Comparative study on accelerated tests for determining alkali reactivity of concrete aggregates

For assessing the applicability of Chinese Accelerated Mortar Bar Test(CAMBT) for alkali reactivity of concrete aggregates to oversea's rocks and the correlations between CAMBT and other accelerated tests, i.e. Accelerated Mortar Bar Test(AMBT), Chinese Autoclave Method, expansion behaviors of 11 aggregates from different origins were studied in the Concrete Prism Test(CPT) and in various accelerated tests. The effect of aggregate particle size on aggregate expansion in the CAMBT was also studied. Results show that the outcomes for the aggregates from different accelerated tests are in agreement, but none of these tests can properly predict the reactive characteristics of all the aggregates with exaggerating the alkali reactivity of RG aggregate and failing to recognize the alkali reactive character of PO aggregate. There is no satisfactory correlation between expansion rates in the existing accelerated tests and in the CPT. Expansion rates in accelerated tests can not determine the reactive degree of concrete aggregates. The aggregate particle size has different influences on various aggregates and the 0.15~0.80 mm particle is not the most sensitive size to aggregate expansion in the CAMBT. With 2.5~5.0 mm aggregate particles, the reactive character and reactive degree in concrete of most of the tested aggregates can be satisfactorily predicted in the CAMBT.