Retraction Note: Performance of sustainable self-compacting fiber reinforced concrete with substitution of marble waste (MW) and coconut fibers (CFs)

[EN] The Editors have retracted this article. After publication concerns were raised that the XRD spectra in Fig. 8 are identical. The authors are unable to provide the original data for examination. In addition, an investigation by the Editors has shown inappropri- ate changes in authorship during the review process. The Editors no longer have confidence in the results and conclusions presented. Jawad Ahmad disagrees with this retraction. Fahid Aslam and Mohamed Hechmi El Ouni did not respond to cor- respondence from the Editors about this retraction. The Editors were not able to obtain current email addresses for Rebeca Martinez-Garcia and Khalid Mohamed Khedher

Mechanical performance of concrete reinforced with polypropylene fibers (PPFs)

[EN] Fibers are one of the most prevalent methods to enhance the tensile capacity of concrete. Most researchers focus on steel fiber reinforced concrete which is costly and easily corroded. This study aims to examine the performance of polypropylene fiber reinforced concrete through different tests. PPFs were added into concrete blends in a percentage of 1.0%, 2.0%, 3.0%, and 4.0% by weight of cement to offset its objectionable brittle nature and improve its tensile capacity. The fresh property was evaluated through slump cone test and while mechanical strength was evaluated through compressive strength, split tensile strength flexure strength, and flexure cracking behaviors after 7-, 14-, and 28-days curing. Results indicate that slump decrease with the addition of PPFs while fresh density increase up to 2.0% in addition to PPFs and then decreases. Similarly, strength (compressive strength; split tensile strength, and flexure strength) was increased up to 2.0% addition of PPFs and then decrease gradually. It also suggests that Ductility; first crack load, maximum crack width, and load-deflection inter-relations were considerably improved due to incorporations of PPFs.SIThe author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: Deanship of Scientific Research at King Khalid University for funding this work through group research program under grant number RGP. 2 /71/42

Mechanical properties and durability assessment of nylon fiber reinforced self-compacting concrete

[EN] The higher paste volume in Self Compacting Concrete (SCC) makes it susceptible to have a higher creep coefficient and cracking and has brittle nature. This brittle nature of concrete is unacceptable for any construction industry. The addition of fibers is one of the most prevalent methods to enhance the ductile and tensile behavior of concrete. Fibers reduce the cracking phenomena and improve the energy absorption capacity of the structure. Conversely, the addition of fibers has a negative impact on the workability of fresh concrete. In this research work, a detailed investigation of the influence of Nylon fibers (NFs) on fresh properties, durability, and mechanical properties of SCC was carried out. NFs were added into concrete mixes in a proportion of 0.5%, 1%, 1.5%, and 2% by weight of cement to achieve the research objectives. Durability assessment of modified SCC having Nylon fibers was performed using water absorption, permeability, carbonation resistance, and acid attack resistant. Mechanical tests (compressive and tensile) were conducted for modified as well as control mix. Test results indicate that the passing and filling ability decreased while segregation and bleeding resistance increased with NFs. Furthermore, test results showed a significant increase in strength up to 1.5% addition of nylon fibers and then strength decreases gradually. Durability parameters were significantly improved with the incorporation of NFs relative to the control mix. Overall, this study demonstrated the potential of using nylon fibers in self-compacting concrete with improved durability and mechanical properties.SIThe author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: The authors extend their appreciation to the Deanship of Scientific Research at King Khalid University for funding this work through group research program under grant number RGP. 1/100/42 and Taif University Researchers Supporting Project (number TURSP- 2020/276), Taif University, Taif, Saudi Arabi

Eco-friendly incorporation of crumb rubber and waste bagasse ash in bituminous concrete mix

The consumption of waste materials in the construction sector is a sustainable approach that helps in reducing the environmental pollution and decreases the construction cost. The present research work emphasizes the mechanical properties of bituminous concrete mix prepared with crumb rubber (CR) and waste sugarcane bagasse ash (SCBA). For the preparation of bituminous concrete mix specimens with CR and SCBA, the effective bitumen content was determined using the Marshall Mix design method. A total of 15 bituminous concrete mix specimens with 4%, 4.5%, 5%, 5.5% and 6% of bitumen content were prepared, and the effective bitumen content turned out to be 4.7%. The effect of five different CR samples of 2%, 4%, 6%, 8% and 10% by weight of total mix and SCBA samples of 25%, 50%, 75% and 100% by weight of filler were investigated on the performance of bituminous concrete. A total of 180 samples with different percentages of CR and SCBA were tested for indirect tensile strength (ITS) and Marshall Stability, and the results were compared with conventional bituminous concrete mix. It was observed that the stability values rose with an increase in CR percentage up to 6%, while the flow values rose as the percentage of SCBA increased in the mix. Maximum ITS results were observed at 4% CR and 25% SCBA replacement levels. However, a decrease in stability and ITS result was observed as the percentages of CR and SCBA increased beyond 4% and 25%, respectively. We concluded that the optimum CR and SCBA content of 4% and 25%, respectively, can be effectively used as a sustainable alternative in bituminous concrete mix

