Cost Of Construction Materials Research Articles

Effect of alkali treatment and fibre length on agave/mortar composite properties

The use of natural vegetable fibres to reinforce cement and cement mortar is well studied in the literature. This paper focused on the efficient deployment of Agave americana L. fibre by using it as reinforcement in cement mortar. Two parameters that affect the mechanical properties of composites were taken into account, mainly fibre length and fibre pre-treatment. The tensile and flexural strengths of the specimens were determined. Results of this study indicated that the fibre length influences both flexural and tensile properties. When treated with 2 % NaOH, the tenacity of agave fiber passed from 32 cN/tex to 40 cN/tex and its crystallinity increased from 13 % to 44 %. The fibre length of 20 mm appeared to be the optimum value over which the flexural strength decreased due to the bundling effects of the long fibres. Besides, treating the fibres with an alkaline solution of 2 % NaOH could improve the mechanical properties of agave/mortar composite in such a way that the tensile strength increased from 4.5 MPa to 10.9 MPa for a fiber length of 25 mm. The main result of this study showed the possibility of using Agave americana L. fibres to implement low cost construction materials.

Investigation of material cost of a propane-propylene rectification column

In this study a propane-propylene rectification column was investigated in terms of diameter of the column, number of trays, reflux ratio and the construction material costs of the column. During the calculations the reflux ratio was modified between 8 and 30. The chosen material of the column and trays was 1.4404 grade austenitic steel. The calculation has shown that with higher reflux ratio the diameter of the column and the number of trays were changing. Next, the necessary wall thickness of the shell of the column was determined with strength calculation. A material cost function was also determined with these parameters applying various reflux ratio values. From the results it can be concluded that the optimal reflux ratio is 12, because in this case the material cost function has a minimum point.

Building Safety Evaluation and Improvement for Northern Vietnam Mountainous Environments Empirical Study Combining Japanese Experience with Local Conditions

This study addressed the insufficient structural strength and inadequate disaster resistance in building designs in the mountainous regions of Northern Vietnam. By integrating Japanese construction experience with local conditions, we proposed optimized building structures and simplified safety evaluation methods. Through an analysis of climate, terrain, geological hazards, soil conditions, and construction material costs, building design and foundation construction were optimized, and these optimizations were validated through wind tunnel experiments and finite element analysis. The results indicated that the optimized structures exhibited superior wind load stability, with external wind pressure coefficients ranging from −1.5 to −0.7, compared with the traditional structure’s range of −1 to −3.5. The redesigned foundation improved landslide resistance, reducing excavation and foundation construction costs relative to Japanese methods. The foundation’s safety factor reached 4.42–5.13, surpassing the standard of 2.5, and the retaining wall’s sliding resistance safety factor reached 1.87, exceeding the requirement of 1.5. These enhancements dramatically boosted building safety under extreme weather conditions. This study provides practical solutions for building design in Vietnam’s mountainous regions and serves as a valuable reference for similar research in other developing countries, underscoring significant practical and social implications.

Sustainability and durability performance evaluation of geopolymer concrete with industrial effluent as alternative to conventional river sand

