Determining an Efficient Approach for Compound Curing of High Resistant Concretes under Saturated / Autoclave Medium and Studying the Influence of Saturated Situation on Reduction of Holdinng Time in Autoclave

In order to determine an efficient approach for compound curing of high resistant concertes under saturated/ autoclave medium and studying the influence of saturated situation on reduction of holding time in autoclave, the research was carried out using different curing methods. Concrete specimens which were prepared on standard methods were divided into control and treated ones from which the formers were just exposed to saturated situation(which attained compressive strength of 884.54 Kg/cm2 at 28 days) while the other 3 sets were cured as follows: First and second part were placed under saturated situation for one to three days but the remaining one) was directly transferred to autoclave. All of these 3 sets were maintained in autoclave for 15 to 150 minutes. Results showed that specimens kept in autoclave for 15 minutes (without any maintenance at saturated situation), attained compressive strength of 748.73 Kg/cm2 while in the case of the ones kept at saturated situation for one-day (before autoclave) the compressive strength to 834.71 Kg/cm2 which was about 84.65 and 94.37% of compressive strength of the control sample at the age of 28-days respectively. By increasing the autoclave time to 30 minutes, the compressive strength of the specimens under two circumstances mentioned above improved up to 892.40 Kg/cm2 and 903.51 Kg/cm2 respectively which was about the compressive strength of the check specimen in 28 days. We found no impact on compressive strength growth whenever samples were kept in autoclave for more then one-day