Characterization of high-performance concrete using limestone powder and supplementary fillers in binary and ternary blends under different curing regimes

Although the dumping of waste generated by industries in the environment poses a hazard, it is feasible to use waste and unused materials to manufacture high-performance concrete. By recycling these wastes in binary and ternary blends, sustainable and durable concrete mixtures can be created, resulting in the development of sustainable concrete structures. Therefore, a research project was undertaken to develop high-performance concrete (HPC) using available supplementary and waste materials, such as fly ash (FA), silica fume (SF), Quartz filler (QF), and limestone powder (LSP), as partial replacements for cement in binary and ternary blends under various curing conditions. Different percentages (5, 8, 10, 15, 20%) of the supplementary materials were mixed in binary and ternary combinations to determine the optimal dosage for high-performance concrete. The fresh and hardened properties of the concrete were evaluated using various tests, including slump, compressive strength, rapid chloride ion permeability, porosity, and drying shrinkage tests. The prepared concrete specimens were tested using various concentrations of binder replacement in binary, ternary, and quaternary combinations. The results showed that incorporating quartz filler as a partial replacement of cement up to 8% yielded positive results regarding mechanical properties. However, all mixtures containing different dosages of SF, QF, FA, and LSP demonstrated significant improvement in durability-related properties under normal and high-temperature curing conditions. Interestingly, the porosity of mixtures incorporating fly ash and LSP showed a slight increase compared to identical specimens under normal curing conditions. Moreover, the drying shrinkage behavior of ultrafine fillers (QF, SF, LSP, FA) indicated that their incorporation led to an increase in the shrinkage of high-performance mixtures under normal and high-temperature curing conditions. Binary and ternary blends incorporating QF, LSP, and SF showed an increase of around 5–8% in shrinkage under high-temperature curing compared to identical specimens under normal curing conditions. Therefore, it can be concluded that QF, LSP, SF, and FA can be efficiently used to produce high-performance cementitious composites, leading to sustainable concrete material

Comparative analysis of enriched flyash based cement-sand compressed bricks under various curing regimes

This study investigates the substitution of traditional burnt clay bricks (BCB), used since 7000 BCE, with environmentally friendly Fly Ash-Cement and Sand Composite Bricks (FCBs), utilizing industrial waste like Coal Fly Ash (CFA) from thermal power plants. The research encompasses two phases: the first involves experimental production of FCBs, while the second focuses on optimizing FCBs by varying CFA (50%, 60%, 70%), Ordinary Portland Cement (OPC) content (9%–21%), and incorporating stone dust (SD) and fine sand. Comprehensive tests under normal and steam curing conditions, adhering to ASTM C 67-05 standards, include X-Ray Diffraction (XRD), Energy Dispersive X-Ray (EDX), and Scanning Electron Microscopy (SEM) analyses. Results indicate that steam curing enhances early strength, with an optimized mix (MD: 5S) achieving a compressive strength of 15.57 MPa, flexural strength of 0.67 MPa, water absorption rate of 20.08%, and initial rate of water absorption of 4.64 g/min per 30 in2, devoid of efflorescence. Notably, a 9% OPC and 50% CFA mix (MD: 1S) shows improved early strength of 4.95 MPa at 28 days. However, excessive CFA replacement (70%) with lesser cement content negatively impacts physio-mechanical properties. This research underscores the potential of FCBs as a sustainable and economically viable alternative to BCBs in the construction industry

Exploring the feasibility of utilizing high plastic clays as an alternative material to bentonite clay in the production of ceramic tile: Advancing towards efficient life cycle cost

The environmental challenges and high cost of raw materials (i.e., bentonite clays) for the production of ceramic tiles raise concerns for the ceramic industry to look for alternative materials. Therefore, the current research aimed at exploring the possibility of using high plastic clays as a replacement for Bentonite clay in the manufacturing of ceramic tiles. Two different types of high plastic clay in different proportions (i.e. 0–5 %) were used in the preparation of ceramic tiles. A comprehensive material characterization, shrinkage, visual index, flexural strength, water absorption, and microstructural investigation was carried out. The results revealed that the incorporation of plastic clays RC1 from 1 % to 5 % showed a decrease in the flexural strength of ceramic tiles as compared to that of ceramic tiles with bentonite clay. The water absorption of ceramic tiles using RC1 increased with the incorporation of high plastic clays for high plastic clays. However, specimens with all replacements of bentonite clay with high plastic clays showed flexural strength greater than the minimum specified limit of ISO 10545-4. Moreover, it was observed that the replacement of bentonite clay with high plastic clays exhibited higher shrinkage. Further, the visual index of all the specimens did not show any sign of the presence of black core in the ceramic tiles incorporating high plastic clays. The life cycle assessment (LCA) was carried out for the possible utilization of high plastic clays in place of bentonite clay to produce ceramic tiles. The results showed that less than 5 % high plastic clay can effectively be used for manufacturing ceramic tiles leading to economical and sustainable construction products. Hence, it can be concluded that the high plastic clays can be utilized as an alternative to bentonite clay material for manufacturing sustainable ceramic tile leading to sustainable finishes in construction

