纳米SiO_(2)对玄武岩纤维/混凝土高温后力学性能的影响

Influence of nano-SiO_(2)on mechanical properties of basalt fiber/concrete after heating at high temperatures

通过试验研究了普通混凝土(NC)、玄武岩纤维混凝土(BFRC)、掺纳米SiO_(2)的玄武岩纤维混凝土(NBFRC)在不同温度后的抗压强度、劈裂抗拉强度、抗折强度等力学性能。结果表明:在各个温度下,NBFRC的抗压强度、劈裂抗拉强度、抗折强度均高于BFRC与NC的强度。三种混凝土的抗压强度在400℃时达到最大值,随后逐渐降低,劈裂抗拉强度与抗折强度均随着温度的升高呈现下降的趋势。在常温下,NBFRC的抗压强度、劈裂抗拉强度、抗折强度较NC分别提高了13.2%、22.9%、13.2%;400℃时,较NC分别提高了12.4%、23.3%、21.9%;800℃时,三种混凝土的强度达到最低,此时NBFRC的抗压强度、劈裂抗拉强度、抗折强度仅为常温时的47.8%、29.1%、35.5%。依据试验结果建立的NC、BFRC、NBFRC的相对强度预测模型吻合度较高。

The high temperature mechanical properties of the normal concrete(NC), the basalt fiber reinforced concrete(BFRC)and nano-SiO_(2)basalt fiber reinforced concrete(NBFRC)were investigated, such as the compressive strength, splitting tensile strength, flexural strength, and so on. The results show that the compressive strength, splitting tensile strength and flexural strength of NBFRC are higher than those of BFRC and NC at each temperature. At 400 ℃, the compressive strength of the three kinds of concrete reaches the maximum, and then decreases gradually, and the splitting tensile strength and flexural strength decrease with the increase of temperature. Compared with NC, the compressive strength, splitting tensile strength, flexural strength of NBFRC increase by 13.2%, 22.9%, 13.2%, respectively, at room temperature, and by 12.4%, 23.3%, 21.9%, respectively, at 400 ℃. At 800 ℃, the strength of three kinds of concrete reaches the lowest, and the compressive strength, splitting tensile strength and flexural strength of the NBFRC are only 47.8%, 29.1% and 35.5% at room temperature. NC, BFRC and NBFRC relative strength prediction model is accurate.