Compressive Strength Properties Research Articles

Mechanical properties and microstructure of brick aggregate concrete with raw fly ash as a partial replacement of cement

In response to environmental concerns, researchers explore fly ash as a cement replacement material, and crushed bricks as a cost-effective and load-reducing aggregate, particularly where stone chips are scarce. Therefore, this study investigates the mechanical properties and microstructure of brick aggregate concrete (BAC) with raw fly ash (FA) as a partial replacement of cement. The research involved casting raw FA based BAC (FBAC) cylinders (100 mm diameter and 200 mm height) and prism (100 × 100 × 500 mm) with varying levels of FA (0–25%) using a constant mix proportion by volume of 1:1.5:3 (cement : fine aggregate : coarse aggregate) with a water to binder (w/b) ratio of 0.50 and three curing ages (7, 28, and 90 days). Tests for mechanical properties, including compressive strength, split tensile strength, flexural strength, modulus of elasticity, and Poisson's ratio were conducted to assess the behavior of FBAC, and microstructure were then investigated at 28 days. The results indicated that increasing the FA content up to 15% led to gradual improvement in compressive strength and tensile strength values. At 28 days, the highest values of compressive strength and split tensile strength were observed at 10% FA, with 7.9% and 14.2% increase, respectively, compared to the control concrete. However, the flexural strength of FBAC decreased gradually with cement replacement. On the other hand, modulus of elasticity and Poisson's ratio increased gradually up to 20% and 25% cement replacement, respectively. Up to 15% FA enhanced a more uniform and compact microstructure than that of control concrete. Several equations have been developed to express relationship between compressive strength and other mechanical properties of FBAC. Hence, up to 15% raw FA as a partial replacement of cement improved the mechanical properties and microstructure of BAC.

Sludge-derived biochar as an additive in cement mortar: Mechanical strength and life cycle assessment (LCA)

Given the growing concern about environmental contamination risks, the management of sewage sludge (SS) from wastewater treatment plants is becoming more challenging. Thus, alternative pathways that offer value-added opportunities with minimal environmental impacts are needed. This study investigates the use of 0.52 wt% biochar (BC) powders generated from the pyrolysis of the SS in an N2 or CO2 environment, as an additive in cement mortar mixtures. The effect of dry and pre-wetted BC on the fresh properties, phase formation, compressive and tensile strength properties of cement mortar mixtures were assessed. Thereafter, life cycle assessment (LCA) of Plain and BC-modified mortar mixtures were evaluated, and the environmental impacts arising thereof were quantified. Results showed that whereas the BC had an infinitesimal effect on mix fresh properties, it caused approximately 1734% and 10–18% increases in compressive and tensile strength, respectively. Regardless of the pyrolysis condition, pre-wetted BC had a superior impact on mechanical strength evolution. LCA results showed that except for minor, net increases in particulate matter/water consumption potential, the rest of the impact categories associated with the production of 1 m3 of cement mortar decreased with the addition of the BC. In terms of Global Warming Potential (GWP) per unit 28d compressive strength, the BC-modified mixtures yielded values that were lower than that of the Plain mortar by about 1629%. Therefore, these research findings indicate that the use of SS-derived BC as a low-dose additive in cement composites could help the construction industry mitigate its negative environmental footprints.

Characterization and preparation of eco-friendly foamed concrete using a foaming agent: Optimizing the design by Taguchi analysis

