene-vinyl acetate polymer modification

Strain-hardening cementitious composites (SHCC) possess excellent ductility and toughness, making them suitable for reinforcement and repair projects of transit infrastructures, such as tunnel linings, bridges, and highways. Especially, polyethylene (PE) fiber is admixed to SHCC for fabricating high-strength PE-SHCC. However, the hydrophobic nature of PE fibers results in relatively weak interfacial frictional bond strength with cementitious matrix, ultimately leading to larger crack widths and wider gaps. This poses durability and safety concerns for the practical applications of PE-SHCC in transit infrastructure. In this study, ethylene-vinyl acetate (EVA) dispersible polymer is selected to address this problem. The effect of admixing EVA on mechanical and direct tensile properties of PE-SHCC is investigated. The compressive strength, first crack strength and matrix fracture toughness of PE-SHCC tended to decrease after EVA modification, however, the tensile strength and tensile strain increased significantly with doping. After that, the single fiber pullout test combined with flaw size/distribution analysis is performed to explore the improvement mechanism of PE-SHCC after EVA modification. It was found that the addition of EVA could significantly improve the interfacial transition zone (ITZ), increase the interfacial friction between PE fibers and matrix, and optimise the defect distribution within the matrix. The recommended dosage of EVA is 3–6 % comprehensive consideration of the tensile strength, strain energy, crack width, and mechanical strengths of the EVA-modified PE-SHCC. The enhancement of mechanical strengths and crack resistance in PE-SHCC contributes to the development of transit infrastructure towards greater reliability, durability, and resilience.

Organic and Inorganic Modifications to Increase the Efficiency in Immobilization of Heavy Metal (Zn) in Cementitious Composites-The Impact of Cement Matrix Pore Network Characteristics.

This research investigated the properties of modified cementitious composites including water purification from heavy metal-zinc. A new method for characterizing the immobilization properties of tested modifiers was established. Several additions had their properties investigated: biochar (BC), active carbon (AC), nanoparticulate silica (NS), copper slag (CS), iron slag (EAFIS), crushed hazelnut shells (CHS), and lightweight sintered fly ash aggregate (LSFAA). The impact of modifiers on the mechanical and rheological properties of cementitious composites was also studied. It was found that considered additions had a significantly different influence over the investigated properties. The addition of crushed hazelnut shells, although determined as an effective immobilization modifier, significantly deteriorated the mechanical performance of the composite as well as its rheological properties. Modification by iron slag allowed for a significant increase in immobilization properties (five-fold compared to the reference series) without a substantial impact on other properties. The negative effect on immobilization efficiency was observed for nanoparticulate silica modification due to its sealing effect on the pore network of the cement matrix. The capillary pore content in the cement matrix was identified as a parameter significantly influencing the immobilization potential of most considered modifications, except biochar and active carbon.

Utilizing diatomaceous earth (DE) as a sustainable substitute in alkali-activated cementitious materials: Performance and life cycle assessment

As the demand for alkali-activated cementitious materials (AACM) increases, reliance on blast furnace slag (BFS) raises concerns about potential shortages. This study evaluates the substitution of BFS with diatomaceous earth (DE) in AACM, using three DE types—raw (RDE), calcined (CDE), and spent (SDE)—at substitution rates of 0–30 %. The impact of these substitutions on fluidity, setting time, and compressive/flexural strength of the prepared mortar was assessed, along with an analysis of the mechanisms through hydration heat, product composition, and pore structure. Results indicate that DE, characterized by the porous structure and high content of amorphous silica, enhances early hydration, reduces fluidity, accelerates setting times, and refines pore structure, thereby improving strength. CDE, with its low organic content and large surface area, exhibited the best performance, while SDE was effective despite impurities, and RDE performed the poorest. Increasing DE substitution raised water absorption, impacting fluidity and setting times, with 20 % identified as the optimal substitution rate, balancing strength and workability. The entropy method-analytic hierarchy process (EM-AHP) confirmed this rate, with CDE as the optimal variant. Life cycle assessment (LCA) showed that while SDE reduces environmental impacts significantly, CDE achieves a greater reduction when considering both environmental and mechanical performance. In conclusion, CDE and SDE are viable BFS substitutes in AACM, offering enhanced performance and reduced environmental impacts.

