基于纤维水泥砂浆加固的后装拔出试验

为利用后装拔出法检测纤维水泥砂浆抗压强度,模拟工程加固情况:分别采用合成纤维(聚丙烯纤维、聚乙烯醇纤维)水泥砂浆、钢纤维水泥砂浆对素混凝土试块进行加固处理。加固后,对加固薄层进行后装拔出试验,获得拔出力。依据拔出力代表值和纤维水泥砂浆立方体抗压强度代表值之间的关系,采用离散最小二乘逼近方法拟合测强公式。结果表明:测强公式精确度比较高,测强公式检验效果良好、符合实际意义,其中钢纤维的掺入对增加拔出力的作用要高于合成纤维。依据测强公式,后装拔出法可以现场检测推定20~90 MPa的纤维水泥砂浆抗压强度。

Post-install pullout test based on fiber cement mortar reinforcement

In order to use the post-install pullout method to test the compressive strength of fiber cement mortar and simulate the status of reinforcement, synthetic fiber (polypropylene fiber and polyvinyl alcohol fiber) cement mortar and steel fiber cement mortar were used to reinforce plain concrete blocks, respectively. After the reinforcement, post-install pullout testing of the reinforced layer was carried out to obtain the pullout force. Based on the relationship between the representative value of the pullout force and the representative value of the corresponding compressive strength of fiber cement mortar test cubes, a fitting strength measurement formula was established using the discrete least squares approximation method. Results show that the accuracy of the strength measurement formula was high and the effectiveness of the strength measurement formula was validated in practice. The incorporation of steel fiber has a better effect on the increase of the pullout force than the synthetic fiber. According to the strength measurement formula, the post-install pullout method can test the fiber cement mortar on-site when the compressive strength ranges from 20 to 90 MPa.