Mechanical and durable properties of chopped basalt fiber reinforced recycled aggregate concrete and the mathematical modeling

Herein, the study conducts an experimental research on the mechanical strength and durability of chopped basalt fiber (BF) reinforced recycled aggregate (RA) concrete. BF at six volumetric dosages of 0, 0.25, 0.5, 0.75, 1 and 1.5% and RA at five volumetric substitution levels of 0, 25, 50, 75 and 100% are used in determining the compressive strength, the splitting tensile strength, the specific strength [ratio of splitting tensile strength and apparent density] and the chloride penetration. Results show that BF reinforces both RA and nature aggregate (NA) concrete in a dosage dependent way. Relative to the late strength, BF has a better reinforcement effect on the early strength of RA concrete. BF content though is positively related to the splitting tensile strength is with a declined marginal utility. The opitmal dosage thereby exists and is identifed as 1%. Given the reinforcement of BF and the lower density of RA, the combined use of BF at low dosage and RA in high content results in a specific strength that is higher than that of RA concrete. Besides the strength enhancement effect, BF also descends the porosity and ascends the resistance to chloride penetration of RA concrete. The respond surface methodology interestingly is found to have a prominent role in establishing a mathematical model between the compressive and the splitting tensile strength because both strengths have respond surfaces that are shaped by BF and RA. Aforementioned results verify inferior properties of RA concrete can be offset by BF addition, signifying a complementary effect between BF and RA. (c) 2021 Elsevier Ltd. All rights reserved.

Automated summary

The study demonstrated that adding chopped basalt fiber (BF) can enhance the mechanical strength and durability of recycled aggregate (RA) concrete, showing a complementary effect between BF and RA. BF at an optimal dosage of 1% has the best reinforcement effect on RA concrete, while also reducing porosity and increasing resistance to chloride penetration.