Effect of Heat Curing in Core and Surface of Massive Concrete Structures on long term Strength of High Strength Concrete

The properties of the surface and the core, due to the hydration heat development, are normally different in mass concrete. In the present paper, hydration heat regime was applied on a cabinet contain specimens, with 0.3 water/cement ratio, to examine the influence of heat development on strength properties.Natural pozzolan, fly ash and silica fume were used, as partial replacement for cement in the predetermined specimens. The samples were taken after 1, 2 and 5 days from cabinet, to simulate surface and core of mass concrete, and then were cured in special conditions. The results indicated that strength of the natural pozzolan and fly ash samples, which were taken after 2 days from heat cabinet, attained maximum strength. While, strength of the silica fume specimens promoted when 1-day remolding time was used. Furthermore, silica fume adversely diminished compressive strength of the core specimens.