Investigating the Combined Effect of Cocoa-Pod Husk Ash and Discharged Engine Oil as Admixtures on Strength Properties of Concrete

Abstract

The demand for concrete in the construction industry continues to increase. This study examined the performance of concrete modified with discharged engine oil (DEO) and cocoa pod husk ash (CPHA) as admixtures, focusing on physical, mechanical, and durability properties, including density, water absorption, workability, compressive strength, splitting tensile strength, and abrasion resistance. The principal problem is not simply the availability of DEO and CPHA, but the lack of sufficient experimental evidence concerning their combined use as admixtures. This study was conducted at the AAMUSTED Construction Technology and Management Laboratory. CPHA was incorporated at 0%, 0.2%, 0.4%, 0.6%, 0.8%, and 1% by mass of cement, while DEO was added at a constant proportion of 0.066%, using a mix ratio of 1:2:4. The water-cement ratio was 0.55. Concrete specimens were cast and tested after 7, 14, 21, and 28 days of curing to evaluate workability, density, water absorption, compressive strength, splitting tensile strength, and abrasion resistance. At 28 days, the control concrete achieved a compressive strength of 31.08 N/mm², while the mix containing 0.20% CPHA and 0.066% DEO achieved 28.29 N/mm², the highest value among the CPHA replacement mixes. The corresponding splitting tensile strengths were 2.263 N/mm² for the control and 2.204 N/mm² for the 0.20% CPHA mix. At 28 days, the density of the 0.20% CPHA mix was 2414.00 kg/m³. Water absorption was 1.53% for the control and 1.23% for the 0.20% CPHA mix. For abrasion, the control recorded 0.93%, while the 0.20% CPHA mix recorded 1.32%. The study concluded that, although the control specimens generally produced the optimum results, concrete modified with 0.20% CPHA and 0.066% DEO showed the best performance among the CPHA replacement mixes and remained within the reported acceptable performance range for the investigated properties.