Ultrafine Cement Research Articles

The strength and deformation characteristics of high early strength structural concrete

There are many possible structural applications of concrete with a compressive strength of about 100 N/mm2. In practice, however, the development of early strength is far more important, but the combination of both can bring considerable economic benefits to the construction industry. Tests are reported on the strength and deformation characteristics of high early strength structural concrete. Tests using an ultra fine cement with expanded slate lightweight aggregate and granite produced concretes with a strength of 30–40 N/mm2 and 60–70 N/mm2 respectively in 24 hours. Tests with aluminous cement produced better aggregate-matrix bond and developed strengths of about 95 N/mm2 in the same time. Equations are presented to predict the tensile strength and elasticity of the high early strength concrete. It is shown that the rapid hydration results in a high rate of shrinkage and creep initially but the long-term deformation characteristics are comparable to normal concrete. It is suggested that it is worth exploring methods to minimise the effects of conversion.