Solid waste management has emerged as the primary global environmental challenge due to the constant production of increasing waste by-products and materials. Using waste materials makes concrete production economical and helps resolve disposal problems. The effects of lightweight foam concrete reinforced with corncob ash (CA) and basalt fibre (BF) on durability, thermal conductivity, and mechanical properties are investigated elaborately in this study. The foam concrete mix is prepared in three series with a foam (F) content of 25, 50, and 75 kg/m3 with and without the CA and BF reference mixes. The mix of corncob ash is chosen as a cement replacement in six different concentrations: 0%, 20%, 30%, 40%, 50%, and 60%. In addition, compositions of 0.5%, 1.5%, and 3% basalt fibre length variation were incorporated into the weight of the cement. Split tensile, compressive, and flexural strengths are determined at 7, 14, and 28 days. The workability, porosity, durability, and thermal characteristics are also examined. This study analyses the confirmation experiment to verify the optimum mix proportions of lightweight foam concrete by applying Taguchi’s experimental design for concrete mixes incorporating by-products as a partial cement replacement. Adding BF improved the mechanical properties of compressive, tensile, and flexural strength, whereas adding CA decreased porosity and thermal conductivity. The 50% CA with 1.5% BF blended concrete with 50 kg/m3 F exhibits high strength compared to 25 and 75 kg/m3 at all ages. The split tensile strength of the F50CA50BF1.5 mix varies from 2.19 MPa to 2.73 MPa, and the compressive strength of 29.13 MPa is higher than that of 14.36 MPa, 18.63 MPa, and 0.88 MPa for the R 25, R 50, and R 75 kg/m3 mixes. The highest mechanical strength and improved durable properties are achieved by replacing 50% of CA and 1.5% of BF with F 50 by-products at all curing periods.

THE EFFECT OF SAWDUST AS SELF-CURING AGENT IN CONCRETE

Concrete is known as the most used material for the construction industry. It is crucial to understand the properties of concrete especially on curing interaction and process. At the water shortage areas, the production of concrete is limited as approximately 230 liters of water is needed for 1 m3 of concrete. The insufficient of water resources has inhibited the building construction and development. Nowadays, researchers have studied and developed curing technology by implementing curing agents into concrete mixes. In this paper, the potential and properties of pre-wetted sawdust as curing agent is investigated and studied. Different curing regimes are implemented and tested to determine the properties of sawdust as curing agent. The results showed that the sawdust has potential to be used for curing agent as the concrete properties have been enhanced with strength index ratios ranging between 0.87 until 0.98. Moreover, the compressive strength and tensile properties were also developed with range ratios between 0.69 up until 0.98, respectively. Hence, the application of pre-wetted sawdust inside concrete is effective for concrete production and highly recommended to be implemented at the water shortage areas.

Impact of Recycled Concrete and Brick Aggregates on the Flexural and Bond Performance of Reinforced Concrete

The construction industry strongly relies on concrete and clay bricks for various applications. The escalating demand for these materials, driven by rapid population growth, has led to resource depletion and increased construction and demolition waste (CDW). Recycling CDW into construction materials, particularly in the form of recycled concrete aggregates (RCAs) and recycled brick aggregates (RBAs), has emerged as a promising solution. This study deals with the structural performance of concrete incorporating RCAs and RBAs. The experimental program encompasses material characterization, concrete mix design, and several tests to assess density, compressive strength, bond behavior, and flexural properties. The results indicate that the replacement of fine natural aggregate (NA) with fine RCAs or RBAs has a negligible impact on density, while the partial replacement of coarse NAs with RAs yields modest reductions in compressive strength. Notably, the bond strength between steel rebar and concrete is influenced by the type and content of RA, with specimens containing RCAs exhibiting a higher bond strength than those with RBAs. Empirical models used to predict bond strength generally align with experimental results, with conservative predictions by some models, such as ACI 318, and overestimation by others, such as models proposed by AS-3600 and CEB-FIB. The flexural tests of beams highlight the variation in stiffness and load-bearing capacity with the proportion of NAs replaced by RAs. While beams with 50% NA replacement demonstrate comparable performance to control beams, those with 100% RA replacement exhibit lower cracking and yielding stiffness. Cracking patterns in beams with RAs differ from control beams, with RA-containing beams showing more cracks and an altered crack distribution. The findings underscore the feasibility of using recycled aggregates in construction, with partial NA replacement offering a balance between sustainable material usage and desired structural properties.

