Investigating the Use of Chert Powder as a Partial Replacement of Cement in Concrete

Abstract

The study aimed to study the feasibility of incorporating chert powder as a partial replacement of cement in concrete to enhance durability by mitigating sulphate attacks. The findings however demonstrated that chert powder functions effectively as a natural pozzolan with 94.7% silicon dioxide, exhibiting a chemical composition of 59.7% above the required minimum of 35%. Also, a total chemical composition for its main oxides was recorded at 97.65% surpassing the threshold of 70% stipulated for natural pozzolans as per the X-Ray Florescence (XRF) tests. Additionally, an analysis of the chemical properties of fresh concrete at varying replacements off chert powder revealed 8.75% increment in the concrete’s workability with an optimum slump of 86mm at 10% CP after 28 days, ensuring a workable concrete matrix within the acceptable design slump ranges of 25-100mm. Furthermore, the compressive strength loss of concrete decreased by 7.48% after 28 days from 13.65% off the neat mix when cement was partially replaced with CP at 10%, making it suitable for achieving C40 concrete that is resistant to sulphate attacks basing on the BS EN 12390-3:2002 test methods.