An innovative sludge-derived capsule for self-healing cementitious materials

An innovative eco-efficient capsule utilizing drinking water treatment sludge (DWTS) as a healing agent for concrete crack sealing was developed. In this study, the core materials comprised a mix of DWTS and calcium hydroxide, granulated by poly (ethylene glycol). A non-toxic polymer, Ethyl cellulose (EC), is applied as the protective shell material. The morphology, internal structure, and leakage mechanism of capsules, self-healing performance of cracked mortars and the composition of resulting healing products were assessed. Obtained results indicated that EC uniformly covered the spherical core material following the designed coating procedures. The main elements released from the capsules were Ca, Al and Si after dissolution of polyethylene glycol (PEG), which would contribute to pozzolanic reactions inside the matrix. Cracks with an initial width of 400 μm were completely healed after 7 days of curing. Such a healing process also led to an 73% enhancement in compressive strength at a healing age of 28 days. The water tightness of capsule-based samples improved by more than 90% in the first 7 days, compared to only 10% in control samples. The predominant healing products were calcium carbonate in the form of calcite, and some content of aluminium-bearing phases derived from the pozzolanic reaction of DWTS.

A conceptual model for sustainable cementing operations in offshore wells

This review paper introduces a conceptual model to enhance the sustainability of cementing operations in offshore wells. Traditional cementing practices, characterized by significant greenhouse gas emissions and compliance challenges, necessitate the development of more environmentally friendly approaches. The proposed model integrates low-carbon cement alternatives, such as geopolymer cements and supplementary cementitious materials (SCMs), with advanced slurry designs that incorporate nanomaterials, biodegradable additives, and recycled materials. This integrated approach reduces the environmental impact and enhances the mechanical properties and durability of cementing operations. The paper provides operational guidelines for implementing this model and discusses future prospects, emphasizing the importance of continued research and collaboration among industry stakeholders. By adopting these innovative practices, the oil and gas industry can achieve significant environmental benefits and ensure compliance with stringent regulatory standards, paving the way for a more sustainable future in offshore drilling.

Mitigating autogenic shrinkage in high‐performance concrete using wollastonite: A structural enhancement approach

AbstractThis study investigates the influence of wollastonite fiber as a reinforcement in high‐performance concrete (HPC), focusing on its potential to mitigate autogenic shrinkage and enhance overall structural properties. HPC known for its superior strength and low permeability, often suffers from intensified autogenic shrinkage, leading to micro‐cracking and compromising durability. To address this challenge, wollastonite was incorporated at different substitutions (0%, 5%, 10%, and 15%) for both cement and aggregate. The experimental program involved a systematic evaluation of compressive strength, flexural strength, porosity, water absorption, and corrosion resistance with tests conducted at different curing periods. We found that the addition of 10% wollastonite significantly enhances compressive strength (up to 20% after 90 days) and flexural strength (maximum improvement of 21%). The water permeability was decreased by 29% and improved resistance to steel reinforcement corrosion, demonstrating enhanced durability compared to conventional HPC. However, diminishing returns were observed at higher wollastonite replacement levels (15%), indicating a threshold beyond which mechanical and durability benefits were reduced due to potential issues with fiber dispersion and workability. Our findings suggest that wollastonite is a promising, cost‐effective additive for improving HPC. The study contributes new understandings into optimizing HPC mixtures for greater durability and sustainability, while also reducing the environmental footprint through partial cement replacement. Future research is needed to explore the long‐term performance of wollastonite‐reinforced HPC under different environmental conditions and its combination with other supplementary cementitious materials for further enhancement.

Performance evaluation of untreated sugarcane bagasse ash as partial replacement of cement on setting time and compressive strength of M15 concrete