Due to infrastructural development activities, the need for the construction materials increases, because of which most of the naturally available natural resources are over exploited and the cost of construction materials are increased. Therefore, the present study focuses on the use of industrial by-products for the development of concrete and examines the physical, mechanical, durability and sustainable performances. Fly ash (FA) and ground granulated blast furnace slag (GGBS) were employed as binder medium and the industrial effluent sodium silicate waste was used to replace the conventional river sand in the geopolymer concrete (GPC). GGBS was employed as source material for the production of concrete to increase the polymerization reaction process and further, the developed concrete was cured in the ambient condition of temperature range 27 ± 2 °C, in the laboratory. The concentration of the sodium hydroxide (NaOH) in the present study was 12M, and the alkaline solution ratio was 1:1.5. During the production process of sodium silicate solution in the factory, the residue left at the bottom of the boiling hopper were dumped as waste in the open land. GPC gains its strength based on the alumina and silica in the source material and alkaline activator solution, therefore, this industrial waste residue was identified as potential alternative to conventional river sand. The concrete with and without effluent was subjected to two types of acid (Sulfuric acid (H2SO4) and Hydrochloric acid (HCl)) and further to examine the performance of concrete under marine condition, two types of salt solutions, namely, magnesium sulfate (MgSO4) and Sodium Chloride (NaCl) were used, the concentration of acids employed in the present study is 2% and the marine solution is 3.5%. Increase in the proportion of effluent from 0% to 100% decreases the slump value of the concrete. Contrastingly, increasing the proportion of effluent increases the strength of GPC after 28-d of room temperature curing. To examine the performance of the concrete under acidic and marine conditions, average of three concrete specimens were employed and the duration of exposure was considered in the present study starts from 28-d and continues till 360-d. After exposing to acidic environment, mass loss, strength loss and surface modification were examined; the loss in mass was found to be 1.5–3% and the strength loss was found to be 35%–45%. In the case of salt solution exposure, the loss in mass was seen to be 1–2% and whereas in the case of strength, the loss was found to be 30%–42%, respectively. Further, the sustainability aspects of the concrete with industrial effluents were examined in detail; focusing on economic value of the concrete, carbon emission and energy demand during the production of concrete.

Assessing the durability properties of sandcrete blocks incorporating iron filings as fine aggregate

The rising costs of construction materials, particularly sandcrete blocks, necessitate the exploration of cost-effective alternatives. This study examines the feasibility of incorporating iron filings (IF), a by-product of metal workshops, into hollow sandcrete block production and assesses their performance under harsh conditions. IF was used to replace 5–20 % of the fine aggregate component in blocks at a step of 5 %, mixed at a 1:8 ratio, and sized at 450mm×150mm×225mm. The study evaluated the impact of acidic exposure on the density, sorptivity, and compressive strength of these blocks, as well as their sensitivity to elevated temperatures. The results showed that IF blocks had significantly lower density than non-IF blocks, especially those cured with H₂SO₄. For instance, blocks with 15 % IF and cured in 0.3 mol/dm³ H₂SO₄ had a 13.9 % reduction in density. Despite higher acid concentrations, IF samples demonstrated better sorptivity, absorbing water more slowly than non-IF samples. However, exposure to acidic media reduced compressive strength by 1.9 %–47.8 % for HNO₃ exposure and 0.5 %–42.4 % for H₂SO₄ exposure. None of the acid-exposed blocks met the minimum standards for load-bearing (2.5 MPa) or non-load-bearing walls (2.0 MPa) as per NIS standards. Furthermore, the sensitivity of IF sandcrete blocks to changes in compressive strength under elevated temperatures decreased by almost half, from 0.026 to 0.014 MPa/°C, as the curing period increased from 7 to 28 days. Blocks with 5–15 % IF showed improved compressive strength at temperatures below 150 °C, but strength declined sharply beyond this temperature. By utilising IF, a readily available waste material, the implications of the study are significant for promoting a circular economy in the construction industry. However, the performance of the blocks against durability concerns needs to be improved further before integrating such waste materials into developing sustainable and resilient construction materials

Exploring the key risk factors impeding the performance of highway construction projects: an evidence from Nigeria

