Early strength development in concrete using preformed CSH nano crystals

Abstract

The pace of production of pre-cast elements are dependent on the formwork removal time and are governed by early strength gain process of concrete. Conventionally, the production cycle is enhanced either by adopting elevated temperature curing or by the use of commercially available hardening accelerators which often cause durability related problems in concrete. In this work, an attempt has been made to use preformed CSH nano-crystals synthesized from agricultural waste material for early strength development in concrete. Inclusion of such seeding material in concrete can effectively eliminate the nucleation period in the hydration process and can accelerate the early strength development without compromising in the ultimate strength and durability properties. The effectiveness of these preformed CSH seeds on the early age strength gain process has been verified and confirmed by measuring setting time, compressive strength, heat of hydration and by performing X-ray diffraction and thermal analysis. With the addition of CSH seeds, relatively faster precipitation of hydration products and early strength development have been observed.