Experimental and GEP-based assessment of steel fiber-reinforced self-compacting concrete containing waste glass aggregate and silica fume
Naser Safaeian Hamzehkolaei
Iman Afshoon Amirhossein Davarpanah Tanha Ghochan
Aug 2026· Multiscale and Multidisciplinary Modeling Experiments and Design· Vol 9· 1 citation· 82 references
Abstract
This study investigates the combined use of waste glass aggregate (WGA, 0–60% volumetric replacement of natural coarse aggregate) and silica fume (SF, 0–15% replacement of cement) in steel fiber-reinforced self-compacting concrete. The experimental program covered fresh, mechanical, and durability properties, along with production cost, embodied CO₂, and scanning electron microscopy (SEM) observations. The results showed that 15% SF improved strength and durability, whereas WGA contents above 45% reduced fresh performance. The optimum mixture, containing 15% SF and 30% WGA, increased the 90-day compressive, splitting-tensile, and flexural strengths by 23.72%, 28.90%, and 16.50%, respectively, compared with the control. This mixture also maintained surface water absorption below 7.81% and ultrasonic pulse velocity (UPV) values of 3532–3974 m/s. Even at 60% WGA and 15% SF, production cost and embodied CO₂ were reduced by 4.59% and 5.03%, respectively. SEM observations showed that high WGA contents increased voids, microcracks, and ettringite formation, which contributed to strength loss. Gene Expression Programming (GEP) models were developed using WGA, SF, and durability-related indicators as input variables. The models showed reliable predictive performance for strength, absorption, and water penetration depth. Overall, the findings support the practical use of WGA and SF for producing more sustainable and cost-effective self-compacting concrete.
The construction industry's reliance on ordinary Portland cement (OPC) is a major contributor to global anthropogenic CO₂ emissions, while plain concrete's inherent brittleness and low tensile capacity remain persistent structural limitations. This study presents an experimental investigation into a sustainable hybrid fiber-reinforced concrete (HFRC) of M30 grade, formulated by partially replacing cement with Ground Granulated Blast Furnace Slag (GGBS, 20–50% by weight) and silica fume (5–25% by weight), together with a fixed 2% (by volume of coarse aggregate) hybrid dosage of steel and polypropylene fibers. Six mix combinations were cast and evaluated for compressive, flexural, and split tensile strength at 7, 14, 28, and 60 days of water curing. Compressive strength increased consistently with binder replacement up to 50% GGBS and 20% silica fume, after which higher silica fume content (25%) reduced strength due to workability loss and particle agglomeration. The mix containing 50% GGBS, 20% silica fume, and 2% hybrid fiber (designated M5) produced the best overall performance, reaching 36 MPa compressive strength, 5.3 MPa flexural strength, and 4.1 MPa split tensile strength at 28 days, rising further to 40 MPa, 5.7 MPa, and 4.5 MPa respectively at 60 days. Relative to the mix with the lowest replacement level (M1: 20% GGBS, 5% silica fume), mix M5 showed gains of approximately 24% in compressive strength, 29% in flexural strength, and 41% in split tensile strength at 28 days. The results confirm that the combined pozzolanic action of silica fume and GGBS densifies the cementitious matrix, while the hybrid steel–polypropylene fiber system restrains crack propagation and improves post-cracking ductility. The study establishes 50% GGBS with 20% silica fume and 2% hybrid fiber as the optimum replacement level for producing high-performance, low-carbon M30 structural concrete.
Keywords: Sustainable concrete; Hybrid fiber reinforcement; Ground Granulated Blast Furnace Slag (GGBS); Silica fume; Compressive strength; Flexural strength; Split tensile strength.
Dasari Devika, Dr. Subash Chandra Bose· International Journal of Cre...· 0 citations
This study investigates the combined effects of waste glass powder (WGP) and waste tire fiber aggregate (TFA) on the mechanical and microstructural performance of fly ash (FA)–ground granulated blast furnace slag (GGBS)-based geopolymer concrete (GPC). Previous studies generally examined WGP and TFA separately, therefore, limited information is available regarding their combined influence on geopolymer concrete. The novelty of this research lies in evaluating the synergistic effects of WGP and TFA within a unified experimental framework to enhance sustainability and mechanical performance. In this research, the optimal WGP content was determined using slump and compressive strength tests at 3%, 6%, 9%, and 12% replacement levels. Subsequently, TFA contents of 5%, 10%, 20%, and 30% were incorporated into the optimum FA–GGBS–WGP blend as partial fine aggregate replacement. An alkaline activator consisting of Na2SiO3 and NaOH at a 2:1 ratio with a 12 M concentration was used. The results showed that 9% WGP achieved optimal performance, increasing slump and improving 28-day compressive strength by 6% compared with the control mix. Incorporation of Low TFA contents (5–10%) enhanced both tensile and flexural strengths, with 10% TFA producing the highest improvements of 27% in tensile strength and 30% in flexural strength, due to improved crack-bridging behavior and fiber reinforcement. However, higher TFA contents (20–30%) substantially reduced workability and mechanical properties because of poor compaction and weak interfacial bonding. At 30% TFA, slump decreased by 48%, while compressive, tensile, and flexural strengths decreased by 58%, 31%, and 17%, respectively. SEM, XRD, and FTIR analyses provided evidence of N–A–S–H and C–A–S–H gel formation, which may have contributed to enhanced matrix integrity and microstructural development. Overall, the combined use of waste glass powder and tire fiber aggregate demonstrates strong potential for developing sustainable geopolymer concrete, where low TFA contents improve tensile and flexural performance, while also causing a moderate reduction in compressive strength.
