Use of tabletting & coating accelerator for the prevention of early-frost of concrete in cold weather

The use of accelerators prevents early-frost by developing strength of concrete in cold weather. However, no security of workability occurs because early hydration makes them to react rapidly. Thus, the accelerators via tabletting were coated with polyvinyl alcohol (PVA) of water-soluble polymer substance. The discussion includes the following: mortar setting time, workability by elapsed time, early strength to assure the development of adequate strength, and freezing–thawing resistance. As a result, workability can be secured as well as the development of early strength to prevent early-frost. The porosity and progress of hydration affecting the concrete were also found to be superior by analyzing the mercury intrusion porosimetry (MIP) and scanning electron microscopy (SEM) results.

► Accelerators via tabletting were coated with polyvinyl alcohol (PVA).
► PVA, which has good stiffness, is water soluble and can be adjusted.
► PVA coating tablets satisfied workability and strength for prevention of early-frost.
► PVA coating tablets can resist frost damage under repeated freezing and thawing.
► After PVA coating tablets react, the pore structure of concrete was not affected.