Establishment of minimum fine aggregate proportion is the first step in the process of selecting aggregate proportions for the self-compacting concrete. To this end different fine aggregate proportions were tested under a constant doze of viscosity modifiers to find the minimum proportion of fine aggregate required to make SSC. U Box was used as the preferred mode to test the conformity of the self-compacting concrete.
Once conformity is ensured by U box the mixes were checked for segregation resistance using the funnel test and filling capacity based on the slump flow test. With offshore sand as fine aggregate, it is found that 50% of offshore sand by total aggregate weight is the minimum fine aggregate percentage for making self-compacted concrete. This percentage is found to be 55% for river sand and 60% for the quarry dust.
All these results were obtained for Glenium C320 doze of 1500 ml per 100kg of cement. With this initial results of minimum percentage of fine aggregate required under different aggregate types, common fine aggregate proportions to total aggregate proportions of 60%, 70% and 80% was considered to study the influence of fine aggregate type on the properties of self-compacting concrete. As self-compacting concrete requires only conformity to the workability requirement specified in the table 1, mixes with
different workability ceases to become a variable for studying the SCC. This makes aggregate type, fine aggregate proportion to total aggregate, and the w/c ratio the only variables for the study. Fig.6 show the different mixes studied for determining the influence of fine aggregate types on the properties of SCC. To make mixes with different aggregate and mixes of same aggregate with different w/c ratio comparable to each other same doze of viscosity modifier, 1500 ml for 100kg of cement is used for all mixes. In order to achieve the desirable workability under the constant doze of viscosity modifier water content was adjusted. The results of different water quantities required to achieve the required fluidity are then used as an indicator for the performance of different aggregate types.