EXAMPLE OF COMPOSITE DETERIORATION OF RC SLAB CAUSED BY ASR AND FROST ATTACK IN MOUNTAINOUS COLD AREAAND ITS VERIFICATION TEST

Abstract

 This study first discusses the mechanism of severe deterioration found in RC slab in a cold mountainous region. Based on the discussion, laboratory tests were conducted to clarify the mechanism of composite deterioration caused by ASR and frost attack. The tests investigated the effects of ASR expansion, types of alkali used for accelerating ASR, air content in concrete, and presence or absence, or position, of reinforcement in cross section. The test results showed that repeated cycles of freezing and thawing would cause very severe surface scaling on ASR-deteriorated concrete and continued expansion of concrete despite the low temperature. The deterioration process could not be slowed down by entrained air. The types of alkali used in the tests for accelerating ASR, or whether or not reactive aggregate was used only for the coarse aggregate, had no apparent impact on the degree of degradation.