Enhancing High Early Concrete With Mineral Additive

high early concrete is a type of concrete that attains a high compressive strength at an early age. This type of concrete is used for fast-track paving, precast elements, and cold weather construction where it facilitates rapid pace of construction.

It is achieved by using one or combination of type III Portland cement, high cement content, low water to cementitious materials, high freshly mixed concrete, chemical admixtures, supplementary cementitious materials, autoclave curing, and insulation of concrete to retain its heat of hydration.

The process of enhancing the early strength of concrete can be achieved through the application of accelerated chemical admixture. Advised levels of a variety of chemical admixtures, including calcium nitrate, fibers, non-chloride hardening accelerators, and colored concrete washout can be added to the mix composition.

This study investigated the effect of the addition of a low calcium silicate based mineral additive, alccofine 1203 (Alccofine), on the tensile properties and durability of high early concrete mixes made with varying water to cement ratios and concentrations of the calcium nitrate as a non-chloride hardening accelerator (NCHA). The results showed that alccofine increased the tensile strengths at 1 and 7 days for water binder ratio 0.45.

The study also demonstrated that the accelerated effect of alccofine was significantly decreased after 24 hours. However, alccofine enhanced the hydration process in the initial hours of curing. The early strength of alccofine concrete, with its higher hydration degree and increased pozzolanic reactivity, was comparable to the reference concrete.