Effect of hybrid fibres on mechanical behaviour of magnesium oxychloride cement-based composites

Magnesium oxychloride cement (MOC) as a green cement has superior mechanical properties such as high strength and quick gain of early strength, however the inherent brittleness has limited its applications where ductility is crucial. To enhance the strength and ductility, a novel hybrid fibre-reinforced MOC-based composite (FRMOC) is developed for the first time using polyethylene (PE) fibres and basalt fibres (BF) to reinforce the MOC. A systematic investigation of the effect of fibre dosage on the flowability, rheological properties, compressive strength, and tensile properties of the developed FRMOC is conducted in this study. The results revealed that the addition of fibre reduces flowability while increasing the yield stress and plastic viscosity. The 1-day compressive strength of the FRMOC reached 68.2–85.4% of the corresponding value at 28 days, demonstrating its high early strength characteristic. The mix with 1.25% PE and 0.75% BF exhibited the maximum compressive strength at all curing ages. All the mixes consistently demonstrated excellent tensile strength and tensile strain capability (ductility), with the tensile strength and tensile strain capacity of 10.95 MPa and 4.41% achieved for the mix of 2% PE fibre, and 8.49 MPa and 2.43% for the mix of 1.25% PE and 0.75% BF respectively. Moreover, a decline in strength characteristics and strain capacity was observed as BF percentages increased. Scanning electron microscope (SEM) analysis was further employed to investigate the morphological changes in the FRMOC matrix at the microscale to discover the fibre reinforcing mechanism.

Analysis of the influence of mechanical properties of cementitious composites using submerged arc welding (SAW) slag recycled aggregate

Concern about the environment and the scarcity of natural resources has led to the search for more sustainable alternatives that minimize the environmental impact of all segments of society. Solid waste recycling has been presented as a good alternative to reduce the impacts generated by the disorderly use of raw materials and the reduction of disposal areas, caused by the large volume of waste disposal generated throughout the year throughout the world. In this context, waste from industries in Brazil is included, especially submerged arc welding (SAW) slag. Waste from these activities is generally solid, with dense materials and variable characteristics in terms of their chemical composition, as they contain different types of elements with a specific function as a load element. These characteristics often present an obstacle to being reused in new materials (flows). Among the various waste generated by various industries, we can mention submerged arc welding (SAW) slag, as being one of the greatest potentials for use, due to often having knowledge of its basic characteristics and properties and its lower degree of contamination by other materials, when compared to other waste, such as construction waste. The objective of this research is to evaluate the mechanical performance characteristics of cementitious matrices made with submerged arc welding (SAW) slag residue and their possible use on a large scale. Cementitious matrices for mortars were manufactured by replacing 0%, 25%, 50% and 75% of the natural fine aggregate with submerged arc welding (SAW) slag residue and a water/cement ratio of 0.48. Through the compressive and tensile strength test, it was observed after 28 days that the cement matrices with replacements obtained increases in the mechanical properties of compressive and tensile strength, compared to the reference cement matrix.

An Experimental Investigation on Partial Replacement of Cement with Powdered Glass Wastes in Paver Block

There is now a significant world-wide interest to solve the environmental problems caused by industrial waste and other materials by including such materials in the manufacture of concrete. This technology has been introduced in India in construction, a decade ago, for specific requirement namely footpaths, parking areas etc. but now being adopted extensively in different uses where the conventional construction of pavement using bituminous mix or cement concrete technology is not feasible or desirable. The characteristics of concrete containing fine crushed glass during its process, the best ratio of fine crushed glass which leads to higher strength of concrete in order to produce concrete blocks, and the effect of waste glass replacement on the expansion caused by Alkali-silica reaction (ASR). This study looked at the feasibility of waste glass inclusion as partial Cement replacement systems. Properties of concrete incorporating waste glass as partial substitution for Cement amounts of 50% and 60% were investigated. The waste glass material used was obtained waste collectors. The results obtained show clearly that glass enhances the compressive strength properties of the final concrete product. The study indicated that waste glass can effectively be used as Cement replacement with little substantial change in strength.

