FUNDAMENTAL PROPERTIES OF AMBIENT-TEMPERATURE-CURED ULTRA-HIGH-STRENGTH FIBER-REINFORCED CONCRETE

Abstract

This paper is about fundamental properties of ultra-high-strength fiber-reinforced concrete (UFC) that does not need steam curing. The compressive strength of ordinary UFC is over than 150 N/mm 2 , and it has high toughness and durability. Most UFC needs steam curing at high temperature and for long time to achieve stable performance, and the energy required for steam curing results in high cost of manufacturing. UFC is usually manufactured in concrete products factories and transported to construction sites. This leads to improved product quality and concrete stability, but increases constructing costs. In this study, new type of UFC that can be produced by curing at ambient temperature has developed. The main materials used are ordinary Portland cement, fine blast-furnace slag powder, silica fume and so on. In this paper, it is examined the effects of cement types, blending ratio of powders, and Blaine specific surface area of blast-furnace slag powder on fresh and hardened characteristics of UFC. Based on the results, it is found that UFC using ordinary Portland cement as the main powder shows superior fluidity, lowering requirements for air entraining and high-range water reducing agents. And without steam curing, the developed UFC achieves compressive strength exceeding 150 N/mm 2 and bending strength exceeding 40 N/mm 2 by curing at ambient temperature (20 °C). The developed UFC can be produced in constructing site, therefor it can reduce construction costs comparing to ordinary UFC.