Purpose Construction projects, and particularly highway infrastructures, are known to be major contributors to the socio-economic growth of developing countries. However, these types of projects are infamous for being highly risky due to the interplay of numerous risk factors. This study aims to explore the key risk factors impacting on the performance of highway infrastructure projects in Nigeria from the contextual viewpoint of key industry stakeholders. Design/methodology/approach Qualitative data was collected using semi-structured interviews. Specifically, 17 in-depth expert interviews were conducted with experienced stakeholders in the highway sector of the Nigerian construction industry. The collected data was transcribed and analysed using an established coding framework (grounded on case study approach, principles of thematic analysis and saliency analysis). Findings Overall, 17 key risks were identified from the data analysis process, and 6 risks were recognised as the most significant, based on the combination of prevalence of occurrence and significance of the coded information. The six top risks were: change in government, corruption, cost of construction materials, inflation, project funding issues and construction project delay. However, the first two of these risks (change in government and corruption) are politically related, which is specific and unique to the setting of Nigeria and thus might be seen as discouraging indicators that could have an impact on attracting foreign investors/contractors to Nigeria. Originality/value The study addressed the gap related with identifying context-specific risk factors impeding the performance of highway projects in Nigeria from the viewpoints of industry experts. It is expected that the findings will provide a better insight into the various risk factors and thus aid relevant policymakers to provide context-specific mitigating strategies.

Determinants of Residential Real Estate Property Prices in Ethiopia: The Case of Bahir Dar City

The Ethiopian real estate industry has grown in the previous two decades, especially in the capital city of the country and regional capitals, including Bahir Dar. Real estate prices have doubled and even tripled in a few years because of different factors. Thus, the purpose of this study is to analyse the factors affecting residential real estate prices in Ethiopia, particularly in Bahir Dar City. For this purpose, the study used both purposive and stratified random sampling techniques. Descriptive and inferential statistics were used to analyze the data, and the ordinary least squares method was used to identify the factors that influence residential real estate prices. The hedonic regression model result reveals that R<sup>2</sup> statistics (0.880) indicate that 88% of the variation in residential real estate prices can be explained by variation in the independent variables. Hedonic regression model results revealed that plot size, floor area, number of rooms, age of the house, external wall finishing material, ceiling finishing material, the direction of the house, distance of the property from the main road, and involvement of brokers in the transaction process, were major micro-factors that had a significant effect on residential real estate prices at the 5% level of significance. Furthermore, the interview results show that the challenges faced by real estate developers mostly include loans and aid issues, high-interest rates, mortgage restrictions, the financial capacity of real estate companies, delays in plan approvals, and rising costs of construction materials are among the major challenges affecting investment in real estate. The study suggests that the municipality of Bahir Dar City should provide an adequate supply of land to real estate developers, improve infrastructure development, and federal and regional governments should provide the credit lending mechanism by lowering interest rate especially for low-income class.

Revitalizing the Indian Real Estate Industry: An Exploratory Study on Mitigating Developer Challenges in a Post-Pandemic World

India's real estate industry is now a vital part of the country's economy, contributing around 50% of its GDP. However, the developers in the real estate sector need help to meet the growing demand for housing and infrastructure. These include the unavailability of land, lack of access to funds, high reliance on physical labour, rising construction material costs, and approval and procedural delays. This paper examines these challenges and their root causes, providing insights on how to address them. It further discusses the impact of the COVID-19 pandemic on the sector. It also discusses various government schemes and policies affecting the real estate sector including the Real Estate (Regulation and Development) Act, 2016, and the Pradhan Mantri Awas Yojana. To further support the sector’s growth, the paper proposes measures such as increasing access to finance, streamlining approval processes, and promoting the use of technology to reduce reliance on physical labour. This paper shall analyse the Indian real estate sector’s challenges, its impact on the country’s economy, and recommendations for sustainable growth.

