PSI - Issue 71

Yash Rathore et al. / Procedia Structural Integrity 71 (2025) 401–408

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also meets BIS: 383-2016 standards, with a maximum particle size of 20 mm and a specific gravity of 2.79.

Fig.1. SCMs and M-sand used (a) MK; (b) RHA; (c) Crushed Deccan basalt M-sand. Fig.2(b) provides particle size distribution curves for both fine and coarse aggregates, illustrating their size distribution characteristics. The gradation curves for river sand (RS), manufactured sand (M-sand), and coarse aggregate were evaluated using sieve analysis as per IS: 383-2016. A set of sieves with varying sizes was used to classify the particle distribution of each aggregate type. The cumulative percentage passing through each sieve was recorded and plotted on a semi-logarithmic graph, with particle size on the x-axis and percentage passing on the y-axis, to effectively illustrate the gradation characteristics. The analysis revealed that the fine aggregates (RS and M-sand) fall within a specific Zone as per IS: 383-2016, ensuring their suitability for concrete applications. Similarly, the coarse aggregates comply with the standard size range prescribed in IS: 383-2016. A polycarboxylic ether-based superplasticizer (SP) with a specific gravity of 1.08 is added to the concrete mix to improve workability.

Fig.2. Particle size distribution curve (a) Binding materials; (b) Aggregates.

3. Experimental Methodology This study aims to assess the mechanical properties and acid resistance of concrete that incorporates MK, RHA, and Deccan basalt M-sand as supplementary materials. The concrete mix designs were developed following IS 10262-2019 guidelines for M40 grade concrete, with a target slump of 75-100 mm. Various test specimens were prepared, including 150 mm cubes and 150 × 150 × 700 mm beams. Compression and flexural strength tests were conducted according to IS 516-1959 standards, with three specimens used for each test and average results reported. The initial phase of the study focused on replacing OPC with RHA at levels of 0%, 5%, 10%, 15%, 20%, and 25% by weight as detailed in Table 1. The mechanical strength of these mixes was evaluated to determine the optimal RHA content as shown in Table 1. Results showed that a 20% RHA replacement (R20) yielded the highest mechanical strength (Table 1). Building on

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