Durability properties of self-compacting concrete (SCC) incorporating cassava peel ash (CPA)

Abstract

Self-compacting concrete (SCC) is a highly flowable concrete with enhanced strength and surface finish. The production of SCC requires high content of Portland cement (PC), which in turn consumes a lot of energy and emits greenhouse gases like CO₂ and CH₄ to the atmosphere during its production. Also, environmental pollution arising from agricultural wastes such as cassava peels, groundnut shells, is a cause of concern. Cassava processing centres alone generate approximately 40 million tons of wastes per annum in Nigeria, while attempts to eliminate them through burning or natural decomposition is sometimes unsuccessful. It is important to reduce the CO₂ emission during the production of PC and environmental pollution caused by cassava peels through partial replacement of cement in the SCC. This study assesses the durability properties of SCC produced with cassava peel ash (CPA) at 5 %, 10 %, 15 %, 20 % and 25 % replacement level of cement. The effects of water absorption, acid (H₂SO₄) and salt (MgSO₄) attack and elevated temperature were investigated on the CPA-SCC specimens. It was revealed that the CPA improves the resistance to H₂SO₄ and MgSO₄ degradation while the performance is poor when subjected to elevated temperature compared to the control specimen. Also, an optimum of 5% cement replacement is recommended for grade 35 compressive strength of CPA-SCC. However, the rate of water absorption reduced to a minimum when CPA is used in SCC as a result of an improved pore structure of the CPA-SCC specimen.