Title: Accelerated Strength Test Results with Pozzolanic Cement Concrete

Author(s): Erbil Oztekin

Publication: Symposium Paper

Volume: 91

Issue:

Appears on pages(s): 231-248

Keywords: accelerated tests; cement content; compressive strength; concretes; cylinders; pozzolan cements; quality control; research; statistical analysis; water-cement ratio.

DOI: 10.14359/10072

Date: 2/1/1986

Abstract:
This study investigated the accelerated test results of pozzolanic cement concretes. The accelerated test method used is the ASTM C 684-74 Boiling Water Method. The Portland-Pozzolan cement used contains 30% natural pozzolan. The laboratory work involved the production of concrete mixes with cement contents of 300 to 450 kg/m3, water-cement ratios varying between 0.3 and 0.63. Maximum agregate size was chosen to vary between 15 and 40 mm and both gravel and crushed aggregates were used. 28 day compressive strengths ranged from 14.2 to 35.5 MPa. From each concrete mix five 150x300 mm cylinder specimens were cast. Accelerated cure was applied to two specimens cast in covered molds. The other three specimens were cured under standard conditions for 28 days. The production, curing, capping and testing of specimens were in accordance with the relevant standards. Analysis of the results reveal a power type relationship between the accelerated and the standard strength results and the coefficient of correlation was found as 0.967. The linear relationship also gives a high coefficient of correlation (0.963). Using the linear relationship 28-day strengths can be estimated with 2.4 MPa accuracy within 90% confidence limits. The relationship is compared to and found to be in agreement with those proposed by other investigators. However accelerated strengths given by the pozzolanic cement seems to be a little higher than the others.