Content area
Full text
A large-scale regression analysis was carried out using experimental data gathered from various sources to evaluate the ratio of splitting tensile strength to cylinder compressive strength as a function of compressive strength of concrete. The reliability of the proposed equation based on experimental data for compressive strength ranging between 4 and 120 MPa (580 to 17,400 psi) was assessed by means of the integral absolute error (IAE). It is also shown that, by only knowing compressive strength and the ratio of tensile to compressive strength, the failure envelope for very high-strength concrete can be established using Johnston's strength criterion without performing triaxial compression tests. A numerical example demonstrates the application of Johnston's strength criterion.
Keywords: compressive strength; confinement; high-strength concrete; splitting tensile strength; stress.
(ProQuest Information and Learning: ... denotes formulae omitted.)
INTRODUCTION
The ratio between tensile strength and compressive strength is an important material property of concrete. The value of this ratio is required for the following applications:
1. With respect to Bortolotti's studies,1,2 the ultimate strain value in uniaxial tension is expressed in terms of this strength ratio.
2. According to Johnston's strength criterion3 for intact rock under triaxial compression, the material constants defining the failure envelope are related to the ratio of compressive strength to tensile strength. Reported results of Setunge et al.4 and Yapι Merkezi5 for very high-strength concrete in triaxial compression are in good agreement with the strength criterion proposed by Johnston.
3. There are three types of tests to measure strength in tension: direct tension, flexure, and splitting tension.6 It has been well established that the simplest and the most reliable method, which generally provides a lower coefficient of variation, is the splitting tensile test7-9 of a cylindrical specimen. In this test, a cylindrical specimen is loaded in compression diametrically between two plates. According to the theory of elasticity, this loading generates almost uniform tensile stress along the diameter, which causes the specimen to fail by splitting along a vertical plane. The splitting strength f^sub tsp^ can be used to estimate direct tensile strength f^sub t^ by multiplying by a conversion factor of λ = 0.9, as given in the CEB-FIB Code10 and by Hannant et al.7
The objectives of the investigation reported herein are as follows:
1....