มาตรวัดการกระแทกการประเมินคอนกรีตโดยใช้การทดสอบค้อนกระแทกแบบสมิดท์

Abstract

The Schmidt hammer is used for measuring the compressive strength of non-destructive concrete. However, the results obtained from the laboratory must be used together with the estimated values read from the hammer. This research therefore developed the impact measure to determine the compressive strength of concrete tested by Schmidt hammer. The concrete samples were made into 2 shapes which were cube with the dimension of 151515 cm3 and prism with the dimension of 306030 cm3. Each shape of samples were designed to achieve the strength at the range of 150 kg/cm², 180 kg/cm², 210 kg/cm² and 240 kg/cm² at 28 days then were tested using a Schmidt hammer together with a universal testing machine (UTM) test. The rebound number (RN) were in the range of 19-32. The regression between the compressive strength and the RN is the 3rd order polynomial function with the R² ranging from 0.9176 to 0.9766, indicating that the measure developed can be used effectively