Title: An Accelerated Method of Estimating the 28-Day Splitting Tensile and Flexural Strengths of Concrete
Author(s): V.M. Malhotra
Publication: Symposium Paper
Appears on pages(s): 147-168
Keywords: accelerated tests; compressive strength; concrete pavements; flexural strength; quality control; regression analysis; research; splitting tensile strength; tensile strength
In recent years there has been an increasing acceptance of accelerated strength tests for routine quality control of concrete and to estimate the 28-day compressive strength. However, very little, or no data, are available as to the use of accelerated strength tests for estimating the potential splitting-tensile strength and modulus of rupture of concrete. This study reports results of an investigation to determine the possibility of using the boiling procedure as an accelerated splitting-tension test. A total of twenty-two concrete mixes were made in the laboratory using limestone and natural sand as coarse and fine aggregates respectively. A total of 176 cylinders, 6 x 12 in. (152 x 305 mm) in size, and 44 prisms, 3.5 x 4 x 16 in. (89 x 102 x 466 mm) in size, were tested. The cylinders were tested in splitting-tension after accelerated- and moist-curing, and the prisms were tested in flexure after moist-curing. The correlations between the splitting-tensile strengths of accelerated-cured specimens and those of moist-cured specimens were statistically significant. The average within-batch variation for the splitting-tensile strength of accelerated-cured specimens was 5.1 per cent; the corresponding value for the strength of the 28-day moist-cured specimens was 5.7 per cent. From the analysis of the test results, it is concluded that the accelerated splitting-tensile test appears to be an adequate means for controlling the quality of pavement concrete. Those contemplating the use of the accelerated test for predicting the later-age splitting-tensile and flexural strengths of concrete are cautioned that they should develop their own correlations to allow for the variations in aggregates and cements.