Comparative Study On The Accuracy Of Comprehensive Strength Testing Machines Between City Engineer's Office And Department Of Public Works And Highways Of General Santos City

There are various testing laboratories that provide compressive strength test for concrete and it is important to verify the accuracy of the machines used for testing. This study concentrated on the comparison of the accuracy of compression machine of City Engineers" Office and Department of Public Works and Highways in General Santos City. More specifically, it seeks to determine the variability between the concrete compressive strength results from two testing laboratories. Furthermore, a control results from a private testing center, Mega Testing Center Inc., was utilized to determine which testing machine is more precise. In obtaining data, three (3) concrete cylinder samples for each testing laboratories and three (3) for control. A total of nine (9) samples were casted from the same batch and cured for 28 days. Compressive strength test was performed at the above — mentioned testing laboratories and analyses were done to obtain variability and significant percentage differences. Moreover, recent calibration records of the testing machines were also investigated to determine accuracy of machines. The result of analyses indicates that the accuracy of one testing machine varies more in one of the testing laboratories. Test results from Mega Testing with valid equipment calibration showed concrete results above required compressive strength for 28 days old concrete. CEO and DPWH results showed low strength concrete failing to meet required strength of 3,000 psi.