S. M. Osman, S. Hakim, A. Mhaya et al.· Discover Concrete and Cement· 0 citations
ABSTRACT This study investigates the fresh, mechanical, durability, and microstructural performance of self-compacting concrete (SCC) incorporating alkali-activated fly ash (FFA), glass powder (GGP), and their hybrid combinations with ordinary cement (OC). The aim is to evaluate the feasibility of sustainable SCC systems under low-molarity NaOH activation (1 M) while maintaining structural performance requirements. Results show that hybrid SCC mixtures achieved slump flow values between 495–640 mm, with T50 times ranging from 0.8 to 3.6 s, indicating acceptable flowability and stability. The 50OC–50FFA mixture exhibited a compressive strength reduction of 10–18%, while the 50OC–50GGP system showed a higher reduction of 15–25% compared to conventional SCC (100OC). Chloride ion permeability increased by 35–50% in 100FFA, whereas hybrid systems showed improved resistance with intermediate charge values, maintaining structural durability requirements. Freeze–thaw testing revealed durability factors exceeding 100% retention for hybrid mixes, while 100FFA failed after approximately 75 cycles. SEM and FTIR analyses confirmed that FFA promotes a denser geopolymeric network, whereas GGP exhibits limited reactivity under low alkalinity, behaving primarily as a filler. The study demonstrates that hybrid SCC systems provide a balanced trade-off between sustainability and performance, while also highlighting the limitations of low-alkali fly ash activation. Overall, the findings support the development of environmentally efficient SCC systems with improved durability and acceptable mechanical properties.
K. Saravanan, Rajeshkumar Viswanathan, Bragadeeswaran Thangavel et al.· Matéria· 0 citations
Cement-stabilized soil is widely used for ground improvement but suffers from brittleness and low tensile strength. This study investigates combined modification of cement-stabilized soil with waste brick powder (WBP, 5%) and glass fiber (GF, 0–2.0%) to enhance mechanical performance and microstructural integrity. Unconfined compressive strength (UCS), splitting tensile strength (STS), and qualitative scanning electron microscopy were evaluated at 3, 14, and 28 days. Results reveal stress-state-dependent reinforcement: UCS peaked at 2.0% GF with gains of 18.1%, 7.3%, and 9.1%, while STS maximized at 1.5% GF (43% increase), declining 14.3% at 2.0% due to fiber agglomeration. Post-peak ductility improved markedly, with the residual strength ratio increasing from 12.4% to 43.2% and the ductility index from 1.18 to 1.85. Microstructural analysis suggests that uniform fiber dispersion enables crack bridging and interfacial load transfer, whereas agglomeration creates localized weak zones. Preliminary assessment indicates that WBP substitution may avoid approximately 85 kg CO2eq per cubic meter by valorizing construction waste. These preliminary laboratory findings suggest potential stress-state-dependent dosage trends for sustainable cement-stabilized soil composites, pending further validation.
Xiaosan Yin, Md Mashiur Rahman, Jian Wang et al.· Materials· 0 citations
The replacement of conventional aggregates in concrete with alternative and waste-based materials has become an important research area for sustainable construction. This study experimentally investigated the effects of natural perlite aggregate replacement and fiber reinforcement on the mechanical and microstructural properties of concrete. Natural perlite aggregate was used to replace conventional crushed stone aggregate at replacement levels of 0%, 30%, 70%, and 100%, while hemp shives, recycled plastic waste fibers, and polypropylene (PP) fibers were incorporated at volume fractions of 0.0%, 0.5%, 1.0%, and 1.5%. After 28 days of curing, compressive strength, modulus of elasticity, flexural strength, splitting tensile strength, ultrasonic pulse velocity (UPV), compressive stress–strain behavior, and scanning electron microscopy (SEM) analyses were performed. The results showed that 30% perlite replacement increased the compressive strength and modulus of elasticity by approximately 6.67% and 4.08%, respectively, compared with the reference mixture. In contrast, replacement levels of 70% and 100% reduced the mechanical performance due to the porous structure of perlite and the weaker interfacial transition zone. Among the fiber-reinforced mixtures, the optimum fiber content was found to be 1.0%, while PP fibers provided the best overall performance in terms of crack-bridging ability and energy absorption. Overall, the combination of 30% natural perlite aggregate replacement and 1.0% PP fiber was identified as an effective approach for producing low-carbon concrete with balanced mechanical properties.
Recycled aggregate concrete (RAC) offers an effective approach to reducing the environmental burden associated with construction and demolition waste. In this study, a fiber-reinforced RAC was developed by replacing part of the cement with fly ash and ground granulated blast-furnace slag, while glass fibers or basalt fibers were incorporated as reinforcing materials. A systematic experimental program was conducted to evaluate the mechanical behavior of the proposed concrete under different saturation conditions. The results show that the best toughness performance was achieved in the natural moisture state. In comparison, compressive and flexural strengths reached their maximum values under dry conditions, whereas splitting tensile strength peaked in the natural state. Based on the experimental data, prediction equations were established for the splitting tensile and flexural strengths by considering both saturation degree and fiber content. A stress–strain model under uniaxial compression was also developed. In addition, scanning electron microscopy (SEM) was employed to examine the fiber–matrix interface and hydration products, thereby clarifying the microstructural characteristics of the concrete at different saturation levels.
Jie Zhou, Tengfei Guo, Xiang Li et al.· Buildings· 0 citations
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