Influence of heat curing on the pore structure and compressive strength of self-compacting concrete (SCC)

The mechanical properties of self-compacting concrete (SCC) are well understood. But there are no scientific investigations available on the influence of a heat treatment on the properties of SCC. To evaluate the influence on the compressive strength, SCCs as powder type, combination type and viscosity-agent type in the strength classes between C20/25 and C70/85 were designed and exposed to heat treatment with different maximum temperatures. It has been found that there is an influence of the composition of the concrete, especially the (w/c)eq ratio, on the compressive strength after heat treatment. The reason for the substantial loss of strength in some cases compared to the strength of the concrete, which was stored under standard conditions, is a change of the pore size distribution. An empirical formula is presented to calculate the influence of the heat treatment on the compressive strength of the SCCs.