Experimental evaluation of mitigation of autogenous shrinkage by means of a vertical dilatometer for concrete

High performance concrete, with low w/b-factors, can suffer from early age cracking due to autogenous shrinkage. This can lead to a relevant reduction of the service life of concrete structures. In order to study autogenous shrinkage of hardening concrete, a new dilatometer has been developed. Within this newly developed dilatometer, the fresh concrete is cast into a vertical Teflon tube. After compaction on a vibrating table, the concrete sample is placed into the measuring frame, inside a climate room. Linear vertical shrinkage measurements can start immediately after casting, by means of LVDT-transducers. Temperature measurements are realized in parallel, in order to take into account the effect of the heat of hydration on the autogenous shrinkage results. With this dilatometer, the mitigation of autogenous shrinkage by means of saturated lightweight aggregate particles and super absorbing polymers has been studied experimentally. The application of theoretical formulas, predicting the required content of internal curing water in order to compensate for the autogenous shrinkage has been evaluated. The application of saturated light-weight aggregates and super absorbing polymers proves to be a good technique in order to reduce autogenous shrinkage