Experimental Investigation on Strength Properties of Concrete with Partial Replacement of Coarse Aggregate with Coconut Shell and Fine Aggregate with Basalt Powder and Rice Husk Ash as Mineral Admixture

Abstract

The investigation evaluates the use of coconut shell (CS), basalt powder (BP), and rice husk ash (RHA) as sustainable alternatives in M25 grade concrete to address the depletion of natural aggregates and environmental impacts of cement production. Eight concrete mixes were developed, including variations of CS, BP, and RHA replacements. Findings showed that while 10% CS replacement met the M25 strength requirements at 28 days, higher replacements reduced strength due to lower stiffness. BP at 10% enhanced compressive strength through improved particle packing, while RHA increasingly improved strength to a point, beyond which it decreased due to insufficient calcium hydroxide. The combination mix with 10% CS, 10% BP, and 10% RHA achieved the highest compressive strength, demonstrating synergistic benefits. The study recommends using these agricultural and industrial by-products for sustainable concrete construction without compromising performance.