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Evaluation of Mechanical Performance of High Strength Recycled Aggregate Concrete Containing Nano Silica
Subject area: Science,Engineering and Technology · Area of research: Civil Engineering
DOI: 10.64388/IREV10I4-1723961
Abstract
Recycled aggregate concrete (RAC) offers a sustainable route for absorbing construction and demolition waste, but its comparatively weak and porous aggregate structure limits its use in high-strength structural applications. Nano-silica has been reported to narrow this performance gap through pore-filling and pozzolanic action, yet its combined effect with recycled coarse aggregate (RCA) on the mechanical behaviour of high-strength recycled aggregate concrete (HSRAC) has not been fully characterised across a wide range of mix proportions. This study evaluated the compressive strength, flexural strength, split tensile strength, and water absorption of HSRAC produced with recycled coarse aggregate replacement levels of 0–40% and nano-silica dosages of 0–20%, across water-cement ratios of 0.23–0.42. A total of 25 mix combinations, generated using a Taguchi L25 orthogonal array as an experimental design tool, were cast, cured, and tested at 7, 14 and 28 days for compressive strength and at 28 days for the remaining properties, following relevant British and European Standard test methods. Results showed that a combination of 10% nano-silica and 20% RCA at a water-cement ratio of 0.37 produced the highest 28-day compressive strength of 52.9 MPa, a 23.1% increase over the plain control mix, alongside the highest flexural strength of 4.16 MPa. Split tensile strength generally declined with increasing RCA and nano-silica content, falling by up to 19.9% relative to the control, while water absorption increased from a "Good" durability range (3.6–4.6%) in the control mixes to a "Fair" range (5.4–5.9%) at the highest replacement levels. The findings indicate that nano-silica can substantially recover the mechanical performance of RCA-based concrete for compressive and flexural loading, but its benefit is more limited for tensile and durability-related properties, particularly beyond 20% RCA replacement.
Keywords
recycled aggregate concrete; nano-silica; Taguchi; compressive strength
How to cite this paper
@article{1723961,
author = {Chilowe, Mark Dominic, Barisua Ebenezer Ngekpe},
title = {Evaluation of Mechanical Performance of High Strength Recycled Aggregate Concrete Containing Nano Silica},
journal = {Iconic Research And Engineering Journals},
year = {2026},
volume = {10},
number = {4},
pages = {3001-3010},
issn = {2456-8880},
url = {https://www.irejournals.com/formatedpaper/1723961.pdf},
abstract = {Recycled aggregate concrete (RAC) offers a sustainable route for absorbing construction and demolition waste, but its comparatively weak and porous aggregate structure limits its use in high-strength structural applications. Nano-silica has been reported to narrow this performance gap through pore-filling and pozzolanic action, yet its combined effect with recycled coarse aggregate (RCA) on the mechanical behaviour of high-strength recycled aggregate concrete (HSRAC) has not been fully characterised across a wide range of mix proportions. This study evaluated the compressive strength, flexural strength, split tensile strength, and water absorption of HSRAC produced with recycled coarse aggregate replacement levels of 0–40% and nano-silica dosages of 0–20%, across water-cement ratios of 0.23–0.42. A total of 25 mix combinations, generated using a Taguchi L25 orthogonal array as an experimental design tool, were cast, cured, and tested at 7, 14 and 28 days for compressive strength and at 28 days for the remaining properties, following relevant British and European Standard test methods. Results showed that a combination of 10% nano-silica and 20% RCA at a water-cement ratio of 0.37 produced the highest 28-day compressive strength of 52.9 MPa, a 23.1% increase over the plain control mix, alongside the highest flexural strength of 4.16 MPa. Split tensile strength generally declined with increasing RCA and nano-silica content, falling by up to 19.9% relative to the control, while water absorption increased from a "Good" durability range (3.6–4.6%) in the control mixes to a "Fair" range (5.4–5.9%) at the highest replacement levels. The findings indicate that nano-silica can substantially recover the mechanical performance of RCA-based concrete for compressive and flexural loading, but its benefit is more limited for tensile and durability-related properties, particularly beyond 20% RCA replacement.},
keywords = {recycled aggregate concrete; nano-silica; Taguchi; compressive strength},
month = {October},
doi = {https://doi.org/10.64388/IREV10I4-1723961}
}