Asphalt Concrete Production Technology Using Oil Sludge from Zhaik Munay LLP

Oil sludge exhibits a compositional similarity to bitumen, a pivotal constituent in asphalt concrete mixtures. This similarity underscores the potential applicability of oil waste in the production of asphalt concrete, serving not only as an organic binder to fortify indigenous soils but also as a binding agent for the fabrication of organomineral mixtures. The incorporation of oil sludge in road construction endeavors holds promise for the conservation of natural resources, the amelioration of the environmental landscape, and a concurrent reduction in the cost of construction materials. The focus of this study encompasses a comprehensive examination of the physical and mechanical properties pertaining to asphalt concrete of Grade I, Type B. To enhance the performance attributes of asphalt concrete, an additive in the form of oil sludge sourced from ZhaikMunay LLP (Uralsk) was introduced. Various proportions of oil sludge, namely 5%, 10%, and 15%, were incorporated into the asphalt concrete mixture. The utilization of 5% oil sludge elicited negligible alterations in the properties of the asphalt concrete. However, with a 15% addition of oil sludge, discernible reductions were observed in maximum compressive efficiency (0.03% by volume) and shear resistance, indicated by the internal friction coefficient efficiency (0.01% by volume).

Exploring the potential role of decentralised biogas plants in meeting energy needs in sub-Saharan African countries: a techno-economic systems analysis

To achieve the Sustainable Development Goals by 2030, low-income sub-Saharan African countries urgently need to electrify. Biogas production from anaerobic digestion could make a contribution to a solution to improved electricity generation and access in these regions. This study evaluates its feasibility using Malawi as a case study. The aim is to provide households with a continuous supply of gas for cooking and electricity. The study examines different sizes of fixed dome reactors (3, 6, 12 m3) and assumes individual household ownership of 2, 4, and 6 cows. Several feedstocks and conditions are considered, such as cow dung alone, co-generation of cow dung with human faeces, cow dung with grass, and cow dung with maize residue. The economic benefits of selling biogas and fertilisers are calculated, and the cost of construction for different sizes of reactors is determined. Results show that co-generation of cow dung and grass silage in the reactor of 12 m3 with six cows has a positive net present value (NPV) of $8962, while for a small farm with a 6 m3 reactor capacity, co-digestion of cow dung with maize residue is preferable. The feasibility of the technology depends heavily on current national economic conditions, such as inflation, electricity prices, and construction material costs. A sensitivity analysis estimated that a 25% increase in the cost of electricity could increase the net present value (NPV) from − $3345 to $1526 for the generation of biogas from cow dung alone. Overall, this technology could have a significant impact on the lives of low-income households in sub-Saharan Africa by improving their access to electricity and providing a source of income through the sale of biogas and digestate.

Assessment of the split tensile strength of fiber reinforced recycled aggregate concrete using interpretable approaches with graphical user interface

Incorporating recycled concrete aggregates into concrete represents a sustainable approach to mitigate the extraction of natural mineral resources and alleviate the adverse environmental effects associated with the concrete industry. Nevertheless, it encounters challenges due to the vulnerability of the hardened mortar adhering to natural aggregates. Thus, leading to an increased susceptibility to cracking and reduced strength. Therefore, this study utilized machine learning (ML) methods such as gene expression programming (GEP), random forest regression (RFR), artificial neural networks (ANN), ANN-Bagging, and ANN-Boosting models to forecast the split tensile strength (STS) of fiber-reinforced recycled aggregate concrete (FRRAC). To develop the models, 257 data points were gathered from experimental studies, encompassing ten influential input variables and considering the STS as the output variable. The accuracy of the models was assessed using statistical metrics. The five developed prediction models showcased excellent and reliable performance, with an impressive correlation coefficient (R) exceeding 0.80 during training and reaching 0.92 in testing. However, the GEP model outperformed the remaining four models, with an excellent R-value of 0.980 in training and 0.983 in testing. In addition, the standalone ANN model demonstrated performance on par with the ensemble ANN-Boosting model. In contrast, the ANN-Bagging ensemble model outperformed the individual ANN model, showcasing superior prediction accuracy with impressive R-values of 0.952 and 0.975 for training and testing, respectively. Moreover, the feature analysis based on SHapley Additive exPlanations (SHAP) revealed that fiber content, recycled aggregate density, cement, and water have the highest contribution in estimating the STS of FRRAC. Furthermore, a user-friendly graphical interface (GUI) has been developed to simplify the application of machine learning models in predicting the strength properties of concrete. In conclusion, the findings can encourage the utilization of FRRAC in both structural and non-structural reinforced concrete elements. Therefore, promoting the recycling and reuse of construction waste into building materials and thereby reducing environmental impact. Furthermore, incorporating recycled concrete aggregate in construction projects has the potential to decrease construction material costs, as it reduces reliance on natural resources such as natural coarse aggregate.