Synergy of micron graphite and fly ash for alkali-activated cementitious material: Electromagnetic absorption characteristics and mechanism

To attain a balance between compressive strength and electromagnetic wave absorption performance, this paper combined two electromagnetic wave loss mechanisms (magnetic loss and electrical loss), and prepared an environmentally friendly alkali-activated slag/fly cementitious material (ASFC) using micron graphite (MG) as the absorber and ground granulated blast furnace slag (GGBS) and fly ash (FA) as the precursors. The conductivity, electromagnetic wave absorption characteristics and compressive strength of ASFC with different ratios of GGBS and FA, MG size (800 mesh, 320 mesh, and 100 mesh), and content were investigated. The results indicated that when the ratio of GGBS and FA was 7:3, natural resonance and eddy current loss contributed to electromagnetic waves absorption at 8.2–11.0 GHz and 11.0–15.5 GHz range respectively. Additionally, the conductivity of MG/ASFC showed typical percolation characteristics, with the percolation threshold reached at a dosage of 3 wt%. In the 8.2–18.0 GHz, the incorporation of MG significantly augmented the conductive loss and polarization loss of ASFC. Furthermore, smaller-size MG was more beneficial for facilitating conductive loss of MG/ASFC among three different sizes. By adding 2 wt% of MG with 800 mesh, MG/ASFC can achieve a minimum reflection loss of −27.8 dB with a bandwidth of 3.0 GHz (Reflection loss ˂-7 dB). However, when compared to other cement-based absorbing materials reported, the MG/ASFC prepared in this experiment demonstrated better compressive strength and wave absorption properties. This finding contributing to a better understanding of green building materials with electromagnetic radiation protection capabilities.

Influence of Recycled High-Density Polyethylene Fibers on the Mechanical and Electrochemical Properties of Reinforced Concrete

The quantity of different plastics generated after consumption is an impact factor affecting the environment, and the lack of recycling generates solid waste. The purpose of this work is to incorporate high-density recycled polyethylene fibers (HDPE) for possible use as concrete reinforcement. Physical and mechanical properties from recycled fibers were analyzed, such as density, absorption, and stress resistance, as well as workability, air content, porosity, concrete compression, and flexural strength properties. Samples were prepared with a low fiber content of 0.2% and 0.4%, as a substitution for sand weight, and lengths of 10 and 30 mm. To study corrosion phenomena, the specimens were exposed to a saline environment containing 3% sodium chloride for 365 days, and the electrochemical techniques including half-cell potential (HCP), electrochemical noise (EN), linear polarization resistance (LPR), and electrochemical impedance spectroscopy (EIS) were applied. The results showed a 4.8% increase in compressive strength with a low fiber percentage and short geometries, while flexural strength increased marginally by 2.3% with small quantities of HDPE fibers. All these factors contribute to greater material durability, less permeability, and crack control. A positive effect of fibers with short dimensions on the corrosion processes of a steel bar was observed, with the fibers acting as a physical barrier against the diffusion of chloride ions.

Effect of sulphonated naphthalene formaldehyde superplasticizer on the mechanical and durability properties of concrete produced using locally sourced fine aggregate from Ghana

The use of superplasticizers is very uncommon in many developing countries. However, its inclusion in concrete enhances concrete's mechanical and durability properties. There is a yawning gap in the literature on the performance of Sulphonated Naphthalene Formaldehyde (SNF) superplasticizers in concrete, especially in the sub-Saharan construction industry where the quality of aggregates used in production is questionable. This study produced two batches of concrete produced with locally sourced pit sand, with characteristic strength of 30 MPa. One batch was without the SNF superplasticizer to serve as a control, whereas the other batch was made with the incorporation of the superplasticizer. The fresh properties of slump and air content and the hardened properties of compressive and flexural strength, elastic, and dynamic moduli were investigated. Further, durability indicators comprising sorption, water absorption, sorptivity, chloride penetration, electrical surface resistivity, and acid attack were investigated. The results of the study demonstrated that the incorporation of SNF superplasticizers in concrete resulted in improved workability and a reduction in ion mobility within the concrete. This was attributed to a decrease in the presence of interconnected pores, leading to notable enhancements in mechanical properties such as increased strength, as well as improvements in both elastic and dynamic moduli. Moreover, concrete containing SNF superplasticizer protects the concrete much better from acid attack than those without SNF superplasticizer. The study recommends the use of SNF superplasticizers in concrete for improved workability, reduced ion movement via fewer interconnected pores, and enhanced mechanical properties, potentially boosting overall durability.

