Correlation of compressive strength and flexural tensile strength of blended cement concrete

Abstract

Eurocodes for structural designs have been adopted for Sri Lanka. Hence in Sri Lanka, concrete designs need to be in compliance with the relevant Eurocodes – mainly EN1992 (EC2). In EC2, concrete is categorized by its compressive strength. The other strength parameters are derived from the compressive strength using correlations based on empirical data. A recent trend has been the increasing use of blended cement for concrete in certain applications. But the correlations specified in EC2 are based on data probably related to Ordinary Portland Cement (OPC) concrete. It is important to examine whether the correlations listed in EC2 are applicable to blended cement concrete too. The present study was performed to experimentally examine the correlation of compressive strength and flexural tensile strength of blended cement concrete. A parallel study was conducted for OPC concrete to serve as a baseline reference. Standard beam and cylinder specimens of concrete were cast, cured, and tested for flexural tensile strength and compressive strength. Three different mix ratios were used. Each mix was tested twice. The same series of tests were conducted for blended cement (Portland Composite Cement – PCC) and for OPC. Experimentally measured values of flexural tensile strength were compared against their estimated values derived from the experimentally measured compressive strengths, using EC2 listed relationships. The analysis showed that in the case of both OPC as well as PCC, the measured values of the flexural tensile strength exceeded their estimated values based on EC2 relationships. But the testing conducted has been limited in the number of tests performed, the range of mix ratios, and the types of aggregate used. In order to affirm the general applicability of Eurocode 2 relationships for blended cement concrete also, additional more comprehensive testing is warranted across a wider span of mix ratios and aggregate types.