Modelling Cost-Risk Impact on Nigerian Highway Projects Using Multiple Linear Regression and Artificial Neural Networks

Cost predictive models for highway projects are relatively scarce in developing countries, despite the frequency and magnitude of project cost overruns in such countries. This study identified critical cost risks impacting highway projects and modelled their impacts on the actual cost of the projects. Historical cost data on highway projects published by the Nigerian Federal Ministry of Power, Works and Housing in 2017 served as a preliminary list of projects for the study, while further cost data were obtained from highway engineers and quantity surveyors across Nigeria using the snowballing technique until 103 highway projects were identified. Project participants were purposively chosen to fill out questionnaires on costrisks factors associated with highway construction projects. The relative importance index and Pareto 80/20 rule were used to analyse the collected primary data. Thereafter, multiple linear regression and artificial neural network models were developed. Findings revealed that the increase in the cost of construction materials and labour and the fluctuations in foreign exchange rates were the most significant risks impacting highway project cost performance. A comparison of the models indicated that the artificial neural networks model performed better. Hence, the artificial neural networks model is a superior technique for modelling the relationship between cost risks and cost performance of highway projects.

Optimizing the cost of acquiring construction materials

The article presents selected problems of construction contractors in determining the optimal financial reserve in the bid price/base budget to cover the costs associated with the increase in the cost of construction materials, as well as optimization of the cost of acquiring this price-forming component.The first part of the article ana-lyzes the determinants of changes in the average national prices of materials, labor rates (for general construc-tion and high-standard finishing works) in 2020-2023. The second part of the article indicates the measures that should be taken by the contractor as part of an effective program to manage the acquisition costs of con-struction production factors, in particular, construction materials.

Structures of bored piles: features of installation technology

Currently, pile foundations are often used in engineering practice. Among the modern types of piles used for foundation structures, the option of foundations made of bored piles is definitely popular. They are used for various types of structures: bridges as part of highways, urban ring roads or high-rise buildings. The main problem in these cases is related to a reliable assessment of the bearing capacity of the pile and the development of a cost-effective design solution for foundation structures.
 The studies carried out in this direction confirm that the issue of determining the load-bearing capacity of piles remains relevant both at the stage of developing reliable design solutions and in the process of searching for an economically efficient option of the foundation constructions of buildings and structures.
 Taking into account the design features of bored piles and their installation technology add certain difficulties to the analytical methods of determining the soil bearing capacity of a single pile.
 The practice of using bored piles on construction sites followed by observation of deformations showed that the soil bearing capacity of the piles, determined by the analytical method of standards used at the stage of developing design solutions for foundations, is underestimated. Therefore, the total number of piles in the foundation needs to be optimized according to the results of further field tests. Geometric parameters of piles, such as length and diameter, in some cases can also be reduced at the stage of rationalization of the design solution of the pile foundation, based on the results of field tests. So, as a result, the underestimated value of the load-bearing capacity of bored piles causes an increase in the cost of construction materials, an increase in the cost of installing foundation structures and an increase in the cost of housing for the end consumer.
 The problem of reliable assessment of the soil bearing capacity of piles remains a relevant issue at the moment, as evidenced by the practice of designing foundation structures.
 The paper presents the results of the analysis of the structural features of bored piles, which are aimed at increasing their bearing capacity. Also, the paper examines the features of the technology of installing bored piles, which are determined by both the hydro-geological conditions of the construction site and the need to install the constructive features of the bored pile.

