Experimental investigation of Bambara nut shell ash in the production of concrete and mortar

The goal of producing concrete that provides long-term durability with regard to characteristics like strength and reduced susceptibility to alkali-silica has led to the development of several high-performance materials. While the use of Bambara nut shell ash in concrete is gaining acceptance in various applications, the mineralogical composition of such by-product materials cannot be easily controlled as a manufactured pozzolan. In this research work, the characterization and use of Bambara nut shell ash in concrete production were investigated. A mix proportion of 1:3:6 with water cement ratio of 0.55 were used. The percentage replacement of cement with Bambara nut shell ash (BNSA) is 0%, 5%, 10%, 20%, 30% and 40%. Concrete cubes of 150 mmx150 mmx150 mm of OPC/BNSA were cast and cured at 3, 7, 28, 60 and 90 days , respectively. At the end of each period of hydration, three replicate concrete samples for each period of hydration were crushed and their average comprehensive strength was recorded. The result for the compressive strength test indicated rise in percentage difference as the BNSA replacement ratio increases from 5 to 40% with a value of 20.69-46.53%, respectively. The concrete density response showed slight increment in percent difference with a value of 0.85-3.47% for BNSA replacement ratio of 5-40%, respectively. The Poisson ratio test results obtained indicate percentage difference increase as the BNSA ratio increases from 5 to 40% with a value of 5.17-11.14%, respectively. Furthermore, the Young's modulus of elasticity results obtained showed percentage difference rise from 9.4 to 14.17% as BNSA ratio increases from 10.81 to 29.412% and as BNSA replacement ratio increases from 5 to 40%, respectively. The results indicate satisfactory performance at 5% replacement.

Automated summary

This research investigated the characterization and use of Bambara nut shell ash in concrete production, with results showing satisfactory performance at 5% replacement but decreased performance in compressive strength, concrete density, and Poisson ratio as replacement ratio increased to 40%.