P. Gowthami, B. Sudheer Kumar, B. Sravan Teja
Abstract: Now a day's using sand as a fine aggregate is becoming over exploiting due to heavy constructions. Due to this scarcity of sand occurs for the future generation. The concrete industries are facing the environmental impact of the cement production by the emission of carbon dioxide. Partial replacement of cement has been tried by low, medium and high volume with pozzolanic waste materials that include fly ash, silica fume, furnace slag having high silica and cementitious contents. Among all the replacement materials for cement, fly ash has been identified which is being produced in large quantities comparatively is recommended for use in concrete.  Most of them are confined to the utilisation of low calcium fly ash called class F fly ash, which is the waste, based on coal burning in thermal power stations. The production of cement poses environmental problems due to emission of gaseous pollutants, because the production of one ton of Portland cement emits approximately 1.0 tons of CO2 into the atmosphere.
In the specification for concrete the grade of concrete quantity of cement to be used, aggregate quantities, consolidation are being mentioned now a days. [2,5]The depletion of natural materials for manufacture of cement and the drawbacks of OPC demand for a durable concrete. The day is not far away then the people demand for a concrete with specifications for mentioning the standards of Chloride permeability/resistance, Water permeability, Acid resistance, Alkaline, Sulphate resistance etc. To make concrete economical, there is a need to use the supplementary materials for imparting Strength and durability to cement/concrete. In order to reduce the environmental problem that are caused by the large scale production of OPC, there is a direct need to use supplementary cementing materials, which are locally available. [3,8,9]In the present study, Stone Powder Dust ,which is rich in Calcium is used along with Nano Fly Ash to replace partially the cement in M30 grade concrete and an attempt is made to study the durability properties namely acid resistance, Chloride permeability and Water permeability. The OPC is replaced by stone powder dust from 5 to 15% and Fly Ash from 20 to 40% separately and the combination of these two materials.
Keywords: Fly ash, stone powder dust, compressive strength, Rapid Chloride permeability, Acid attack, and Water permeability