Analyzing compressive strength of sustainable concrete with recycled refractory brick fine aggregate: an experimental and ANN approach

Purpose The growing trend of infrastructure development leads to the depletion of natural resources. Researchers are continually seeking suitable substitutes to mitigate the depletion of natural resources and conserve them. In view of this, this study aims to develop a few innovative concrete mixes with recycled refractory brick (RRB), which is a key by-product from different steel, refractory and other ancillary industries, as a partial to total replacement for fine aggregate. Design/methodology/approach In this investigation, M25-grade concrete with two different types of design mix ratios with 1:1.98:3.78 and 1:2.17:3.74 were produced with a w/c ratio of 0.45. The RRB has been used as a substitute for fine aggregate by weight at 00%, 10%, 20%, 30%, 40%, 50%, 70% and 100% levels. The compressive strength of different concrete mixes has been evaluated after 7 and 28 days of curing periods with potable water having an approximate temperature of 23 ± 2°C. Particle size gradation (mm), fineness modulus, consistency (%), specific gravity and water absorption (%) tests for the raw materials and compression test after 7 and 28 days for the concrete specimens have been conducted. Moreover, the experimental outcomes have also been confirmed through an artificial neural network (ANN). Findings Experimental investigation reveals that, after a seven-day curing period, the sample with 40% and 50% RRB, and after 28 days, samples with 20% replacement of RRB yielded the highest compressive strength, which are 33%, 39% and 15%, respectively. Based on the microstructural analysis, it has been evident that the development of CH and CSH gels fills up the micro pores and results in an improvement in compressive strength. Similar to the experimental output, the proposed ANN model confirmed similar output with the least error percentage of ± 2%–4%. Originality/value The residual mechanical strength and potential of RRB incorporated concrete may be considered appropriate for a wide range of applications under harsh climatic conditions, in particular under high temperature gradients. Deployed ANN to offer specific evaluations of compressive strength short of relying on traditional models, considering complex relationships. The sustainable concrete with recycled refractory brick fine aggregate suits eco-friendly construction, structural and/or nonstructural uses in compliance with IS 10262, IS 516, IS 456. The ANN model complements IS design, accurately predicting strength and optimizing mixes for sustainable construction practices.