高温破坏时纤维增强混凝土的性能研究

对纤维增强高性能混凝土在高温下的力学特征和剥落趋势进行了试验研究．制备3种类型的混凝土：普通混凝土（NSC）和高性能混凝土（HPC1、HPC2）．高性能混凝土为分别在普通混凝土中加入5kg／m^3的聚丙烯纤维或40kg／m^3的钢纤维而制成．在龄期达到120d时加热试件，温度分别为100℃、300℃、500℃和700℃，然后冷却，测试其抗拉强度、抗压强度、弹性模量和超声脉冲速度．对比试验在室温20℃下进行．结果表明：NSC和HPCI的残余强度在500℃、700℃几乎为线性降低；而HPC2的残余强度在300℃则急剧降低，在两种HPC中，均发生了爆裂剥落现象．

Study on Property of Fiber Reinforced Concrete under High Temperature Damage

This paper carried out experimental study on mechanical characteristics and spalling trend of fiber reinforced concrete under high temperature damage. Three types of concrete were prepared： normal concrete （NSC） and high performance concrete （HPC1, HPC2）. The two types of high performance concrete were made of normal concrete respectively mixed with 5 kilogram polypropylene fiber or 40 kilogram steel fiber per cubic meter. Specimens were heated to the highest temperature of 100 ℃, 300 ℃and 500 ℃ at the age of 120 days and the tensile strength, compressive strength, elastic modulus and ultrasonic pulse speed were tested after being cooled. Contrast test was carried out at the room temperature of 20 ℃. The result shows that the residual strength of NSC and HPC1 at 500℃ and 700℃ exhibited a nearly linear decrease, while the residual strength of HPC2 at 300 ℃ decreased rapidly and bursting spalling occurred in both two kinds of HPC.