Study on the optimum mixing condition for control of spalling in high strength concrete by a orthogonal array

摘要

This study proceeded to find the optimum mixing rate of a high strength concrete with 80MPa of compressive strength using meta-kaolin, waste tire chips, polypropylene, and steel fiber together for improvement of fire resistance performance. To estimate of optimum mixing rate, the orthogonal array method was used to plan the factors (slump flow, air content, compressive and flexural strength, steel bar temperature and concrete spalling volume) of high strength concretes and experiment was executed. Then the functional relationship of each factor was valuated by general linear model of ANOVA and functional relation between the factors and the data was estimated using response surface analysis. The optimum mixing rate was computed as 80% replacement of silica fume volume by meta-kaolin, 3% replacement of fine aggregates volume by waste tire chips and 0.2% additive rate of polypropylene fiber without steel fiber to the total mixed volume with this modeling of the functional relationship.