Influence of Starch Powder on Compressive Strength and Microstructural Properties of Geopolymer Composite Materials Based on Metakaolin

The main objective of the present study is the investigation of the behaviour of starch powder incorporated at different levels (0, 5, 10, 15, 20, 25, and 30 wt%) on the compressive strength and microstructural properties of metakaolin-based geopolymers. Sodium silicate with a molar ratio of SiO2/Na2O of 1.6 was used as the hardener and standard metakaolin was used as the aluminosilicate source. The results showed that when metakaolin was replaced by starch from 0 to 15 wt%, the compressive strength increased from 36.50 to 64.12 MPa. When metakaolin was replaced by starch above 15 wt%, the compressive strength decreased from 64.12 to 29.43 MPa. That of the reference geopolymer material is 36.50 MPa.The infrared spectra of the geopolymer composites indicate that the Si-O-C bonds are formed. The thermal behaviour of geopolymer composites containing starch shows a mass loss at around 100 and 278 °C. The geopolymer material without starch only shows a loss of mass at around 100 °C. The micrographs of the geopolymer composite with 15% by weight of starch show that the matrix is more compact, more homogeneous, and denser than the one without starch. On the contrary, possibly due to a large amount of unreacted starch in its network, the micrographs of the geopolymer composite obtained after the incorporation of 30 wt% starch show a heterogeneous microstructure. It can be concluded that suitable starch content for the synthesis of geopolymer composites would be around 15% by weight.

The effect of the freeze-thaw cycle and alkali-silica reaction on self-compacting recycled concrete

This article investigates the durability of recycled self-compacting concrete in relation to its resistance against freeze-thaw cycles and alkali-silica reactions. It explores the properties of fresh concrete, investigates the impact of various additives, and evaluates key factors such as spalling, weight loss, compressive strength, expansion rate, and ultrasonic properties in hardened concrete samples incorporating different levels of recycled aggregates. The findings illustrate the feasibility of achieving self-compacting recycled concrete by increasing the use of superplasticizers and adding 10% beach sand. Furthermore, incorporating 10% micro-silica and 7.5% wollastonite in the recycled mix enhances the strength of all samples, with the 25% recycled material sample demonstrating the highest strength and durability. Despite a decrease in strength and increased expansion as recycling percentages and freeze-thaw cycles rise, the recycled samples maintain acceptable durability. Additionally, this study employs the R programming language to elucidate the relationship between compressive strength and modulus of elasticity, offering valuable insights into recycled concrete performance and behavior.

Marble Powder as a Soil Stabilizer: An Experimental Investigation of the Geotechnical Properties and Unconfined Compressive Strength Analysis.

Fine-grained soils present engineering challenges. Stabilization with marble powder has shown promise for improving engineering properties. Understanding the temporal evolution of Unconfined Compressive Strength (UCS) and geotechnical properties in stabilized soils could aid strength assessment. This study investigates the stabilization of fine-grained clayey soils using waste marble powder as an alternative binder. Laboratory experiments were conducted to evaluate the geotechnical properties of soil-marble powder mixtures, including Atterberg's limits, compaction characteristics, California Bearing Ratio (CBR), Indirect Tensile Strength (ITS), and Unconfined Compressive Strength (UCS). The effects of various factors, such as curing time, molding water content, and composition ratios, on UCS, were analyzed using Exploratory Data Analysis (EDA) techniques, including histograms, box plots, and statistical modeling. The results show that the CBR increased from 10.43 to 22.94% for unsoaked and 4.68 to 12.46% for soaked conditions with 60% marble powder, ITS rose from 100 to 208 kN/m2 with 60-75% marble powder, and UCS rose from 170 to 661 kN/m2 after 28 days of curing, molding water content (optimum at 22.5%), and composition ratios (optimum at 60% marble powder). Complex modeling yielded R2 (0.954) and RMSE (29.82 kN/m2) between predicted and experimental values. This study demonstrates the potential of utilizing waste marble powder as a sustainable and cost-effective binder for soil stabilization, transforming weak soils into viable construction materials.

