Journal Published Online: 18 December 2018
Volume 48, Issue 6

Comparative Study on In Situ and Laboratory Testing of Concrete Cores with Different Height to Diameter Ratios

CODEN: JTEVAB

Abstract

The concrete core test is usually conducted to determine the compressive strength of hardened concrete at the site. A laboratory core test takes approximately 2 to 3 days as a result of operations like core cutting, transportation, curing, sawing, sulphur capping, testing, etc. In order to reduce processing time, an attempt was made to test the concrete core compressive strength at the site by fixing an in situ testing machine over the drilled core specimen with the help of anchor fasteners. The research was conducted using two types of in situ testing machines. Cores with diameters of 24 mm and height to diameter (H/D) ratios of 1, 1.5, and 2 were tested using machine 1. Similarly, cores of diameter 24 mm, 42 mm, and 67 mm with H/D ratio 1, 1.5, and 2 were tested using machine 2. The in situ compressive test results were compared with the results from the laboratory test conducted on an equal number of cores. Student t-tests were conducted between the results of both laboratory and in situ core tests. In all the cases, the t-statistical values were less than the t-critical, which indicates that there is no significant difference between both the methods. The results were analyzed for variation of core strength with respect to H/D ratio and diameter. It was observed that in both the in situ and laboratory core testing methods, the core strength decreased with an increase in H/D ratio and increased with an increase in core diameter. However, the variance in strength with increasing core diameter was proved to be not significant with the help of the ANOVA test. Multiplication factors used to determine the equivalent cube strength from the in situ core strength of concrete were calculated for corresponding diameters and H/D ratios.

Author Information

Reddy, Bijivemula Sudheer Kumar
Department of Civil Engineering, Visvesvaraya National Institute of Technology, Nagpur, Maharashtra, India
Wanjari, Swapnil Purushottam
Department of Civil Engineering, Visvesvaraya National Institute of Technology, Nagpur, Maharashtra, India
Shiva Kumar, Varun Yalehalli
Department of Civil Engineering, Visvesvaraya National Institute of Technology, Nagpur, Maharashtra, India
Pages: 16
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Stock #: JTE20170373
ISSN: 0090-3973
DOI: 10.1520/JTE20170373