Due to its escalating cost, cement, the primary component of concrete, has become a significant issue in Nigeria over time. The use of agricultural wastes such as cow bones, periwinkle shells, rice husks,and sugarcane bagasse as additives to partially replace cement has been made possible by scientific efforts to find alternative and effective materials from large deposits of agricultural wastes. This study examines how adding sugarcane bagasse ash (SCBA) to concrete affects its strength properties. Sugarcane bagasse ash was successfully included in various amounts (0, 2.5, 5.0, 7.5, and 10% by weight of cement). A mix design of 1:2:4 (M15) grade and a water-cement ratio of 0.5 was used to cast 60 concrete cubes measuring (150 x 150 x 150) mm. Concrete's workability and setting time were improved by adding sugarcane bagasse ash to the cement. The outcome revealed a reduction in concrete density with an increase in percentage replacement of sugarcane bagasse ash. Addition of sugarcane bagasse ash to cement increased the concrete's workability and speed of setting. The results showed that concrete density decreased as sugarcane bagasse ash replacement percentage increased. This is not unrelated to the fineness of sugarcane bagasse ash, which makes the cementitious matrix and aggregate interface more intense and lighter. Concrete's compressive strength was discovered to be decreased by the usage of sugarcane bagasse ash. Between 0, 2.5, 7.5, and 10% sugarcane bagasse ash, the average compressive strength measured at 28 days was found to be 25.93, 25.19, 23.70, 20.30, and 18.96 MPa, respectively. 10% sugarcane bagasse ash concentration was suggested as the optimal level to employ for improving concrete characteristics.

Experimentally Verified Retrofit Combining Hybrid Solutions for Enhancing the Seismic Response of Multistory RC Structures

ABSTRACTThis experimental and numerical study proposes hybrid retrofit alternatives involving multiple contemporary techniques to upgrade the fundamental seismic response characteristics of multistory reinforced concrete frame (MSRCF) structures. The impact of thin high‐performance reinforced concrete (HPRC) jackets on the concrete framing system's seismic response is first investigated through shake table testing (STT). The performance of the HPRC‐retrofitted frame is then compared with another STT campaign conducted for fabric‐reinforced cementitious matrix (FRCM)–retrofitted frame. The STT results indicated that at the same input ground motion intensity that caused failure for the FRCM‐retrofitted frame, the curvature ductility and interstory drift ratio of the HPRC‐retrofitted specimen were reduced by 79% and 87%, respectively. Upon verifying the fiber‐based modeling technique of HPRC and FRCM alternatives through STT, the study probabilistically assesses the seismic performance of a benchmark MSRCF building considering different hybrid retrofit alternatives by combining each technique with a self‐centering energy dissipation (SCED) bracing system. Following a systematic seismic assessment framework, it is concluded that the performance‐cost index of the less disruptive HPRC‐SCED option exceeded that of the FRCM‐SCED by 36%, confirming its preference among the considered alternatives for upgrading the seismic response of MSRCF deficient in stiffness, strength, and ductility.

Analysis of the Physical and Chemical Composition of Sludge from the Water Treatment Plant

The properties and composition of the sludge generated in water treatment systems depend primarily on the type and composition of the water to be treated, the treatment methods, and the type and doses of chemical reactants. The sludge produced in the water treatment plant (WTP) under study follows the technological processes of coagulation, flocculation, sedimentation, and filtration. The analyses aimed to characterize the sludge in terms of its physico-chemical properties and classify it in terms of its potential discharge into the river and management. Four series of sediment tests were conducted over a calendar year (March, June, September and December), analysing selected parameters using various test methods, including the X-ray crystallography (XRF) method. The publication's authors showed that the sediment consists mainly of sand, clay, and silt particles with grain sizes ranging from 0.001 mm to 1 mm. Silica (53.78%), alumina (23.58%), calcium oxide (8.28%), iron (III) oxide (5.61%), and potassium oxide (2.36%) represent the main chemical constituents present in the sediment. The authors characterized the sediment in terms of the content of biogenic compounds: various forms of phosphorus and nitrogen, organic compounds – determined as total organic carbon (TOC), selected metals, and the content of individual elements (carbon, hydrogen, oxygen, nitrogen, sulfur). In addition, the sludge samples were also characterized in terms of calorific value, ash content, water content, and heat of combustion. Discharging WTP sludge into rivers, ponds, and lakes or storing dewatered sludge is an environmentally unfriendly form of disposal for this type of waste. The authors see the possibility of conducting further research on using WTP sludge in wastewater treatment, removing heavy metals from aqueous solutions, producing cement and construction materials, and recovering or recycling.