The risks of private sector investment in affordable housing development: An Afrocentric perspective

The state delivery of affordable and sustainable housing continues to be a complicated challenge in Africa, and there is a need to encourage private sector participation. As a result, this study examines the risks associated with private sector participation in affordable housing and supporting infrastructure investment and the strategies towards mitigating the risks from an Afrocentric perspective. The evidence from a systematic literature review was coupled with the opinion of an international expert panel to address the paper’s aim and provide recommendations for developing improved housing and supporting infrastructure in Sub-Saharan Africa. The review outcomes and the qualitative data from the panel discussion were analysed using thematic analysis. The results revealed that market dynamics, land supply and acquisition constraints, cost of construction materials, unsupportive policies, and technical and financial factors constitute risks to affordable housing in the region. Mitigation strategies include leveraging joint efforts, strengths, and resource bases, increasing access to land and finance for private sector participation, developing a supportive government framework to promote an enabling environment for easy access to land acquisition and development finance, local production of building materials, research and technology adoption. In line with the United Nations (UN) Agenda 2030 targets and principles, reforms are required across the housing value chain, involving the private sector and community. Application of the study’s recommendations could minimise the risks of affordable housing delivery and enhance private sector participation.

A database and empirical model for earthquake post-loss amplification

The impact of destructive earthquakes might exceed the local capacity to cope with disasters and lead to an increase in the reconstruction costs. This phenomenon is commonly termed as post-loss amplification, and its main causes include the increase in the cost of construction materials and labor due to the sudden demand, the need to reconstruct following higher standards, or other unexpected costs. We reviewed 70 past earthquakes to identify events where post-loss amplification was observed, and collected a set of seismogenic, socio-economic, geographical, and impact variables for those events. Using this database, we developed two models to predict post-loss amplification, using a composite indicator that reflects the level of destruction in the region, or a parameter that characterizes the frequency of the event. This study indicates increased costs (>10%) for events where the economic losses exceed 1% of the regional gross domestic product, or for events with an estimated return period of at least 10 years. These models can be applied directly in the amplification of economic losses in earthquake scenarios or in probabilistic seismic risk assessment.

Reshaping concrete

Less Economically Developed Countries (LEDCs) struggle to meet the demand for affordable housing in their growing cities. There are several reasons for this, but a major constraint is the high cost of construction materials. In LEDCs, material costs can constitute 60 to 80 percent of the total cost of residential construction. Nonetheless, their construction mimics the materially inefficient practices of the More Economically Developed Countries (MEDCs), which were developed to reduce labor over material costs. As a result, prismatic beams and flat slabs are often used despite their structural inefficiency. The mounting use of steel-reinforced concrete structures in LEDC cities also raises concern for the environmental costs of construction; construction accounts for 20-30 percent of LEDC carbon emissions. This research addresses these challenges with a flexible and accessible methodology for the design and analysis of materially efficient concrete elements that may reduce the economic and environmental costs of urban construction. Designed for the constraints of LEDCs, structural elements are optimized to reduce the embodied carbon associated with the concrete and reinforcing steel while resisting the required loads of a standard building structure. The optimization method includes a novel approach to 3D-shape parameterization, as well as a decoupled analytical engineering analysis method that accounts for the key failure modes and constraints of reinforced concrete design. This method is then built into an open-source toolkit, combined with machine learning for real-time analysis and visualization, and tested using lab- and full-scale prototypes. The goal of this research is to present several generalizable methods that are applicable and accessible to LEDC building designers. These methods can enable the design of concrete elements for multiple performance criteria such as structural behavior, acoustic transmission, and thermal mass. They can also enable an accessible design practice through machine learning, real-time iterative workflows, and visualization tools that include the end-user in the architectural design process. This paper provides a high-level overview of ongoing research that explores how materially efficient design methods might enable sustainable development through low-cost, low-carbon concrete structural systems for affordable housing in LEDCs.