Impact of ethanol-assisted and non ethanol-assisted mixing methods on the mechanical properties of impregnated polymethylmethacrylate with MgO and Ag nanoparticles

This study aims to elucidate the effect of non ethanol-assisted and ethanol-assisted mixing methods and adding MgO-and Ag-nanoparticles (NPs) into PMMA on flexural strength, impact strength, microhardness (HV) and compressive strength. NPs (1%, 3% and 5% concentrations) were mixed with poly (methyl methacrylate) (PMMA) powder by either using ethanol as a solvent (ethanol-assisted) or without ethanol (non ethanol-assisted). A total of 91 specimens were examined. One- and Two-way ANOVA tests were used to find the effect of mixing methods and concentration of NPs on mechanical properties of PMMA. The results showed an increase of flexural strength for all NPs concentrations (except 1% MgO-NPs) and HV (5% both NPs) in ethanol-assisted groups compared to non ethanol-assisted group (p < 0.05). Furthermore, the combined effects of NPs and mixing methods revealed statistically significant increases in flexural strength and HV in ethanol-assisted group (except in 1% and 3% MgO-NPs) compared to the control group. Meanwhile, no statistically significant differences were detected in impact strength and compressive strength between ethanol-assisted and non ethanol-assisted groups (p > 0.05). The combined effects of NPs and mixing methods presented a statistically significant increase only in compressive strength of 5% of both NPs in ethanol-assisted group in comparison to the control group. Ethanol-assisted mixing of MgO-NPs and Ag-NPs with PMMA showed an increase in the mechanical properties of flexural strength, HV and compressive strength compared to non ethanol-assisted, whereas no improvement in the impact strength property of PMMA was detected. Furthermore, synergetic effects of adding NPs and mixing methods were identified.

CEMENT MORTARS WITH BOMBYX MORI SILK FIBERS WITH DIFFERENT TYPES OF SURFACE TREATMENTS

The incorporation of natural fibers in cement mortars is an important area of research and development within the construction industry, as it seeks sustainable and ecological alternatives to traditional fiber reinforcements. This paper investigated the effects of different treatments on “Bombyx mori” silk fibers on the mechanical strength and durability of cement mortars, at the same time their architectural possibilities were analyzed. The studied fibers were cut to 20 mm in length, then treated with liquid calcium hydroxide, linseed oil and natural rubber latex. Finally, they were placed in the cement matrix in layers and arranged lengthwise. The mechanical performance and durability of the material were studied through the physical properties of water absorption by immersion, the mechanical properties of compressive, flexural, and impact strength at 7, 14, and 28 days of curing were also studied. The study was complemented with a simulation of alkaline environment of cement using a solution based on sodium hydroxide, measuring the degree of accelerated degradability of the fibers through mass loss. Overall, the results demonstrated that the composite material with fibers treated with natural latex and linseed oil exhibited higher flexural, compressive and impact strength and lower water absorption.

COMPRESSIVE STRENGTH OF Ca(OH)2 COMBINED WITH MUSA ACUMINATA AS A PULP CAPPING MATERIAL

Background: The weakness of Ca(OH)2 is its low compressive strength and mechanical properties which can affect the stability of the material to the liquid in the tooth root canal so that it can dissolve the root canal medicament material. Due to the various weaknesses of Ca(OH)2, the researchers are interested in combining Ca(OH)2 with natural ingredients extracted from Musa acuminata (Mauli Banana) stem. Musa acuminata stem extract (MaSE) contains bioactive compounds such as tannins, saponins, alkaloids, flavonoids and lycopene which have antioxidant, anti-inflammatory, antibacterial and anti-viral properties. One of the requirements for pulp capping material is to have sufficient compressive strength, therefore, it is necessary to conduct research to test the value of the compressive strength of the combination of Ca(OH)2 with Musa acuminata stem extract. Purpose: To analyze the compressive strength of the pulp capping material from the combination of calcium hydroxide and Musa acuminata stem extract, with a ratio of 1:1; 1:1.5 ; and 1.5:1. Method: This research is a pure experimental study with a posttest-only design with a control group design, consisting of 4 treatment groups, including: group 1 the combination of Ca(OH)2 with Musa acuminata stem extract at 1:1, group 2 1:1.5, group 3 1.5:1, and group 4 as a positive control. Results: One Way Anova test (p<0.05) which means there is a significant difference. Data analysis was continued with the LSD Post Hoc test (p<0.05) which showed that there were significant differences between groups, between each treatment group. Conclusion: The combination of Ca(OH)2 with 50% MaSE and PG ratio of 1.5 : 1 : 0.375, has the highest compressive strength (1.40 MPa), so it can be concluded that the more Musa acuminata stem extract in the combination, the lower the compressive strength. Keywords : Calcium hydroxide, Compressive strength, Musa acuminata stem extract

