Title: CAPO-TEST to Estimate Concrete Strength in Bridges

Author(s): Andrzej T. Moczko, Nicholas J. Carino, and Claus Germann Petersen

Publication: Materials Journal

Volume: 113

Issue: 6

Appears on pages(s): 827-836

Keywords: CAPO-TEST; carbonation; core strength; correlation; existing structures; in-place strength; pullout test

DOI: 10.14359/51689242

Date: 11/1/2016

Abstract:
This paper addresses whether carbonation in existing concrete structures affects the compressive strength estimated using the CAPO-TEST, a post-installed, pullout test conforming to ASTM C900 and EN 12504-3. Fifteen bridges, ranging from 25 to 52 years of age at the time of testing, were investigated. For each bridge, average values of core strengths and CAPO pullout strengths were obtained. Carbonation depth, which varied from 2 to 35 mm (0.08 to 1.4 in.), was measured using chemical staining methods. It was anticipated that, as the depth of carbonation increased, the pullout strength would increase for the same underlying concrete strength. Thus, the in-place compressive strength estimated on the basis of the manufacturer’s general correlation would be expected to systematically exceed the strength measured by the cores. It was found that, on average, the compressive strength estimated from the CAPO-TEST and the general correlation was only 2.8% greater than the measured core strength. More importantly, there was no correlation between depth of carbonation and the relative error of the estimated strength based on the CAPO-TEST.