Browsing by Author "Mohammad Hussain, Wail Asim"

Now showing 1 - 1 of 1
  • Thumbnail Image
    Item
    Estimation of compression strength of concrete with drillability test
    (Universiti Teknologi Malaysia, 2015) Mohammad Hussain, Wail Asim
    This research aims to establish a reliable equation to estimate the strength of in-situ concrete based on the drilling resistance measurements using a new designed non-destructive testing machine. This test includes three measured parameters: the drilling penetration rate, the pressure needed to drill a certain depth and the drilling rotational speed. Some previous studies used the same technique to determine the strength of other construction materials, such as rocks or marbles. However, none of the previous studies attempted to use the drilling penetration rate to estimate the strength of in situ concrete. The estimation of concrete strength using the drilling test measured parameters was expected to be more reliable than using the ordinary non-destructive tests to estimate the strength of concrete. In this study, a new drilling machine was designed by considering all the factors that can affect the estimation of concrete strength. In addition, the rebound hammer and the ultrasonic pulse velocity tests were used to estimate the concrete strength for comparison with the new technique. Ten different concrete batches were prepared with different mix proportions; each batch consisted of twelve cubes with dimensions of 150x150x150 mm. Another thirty cubes for each mortar and cement paste with dimensions of 100x100x100 mm were casted for the calibration of the drill bit sharpness. The most accurate and reliable equation in this research was the equation that was derived from the correlations between the average drilling penetration speed and the average concrete strength using 10 mm drill bit. The equation has the highest coefficient of determination (R2) value that equals to 0.94. The lower bound of this equation can be used to estimate the strength of concrete with higher level of safety. The findings of this study show that the drilling test method can be used to estimate the strength of in situ concrete more accurately than the conventional non-destructive tests and without causing major structural damage to the concrete member being tested