Sustainable utilization of concrete slurry waste in eco-friendly artificial lightweight cold-bonded aggregates: An alternative pathway for efficiently sequestrating CO2

Concrete slurry waste (CSW) has the potential of capturing or sequestering CO2. This study designed the low-carbon artificial lightweight cold-bonded aggregates with ultra-high volume of CSW, OSP and MSWIBA (CSW-ALCBAs), and the CO2 sequestrating, compressive strength, and physical properties, leaching toxicity and CO2 emissions of CSW-ALCBAs were investigated. Meanwhile, a novel carbonization device was designed to quantitatively evaluate the potential of CSW-ALCBAs for CO2 adsorption. The results show that both OSP and MSWIBA have the effect of enhancing the CO2 sequestration of CSW-ALCBAs. Besides, the strength, water absorption and apparent density of CSW-ALCBAs also satisfy the demands of GB/T 17461.1–2010. CSW-ALCBAs also exhibit excellent ability to solidify heavy metals and the removal rate of heavy metals is above 80% excepting Cr. ALCBAs with 85% CSW+5% OSP+10% MSWIBA can absorb 29.1313 kg of CO2 (1000 kg ALCBAs), has the highest compressive strength of 1.3 MPa after curing 28 days, water absorption rate is 15.05% and apparent density is 1.3318 g/m3. Overall, this innovative design of CSW-augmented ALCBAs can open up a new area of CSW application that develops technically feasible and cost-efficient carbon-negative building materials.

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.

Direct electrospinning of reconstructable PVDF-TrFE nanofibrous mat onto conductive cement nanocomposite for triboelectricity-assisted net zero energy structure

As interest in harvesting green energy and utilizing renewable energy in the building sector has increased, the concept of Net Zero Energy Structure (NZES) has been highlighted. In this study, a strategy to develop the sustainable triboelectricity-assisted NZES is proposed. The multi-walled Carbon nanotube (MWCNT)-incorporated Cement Composite (CCC) is adopted as the structural/electrical member of the triboelectric nanogenerator (TENG) and the polyvinylidene difluoride-trifluoroethylene (PVDF-TrFE) nanofiber is directly electrospun onto the surface of CCC to act as the contact layer of the CCC-based TENG. The optimal concentration of incorporated MWCNT, CMC, is determined to be 1 vol%, considering the compressive strength and electrical property of CCC. The conditions of the electrospinning process for configuring the electrospun PVDF-TrFE nanofibrous mat on the surfaces of CCCs with various shapes are investigated. The electrical output performance of the CCC-TENG is characterized by varying the various environmental and operational parameters. The direct electrospun PVDF-TrFE nanofibrous mat on the CCC-TENG significantly increases the output voltage to approximately 6 times that of flat TENG. The maximum peak power generated from CCC-TENG reaches 60.9 μW when the connected load resistance is 50 MΩ. Furthermore, as a proof-of-concept, the reconstructability of the PVDF-TrFE nanofibrous mat using the direct electrospinning process, as well as the restorations in terms of surface micro/nanostructures and electrical output performance, are demonstrated. Given the wide range of applications of cement and various functionalities of direct electrospinning technology, the sustainable triboelectricity-assisted NZES with CCC and direct electrospun PVDF-TrFE nanofibrous mat is expected to have great potential to take a step toward the development of sustainable Net Zero Energy Community in the future.