Effects of Fiber Glass,Air Entraining Agent and Lightweight Aggregate on the Thermal Expansion Property of High Performance Concrete

• Main Authors: Jiang Mao-Li, 江茂利
• Other Authors: Chen Shun-Tyan
• Format: Others
• Language: zh-TW
• Published: 1998
• Online Access: http://ndltd.ncl.edu.tw/handle/45377223169879619520

碩士 === 國立臺灣科技大學 === 營建工程技術研究所 === 86 === High Performance Concrete (HPC) is a new construction material with high strength and high slump flow. However owing to its higher density, it also possesses higher thermal conductivity and is even easier to spall in fire temperature than ordinary concrete. In order to promote its engineering application, these negative fire-resistance characters need to be improved. This research tries to mix respectively the lightweight aggregate, fiber glass and air entraining agent in HPC and studies the effect of improvement of these mixtures on the fire-resistance behavior of HPC. The research project is divided into two parts : the first part studies the effect of the mixtures on the spalling and thermal expansion behavior of HPC；while the second part deals with the effect of the mixtures on the thermal conductivity and volumetric heat capacity of HPC. This report presents the research outcome of the first part. The parameters considered in this study are the strength of concrete , the amount of the lightweight aggregate, fiber glass and air entraining agent. A number of 10cm×10cm×30cm HPC specimens have been made and tested under a 3-dimensional heat load. The temperature rate was set to be 5℃/min in the tests and the maximum temperature was 800℃. The variations of the length of specimens were continuously investigated during the thermal load tests. After the tests，the residual thermal strains and the crack widths were measured. The test results indicate that adding fiber glass and air entraining agent in the HPC have the observable efficacy on avoiding spalling of HPC. However adding lightweight aggregate have no such efficacy . The HPC with increasing amount of fiber glass have smaller thermal strain and crack widths，while the ones with increasing amount of air entraining agent have also smaller crack widths but larger thermal strain. It is also found that the ranges in the variation of the thermal strain and the residual thermal strain of HPC at peck temperature are more pronounced than that of the normal strength concrete（NSC）. And the thermal expansion coefficient of the 8000psi HPC is close with that of the NSC，while the coefficient of the 10000psi HPC is smaller than that of the NSC.