Permeability of Corncob Ash, Anthill soils and Rice husk replaced concrete

Durability of concrete is defined as its ability to resist any form of deterioration, allowing it to retain its original form and quality after exposure to the environment of its intended use. Permeability is the most important aspect of durability and service lives of concrete structures, and is measured by the ease with which a gas or liquid can get into and pass through concrete, or rate at which water under pressure can flow through interconnected voids within concrete. It has been suggested that pozzolanic reactions from Supplementary Cementitious Materials (SCMs) help in filling up pores using the Calcium Silicate Hydrate (C-S-H) gel that is formed during the secondary hydration of cement, through the reaction of calcium hydrixide [Ca(OH)2] with silicon dioxide (SiO2), which densifies the pore structure and transition zone, thereby reducing permeability from the packing effect of unreacted particles. This work investigated the water absorption performance of Corncob Ash (CCA), Anthill Soil (AHS) and Rice Husk Ash (RHA) concrete specimens. Tests were conducted on specimens that were found to have achieved the highest compressive strengths from strength tests and also on specimens that were made out of 30% (per cent) cement replacements. Results indicated that the water performance of all the three materials, including that of the ternary specimens of CCA and AHS were above those of the control specimens at highest compressive strength, and highlight the potential of using CCA, AHS and RHA at lower replacements to improve the durability of concrete.