Study on Impact Resistance of Alkali-Activated Slag Cementitious Material with Steel Fiber

Alkali-activated slag cementitious materials (AASCMs) use alkaline activators to activate blast furnace slag and waste slag to replace traditional Portland cement, which can reduce CO2 emissions. An impact resistance test and scanning electron microscopy (SEM) microscopic performance analysis of alkali-activated slag cementitious material specimens with four different steel-fiber contents are performed. The effects of steel-fiber volume content and strain rate on the dynamic elastic modulus Ed, dynamic compressive strength σd, dynamic peak compressive strain εc, and energy absorption of the AASCM-SS are studied. The results indicate that the dynamic elastic modulus Ed, dynamic compressive strength σd, and energy absorption of the AASCM-SS increase with the increase of strain rate, and the dynamic peak compressive strain εc decreases with the increase of strain rate. The dynamic elastic modulus Ed, dynamic compressive strength σd, and dynamic peak compressive strain εc of the SS-AASCM increase first and then decrease with the increase of steel-fiber content. When the steel-fiber content is 0.5%, the σd and εc of the AASCM-SS are the highest, increased by 9.9% and 19.3%. The energy absorption of AASCM-SS increases with the increase of steel-fiber content. A dynamic constitutive model of the FR-AASCM considering the influence of damage, strain rate, and steel-fiber volume fraction is established. The proposed constitutive model is in acceptable agreement with the experimental AASCM-SS dynamic stress–strain curve, and the correlation coefficient is 0.91.

Enhanced leaching control of chromium, antimony, and chlorine utilizing CO2-curing slag-fly ash-based agent

This study strives to address the technical bottleneck posed by leaching risks associated with Cr, Sb, and soluble Cl in low-carbon slag-fly ash-based cementitious materials (BFCM) according to our previous research. The introduction of CO2 activation significantly enhances the dissociation of BFS, leading to superior mechanical performance and environmental safety of BFCM. LT3 matrix of BFCM (BFS: MSWI fly ash: FGDG: cement= 42: 20: 10: 28) showed excellent compressive strength (46.79Mpa at 7d). The LT3 matrix enables effective solidification/stabilization (S/S) of Cr, Sb, and Cl with CO2-curing (7d). Furthermore, the leaching concentrations of Sb and Cl within LT system, exhibit a positive correlation, while they demonstrate a negative correlation with Cr. Sb primarily relies on the levels of Ca2+ and OH- in the leaching solution, critical for the formation and stability of Ca-Sb precipitation based Visual MINTEQ fitting. CO2-curing enhances the S/S efficiency of Cl by accelerating the ion exchange of Cl- with OH- in C-A-H and SO42- in the AFm phase, leading to the formation of functional Friedel’s salt. This process is characterized by OH- dissolution and subsequent CaSO4 crystallization. The LT system activated by CO2 exhibited accelerated reaction kinetics relative to traditional hydration (LH), characterized by rapid BFS dissociation and the formation of functional hydration products such as ettringite, C-(A)-S-H, and Friedel's salt. This process also reduced macropores and capillary pores of BFCM, a positive correlation exists between the relative macropore content and Cl leaching levels, whereas the decrease in both macropores and capillary pores is associated with ettringite crystallization.

Valorization of Sugarcane Bagasse Ash as an Alternative SCM: Effect of Particle Size, Temperature-Crossover Effect Mitigation & Cost Analysis

The construction industry faces increasing pressure to reduce its environmental impact while meeting the growing demand for infrastructure. One approach to achieving this goal is the use of industrial waste as a replacement for traditional supplementary cementitious materials (SCMs). This study investigates sugarcane bagasse ash (SCBA), addressing the future scarcity and increased cost of other commonly used SCMs. Despite existing literature, the use of SCBA is hindered by several unknowns. This research evaluates SCBA’s performance in mortars, focusing on the effects of curing temperature and particle size variation. Mortar samples were prepared with SCBA replacements from 0% to 30% by mass of cement and cured at 21 °C and 45 °C for 7, 28, and 90 days. The results suggest potential for SCBA replacement up to 30%, emphasizing its sustainability and economic benefits. A cost analysis was also conducted, demonstrating the economic viability of SCBA as an alternative to traditional cement for practical applications.

