01478732

Component

Concrete maturity method is a popular non-destructive testing method to estimate in-place strength development of concrete structures. Many state highway agencies adopted procedures for using maturity method to obtain better quality control while monitoring in-place strength development in real time. In this study, maturity method was used to estimate in-place strength of large concrete placements. Four 6-foot cube blocks were constructed in four different locations and calibration curves for those concrete mixtures were established using 6x12 inch cylinder specimens collected from the construction site. Temperature sensors were embedded in specific locations throughout the depth of the cubes, and the equivalent age of the in-place concrete was calculated. 4-inch diameter core samples, with 6-foot in length, were taken from the cubes at four-day after construction and the core strengths were compared with the predicted strengths using maturity. In addition, activation energy values were determined in the laboratory and used for equivalent age calculations as recommended in ASTM C 1074. According to the test results, the concrete top surface strength prediction is always higher than the actual core strength. For three cube constructions, core results from mid-section were close to the predicted strengths and core results from the bottom section were higher than the predicted values. Results show that in-place concrete strength is being influenced by several factors other than temperature, including the location of the sample in the structure, lack of compaction quality, higher air content and in-situ water-cement ratio, so that establishing a reliable maturity and in-place strength relationship is rather difficult within given circumstances. The results of this study provide useful information to examine the accuracy of the maturity method used in the estimation of in-place concrete strength in large structures.

This paper was sponsored by TRB committee AFN20 Properties of Concrete.

01470560

13-4969

English

14p

2013

Transportation Research Board 92nd Annual Meeting

Digital/other

Figures; Photos; References; Tables

Air content; Concrete structures; Nondestructive tests; Quality control; Strength of materials; Temperature; Water cement ratio

Bridges and other structures; Highways; Materials; I32: Concrete

Transportation Research Board Annual Meeting 2013 Paper #13-4969

PRP, TRIS, TRB, ATRI

Feb 5 2013 12:57PM