ABSTRACT STUDIES ON THE M20 GRADE CONCRETE WITH PARTIAL REPLACEMENT OF FINE AGGREGATE TO COIR PITH For construction purpose the largest consumer is concrete. The demand for concrete has been increased by day by day over the last years and it continues to do so. Fine aggregate (sand) play a major role in concrete as the demand of concrete increases the use of fine aggregate also increases which leads to the depletion of river sand. The extreme use of river sand for construction has many undesirable, and cause environmental and social consequences. We are looking for the alternatives of the river sand, due to the increase in the construction. We are proposed for partial replacement of sand (fine aggregate) with coir pith in varying proportions for M20 grade concrete and comparing its strength characteristics with of normal concrete.