大粒径堆石混凝土超声回弹综合测强曲线的试验研究

Experimental Research on the Strength Test Curve of Large-sized Rock filled Concrete by the Ultrasonic-rebound Combined Method

堆石混凝土因骨料粒径大而无法通过常规力学试验得到其抗压强度,超声回弹综合法具有无损、迅速、准确方便等特点,但堆石混凝土中大粒径块石与自密实混凝土材料界限分明,会影响超声的传播及回弹值的代表性,研究了用超声回弹综合法进行堆石混凝土抗压强度检测的可行性。利用超声波检测仪和混凝土回弹仪,对堆石混凝土大试块进行抗压强度检测试验,试验结果表明,超声值、回弹值与实测抗压强度均呈正相关关系,相对而言,回弹值的相关性更好;普通混凝土全国统一测强曲线不适用于检测堆石混凝土抗压强度;用超声回弹综合法检测堆石混凝土的抗压强度是可行的。

Due to the large aggregate size,the compressive strength of rock filled concrete cannot be obtained by conventional mechanical tests.The ultrasonic-rebound combined method has the characteristics of nondestructive,rapid,accurate and convenient,but the large-sized particles in rock filled concrete has clear boundaries with self-compacting concrete material,which will affect the ultrasonic propagation and the representative rebound value.The feasibility of testing the compressive strength of rock filled concrete with the ultrasonic-rebound combined method is studied.The ultrasonic testing instrument and concrete rebound instrument are used to test the compressive strength of large rock-filled concrete blocks.The test results show that,(a)the ultrasonic value and rebound value have a high degree of interpretation to the measured compressive strength,and relatively,the rebound value has a better correlation;(b)the national unified strength measurement curve of ordinary concrete is not applicable to the testing of the compressive strength of rock-filled concrete;and(c)it is feasible to test the compressive strength of rock filled concrete with ultrasonic rebound combined method.