DURABILITY STUDIES ON M30 GRADE CONCRETE CONTAINING QUARRY SAND AND FLY ASH

The durability of concrete is defined as its ability to withstand weathering action, chemical action, chemical attack or any progressive deterioration. A durable concrete requires little or no maintenance and retains its original form, quality and serviceability when exposed to harsh or aggressive environments. In view of depleting natural resources, quarry sand is recommended as potential substitute for river sand. Source governs the performance of quarry sand in concrete. There is urgent need to investigate durability performance of concrete containing quarry sand available. In this research attempt is made to examine the suitability of replacing cement by fly ash and natural sand by with various percentage of quarry sand for M30 grade concrete. Mix design was carried out and three combinations were chosen, first combination using 100% Natural sand and 100% cement (treated as controlled mix), in second combination 100%Natural sand is replaced by Quarry sand and cement remains100% and in third combination 30% cement is replaced by Fly ash and 45% Natural sand is replaced by Quarry sand (treated as critical mix). Comparison of performances of concretes in relevance to durability is presented in the paper. It is observed that 100% replacement of natural sand with quarry sand is not justifiable from durability point of view, especially in relevance to permeable voids formation, RCPT and acid attack; the use of fly ash significantly enhances durability properties of concrete. It is recommended that whenever it is imperative to use quarry sand in concrete, adequate quantity of fly ash must be added as partial replacement of cement to enhance durability of concrete.