Title: Dry-mix/Steam-Injection Method for Producing High-Strength Concrete in One Day

Author(s): T. D. Lin

Publication: Symposium Paper

Volume: 149

Issue:

Appears on pages(s): 665-678

Keywords: clinker; high-strength concretes; hydration; mix proportioning; mortars (material); strength; temperature; water-cement ratio; Materials Research

DOI: 10.14359/4117

Date: 10/1/1994

Abstract:
Cement particles generally consist of micropores measuring 5 to several hundred. The micropores are too small to permit permeation of water due to water surface tension, but large enough to accommodate diffusion of steam under elevated pressure. The size of a water molecule has been scientifically determined. When dry cement particles are in contact with steam, heat immediately transfers from steam to cement, and part of the steam is forced into inner regions of the cement particles via the micropores. As a result, cement particles gain activation energy, and at the same time steam partially condenses due to energy dissipation to form moisture coating on the surfaces of cement particles as well as the interior surfaces of the micropores. Both the activation energy and condensation of steam enhance a rapid and complete hydration. Test results show that concrete made with the dry-mix/steam-injection procedure developed high CSH/CH ratios in paste and a high strength of 700 kgf/cm 2 (10,000 psi), approximately 2.5 times that of companion concrete made with the wet-mix procedure, in less than 1 day. Another test series demonstrated a 50 percent reduction of cement requirement in comparison with the wet-mixed concrete with an equivalent strength of 560 to 630 kgf/cm 2 (8000 to 9000 psi).