Characterization and economization of cementitious tile bond adhesives using machine learning technique

Cementitious Tile Adhesives (CTAs) play a key role in ensuring the elegant outlook of buildings by improving the serviceability of various tile applications, hence making them an integral part of the dry-mix mortar industry with a significant market share globally. However, CTAs require special raw material for their production, making them a less economical option for sustainable construction applications. Hence, the current research work undertook an effort to explore the potential of different type of fine materials to produce CTAs to obtain a cheap value-added product. A total of 36 mixture proportions were prepared with six different sources of fine aggregates (i.e., silica sand, quartz sand, dune sand, river sand 1, river sand 2, and river sand 3), with six varying binder-to-fine aggregates ratios, and their mechanical strength parameters were evaluated. Further microstructure analysis was performed for fine aggregates, and best and worst performing mixture proportions to gain a deep understanding about their mechanical performance. The results revealed that the mixture proportions utilizing silica sand outperformed all other formulations in terms of compressive strength, and tensile strength with a value of 25.28 MPa, and 1.35 MPa, respectively, while dune sand performed the best in terms of shear strength 1.92 MPa with cement content of 40 % at 28 days. Moreover, microstructural investigation also showed the better microstructural performance of silica sand as compared to that of all other sources of sand. To increase the applicability of the undertaken research project, an Artificial Intelligence (AI) based neural network model, along with predictive equations, was developed for the prediction of compressive strength (R2 = 0.9831), shear strength (R2 = 0.9808), and tensile strength (R2 = 0.9862). Hence, it can be concluded that the current research work provides a foundation for an effective product development process to produce tile bond adhesives using different type of raw materials available leading to economical and sustainable manufacturing of cementitious adhesives

Predicting the performance of existing pre-cast concrete pipes using destructive and non-destructive testing techniques

One of the most significant and critical urban assets for a sustainable community is the sewer pipeline network and water distribution system. Water sewer networks and distribution systems have a definite service life span to provide continuous facilities to end users. Therefore, it is pertinent to continuously evaluate the condition of water and sewer concrete pipelines to ensure the reliable, sustainable, and cost-efficient transport of water and sewerage for the safety of society. The condition assessment is commonly carried out by visual observations followed by some non-destructive testing methods. However, it is the need of the hour to shift assessment methods to advance assessment techniques to save time and money for our community. Currently, in this project, the condition assessment of pre-cast concrete pipes was carried out by destructive and non-destructive methods. Different test trials i.e., ultra-sonic pulse velocity, Schmidt hammer also known as rebound hammer test, visual inspection, three edge bearing test, and core cutting test on the old buried and new concrete pipes were performed. It was observed that concrete used for the construction of existing precast concrete pipes still has better quality indices after 20 years as compared to that of concrete of new pipes. However, steel has deteriorated with time and clear corrosion of steel was identified in existing pre-cast concrete pipes. At the same time, it was observed that there should be an automated mechanism to continuously asses the condition of pre-cast existing pipes which will address the sustainable development goals (SDG 6, 9, 11). Consequently, it can be said that condition assessment of pre-cast concrete pipes will lead to sustainable societies and infrastructure

Impact Resistance of Styrene–Butadiene Rubber (SBR) Latex-Modified Fiber-Reinforced Concrete: The Role of Aggregate Size

Improvements in tensile strength and impact resistance of concrete are among the most researched issues in the construction industry. The present study aims to improve the properties of concrete against impact loadings. For this purpose, energy-absorbing materials are used along with fibers that help in controlling the crack opening. A polymer-based energy-absorbing admixture, SBR latex, along with polypropylene fibers are used in this study to improve the impact resistance. Along with fibers and polymers, the effect of the size of aggregates was also investigated. In total, 12 mixes were prepared and tested against the drop weight test and the Charpy impact test. Other than this, mechanical characterization was also carried out for all the 12 concrete mixes. Three dosages of SBR latex, i.e., 0%, 4%, and 8% by weight of cement, were used along with three aggregates sizes, 19 mm down, 10 mm down, and 4.75 mm down. The quantity of polypropylene fibers was kept equal to 0.5% in all mixes. In addition to these, three control samples were also prepared for comparison. The mix design was performed to achieve a normal-strength concrete. For this purpose, a concrete mix of 1:1.5:3 was used with a water to a cement ratio of 0.4 to achieve a normal-strength concrete. The experimental study concluded that the addition of SBR latex improves the impact resistance of concrete. Furthermore, an increase in impact resistance was also observed for a larger aggregate size. The use of fibers and SBR latex is encouraged due to their positive results and the fact that they provide an economical solution for catering to impact strains. The study concludes that 4% SBR latex and 0.5% fibers with a larger aggregate size improve the resistance against impact loads