Review of Recent Developments in Tensile Properties of Engineered Geopolymer Composites

Engineered Cementitious Composite (ECC) is a type of highly ductile cementitious material. However, due to its characteristics of high energy consumption and high carbon emissions, it is necessary to seek a new type of low-carbon and environmentally friendly substitute. Engineered Geopolymer Composite (EGC), as a promising construction material for replacing ECC, has broad application prospects. Through visual analysis of the relevant literature in Web of Science, it was discovered that the research on EGC mainly concentrates on aspects such as the types of precursors, the chemical composition of the alkali-activated solution, and the related parameters of fibers. This paper mainly combines the relevant experimental research data on the tensile properties of EGC conducted by scholars at home and abroad, and focuses on analyzing the influence of precursor types, the chemical composition of the alkaline activator, and fibers on the tensile properties of EGC. The statistical results indicate that fly ash and ground granulated blast-furnace slag (GGBFS) are the most commonly used precursor materials. Replacing an appropriate amount of fly ash in the precursor with GGBFS can significantly enhance the tensile strength of EGC. The type of alkaline activator and its molarity have a relatively obvious influence on the tensile properties of EGC. An increase in the molarity of NaOH within a certain range can enhance the tensile strength of EGC. Furthermore, the incorporation of fibers, especially synthetic fibers such as polypropylene (PP) and polyvinyl alcohol (PVA) fibers, as well as inorganic fibers such as glass fibers (GF) and carbon fibers (CF), can effectively enhance the tensile strength and tensile strain capacity of EGC. The use of hybrid fibers may further improve the tensile properties.

Effect of Olive Waste Ash as a Partial Replacement of Cement on the Volume Stability of Cement Paste

Over the last decades, concrete has been excessively prone to cracks resulting from shrinkage. These dimensional changes can be affected by the incorporation of supplementary cementitious materials. This work used olive waste ash (OWA), which could substantially tackle this problem and achieve sustainability goals. For this issue, five cement paste mixes were prepared by replacing cement with OWA at different percentages varying from 0 to 20% by weight with a constant increment of 5%. The water-to-cement ratio was 0.45 for all mixes. Compressive strength and flexural strength were investigated at 7, 28, and 90 days. In addition, three shrinkage tests (drying, autogenous, and chemical) and expansion tests were also conducted for each mix and measured during 90 days of curing. The experimental findings indicated that there was a loss in compressive and flexural strength in the existence of OWA. Among all mixes containing OWA, the samples incorporating 10% OWA exhibited maximum strength values. Furthermore, the chemical and autogenous shrinkage decreased with the incorporation of OWA. However, the drying shrinkage decreased at lower levels of substitutions and increased at higher replacement levels. In addition, there was a growth in expansion rates for up to 10% of OWA content, followed by a decrease at higher levels (beyond 10%). Additionally, correlations between these volumetric stability tests were performed. It was shown that a positive linear correlation existed between chemical shrinkage and autogenous and drying shrinkage; however, there was a negative relationship between chemical shrinkage and expansion.

Study on the strength characteristics and microscopic mechanism of sewage sludge ash modified lime soil

The large amount of sewage sludge ash (SSA) generated by incineration treatment of sewage sludge each year can seriously pollute the environment, and there is an urgent need to seek an effective resource utilization method for SSA treatment. SSA has the significant pozzolanic activity, and can be used as an auxiliary cementitious material. For that, SSA was adopted to modify lime soil in this work. The strength characteristics of SSA modified lime soil (SLS) were investigated by conducting unconfined compressive strength test and unconsolidated-undrained triaxial compression test, and X-ray diffraction (XRD) test and scanning electron microscopy (SEM) test were conducted to investigate the mineral composition, microstructure and porosity of SLS. It is observed that the unconfined compressive strength (UCS) increases first and then decreases with increasing SSA content in the range of 0–20 %, and reaches the maximum value while SSA content is 15 %, which increases by 25 % at the curing age of 28 days comparing to the specimen without SSA. Additionally, the triaxial strength and cohesive force both have the same change law as UCS with SSA increasing, and 15 % can be used as the optimal content of SSA to modify lime soil. The added SSA can promote the pozzolanic reaction, and more hydration products fill the specimen porosity so that the specimen strength can be improved. Furthermore, the porosity of SLS decreases first and then increases with SSA content increasing, and there is a linear relationship between the porosity and strength of SLS. Finally, a simple function is proposed, which can simulate the quantitative relationship between UCS and the triaxial strength with satisfying accuracy. Generally, the research results can be used as a reference for the application of SSA in soft soil foundation treatment.