Alkali-silica reaction (ASR) is one of the most severe attacks on concrete. There are several causes, one of which is the cracking of grains of slow/late aggregates in alkaline environment. Cracking can start in the interior of grains when there…
Alkali-silica reaction (ASR) is one of the most severe attacks on concrete. There are several causes, one of which is the cracking of grains of slow/late aggregates in alkaline environment. Cracking can start in the interior of grains when there are defects or when there are minerals inside which dissolve due to the action of pore solution in the concrete. A silica gel can develop and swell which causes interior pressure in the grain. Researchers have postulated that the stresses lead to failure of the grain as soon as the tensile strength of the aggregate is reached. The new approach states, owing to the brittle nature of the mineral aggregates, that the critical stress intensity is the limiting factor for failure and not the tensile strength [1]. So, fracture mechanics principles will be employed in order to illustrate cracking of grains as a reason for ASR. A test series has been carried out in order to prove the statement. Mechanical properties of various slow/late aggregates have been determined after exposure to alkaline environment for more than one year. It appears that the critical stress intensity factor decays such that cracking is feasible due to ASR.