A REVIEW OF THE EFFECT OF ADDITIVES ON THE MECHANICAL PROPERTIES OF LIGHTWEIGHT CONCRETE

Many organizations around the world have recognized lightweight, long-lasting, cost and environmentally-friendly construction materials as a future necessity. The lightweight concrete is manufactured mainly either by replacing the original aggregate with lightweight aggregate or addition foam production materials to concrete mixtures. These additions lead to a decrease in the lightweight concrete density and change mechanical properties such as compressive strength. Therefore, there is much experimental research has been conducted to add different material types that can improve lightweight concrete compressive strength while maintaining low density. In this review, the effect of various additions such as steel fiber, product waste materials, and nano-materials on the lightweight concrete compressive strength and density have been explained. The various effects of these additive materials on lightweight concrete properties, some additives lead to improving the properties of lightweight concrete, while other materials lead to a decrease in those properties, and this depends on the type and amount of material additive, the method lightweight concrete manufacturing, and their mixture composition.

Potential of Calcined and Uncalcined Termite Mounds as Pozzolans in Concrete Mix

High cost of construction materials especially concrete and steel coupled with environmental unfriendliness of cement pose a great problem in building and construction industries. This makes a case for increased advocacy for affordable and environmentally friendly materials. One of the envisaged solutions to this impending problem is the use of termite’s mound as pozzolan. The potential of utilizing these two forms of termite’s mounds in concrete mix design has been exploited in this research work. The compressive strength as well the elemental composition of the various mixes was employed in conjunction with statistical packages to assess the potentials of utilizing termite mound for construction purposes. The compressive strengths were obtained with the aid of universal testing machine of 1000.0kN capacity, the elemental compositions were obtained using Atomic Absorption Spectrophotometer and models were also generated for predicting the compressive strength of either form of the termite’s mound using statistical package for social sciences. The results showed that the calcined form of termite’s mound has a compressive strength of 12.3 N/ mm2 and 12.6 N/mm2 for 5% and 10% percentage replacement respectively these values are comparable to the control mix compressive strength of 15.7 N/ mm2; This is an indication that calcined termites’ mound has a good potential of being used for concrete works in terms of compressive strength. The uncalcined form of termite’s mound has a compressive strength range of 6.9 N/mm2 to 6.0 N/mm2 for 5% and 10% respectively, this shows that its potential of being used for concrete work is very low and could therefore be recommended for making termite mound blocks. The greater compressive strength obtained in calcined termite mounds can be traced to the changes observed in the chemical composition of the calcined and uncalcined termites’ mounds.

Feasibility of utilising waste tyre steel fibres to develop sustainable engineered cementitious composites: Engineering properties, impact resistance and environmental assessment

This study investigates the feasibility of developing sustainable engineered cementitious composite (ECC) with polyvinyl alcohol fibre (PVAF) and recycled tyre steel fibre (RTSF) to reduce the total cost of construction materials and ease the environmental pressure for disposing of waste tyres, putting an emphasis on the engineering properties, impact resistance and environmental assessment. Experimental results reveal that partially replacing PVAF with RTSF can reduce the loss in fluidity and promote flexural performance, while the fibre bridging stress of ECC can reach up to 4.41 MPa because of the enhanced fibre bridging effect. The dynamic compressive properties of ECC present a typical strain rate effect regardless of the fibre content, and the replacement of 0.25 vol% RTSF would cause a further 5.03%–25.55% increase in total dissipation energy within the strain rates of 58.2–124.5 s−1, relative to ECC reinforced by 2.0 vol% PVAF. The synergetic effects of hybrid fibres on dynamic compressive properties of ECC can be explained by the bridging and pull-out effects of PVAF at lower strain rates, as well as the enhanced fibre-to-matrix bonding of hydrophilic RTSF at relatively higher strain rates. Upcycling of waste steel fibres in ECC holds promise as a cost-effective and eco-friendly solution for defence engineering constructions.