Strength and Durability Properties of Self Compacting Concrete Incorporating Rice Husk Ash and Metakaolin

Abstract

This study is about design and development of self-compacting concrete (SCC) using supplementary cement materials (SCMs). These SCMs has wide applications in concrete which contribute in enhancement of strength and durability. In this study, two types of SCMs have been used; Metakaolin (MK) and Rice Husk Ash (RHA). MK is a SCM which results from the heating of kaolinite clay in span of specified temperature, while RHA is a by-product obtained from the paddy fields. Rice husk when burnt in range of specified temperatures it results in RHA. To carry out the investigations,firstly, a control mix (M1), without any of the SCM (MK and RHA) was designed. Then, three mixes (M2, M3, M4) were prepared with partial replacement of cement with MK in proportions of 5, 10 and 15%. Three other mixes (M5, M6, M7) were made with the partial replacement of fine aggregates with RHA in the varying proportions of 10, 20 and 30%. Then, on the basis of 28 day compressive strength, ten additional mixes (M8 M16), with combination of both (MK and RHA) were made. In mixes M8 M10, MK content was kept constant at 5% and RHA content was varied between 10 to 30%. Similarly, in mixes M11 M13 and mixes M14 M16 MK content was kept constant at 10% and 15% respectively, and RHA content was varied between 10 to 30%, similar to mixes M8 M10. Mixes made with MK and RHA were tested for fresh properties, strength properties (compressive strength and splitting tensile strength), durability properties (water absorption, sulphate resistance, RCPT) and micro-structural properties (SEM and XRD) up to age of 365 days. Statical analysis of the results was also undertaken. All the mixes fulfilled the EFNARC criteria for the fresh properties. Use of MK and RHA increased the water demand but that can be managed by increasing the slight dose of super-plasticizer. The inclusion of MK and RHA positively affected the compressive strength at all ages. Mix M11 (10MK10RHA) showed the highest strength upgradation.