AUTOGENOUS SHRINKAGE OF LIGHTWEIGHT AGGREGATE CONCRETE AT EARLY AGE

The deformation of concrete specimen was monitored at 3 hours later after casting by using the autogenous shrinkage testing device developed by ourselves. And the effect of lightweight aggregate with different degree of water saturation on early age autogenous shrinkage of lightweight aggregate concrete with different water-binder ratios were investigated, and compared with that of common aggregate concrete. The results indicates that the autogenous shrinkage of concrete incorporated with pre-soaked lightweight aggregate is significantly lower than common concrete, and the autogenous shrinkage of lightweight aggregate concrete decrease with the increase of the water content in aggregate. The ratio of water to binder has a significant effect on early age autogenous shrinkage. The autogenous shrinkage of lightweight aggregate concrete with water-binder ratio of 0.6 is just about 30% of the concrete with water-binder ratio of 0.3. By monitoring the temperature evolution of the concrete, it was found that the rise of temperature induced by the heat of hydration was as much as 5.1 degrees C. And the temperature deformation due to cement hydration has a great influence on the testing results of autogenous shrinkage of concrete.