Abstract:Waste concrete coarse aggregate used as recycled coarse aggregate was applied to replace crushed pebble coarse aggregate. The replacement ratio r was 0%, 15%, 30% and 45%, respectively. Based on this, 36 cube and prism specimens of recycled concrete with broken pebbles were made respectively, and when the curing ages were 3 d, 14 d and 28 d, the compressive strength and flexural strength tests were implemented. The variation law of compressive and flexural strength of crushed pebbles recycled concrete with r at different ages and the influence on the compression ratio and class discount ratio of crushed pebbles recycled concrete with r were analyzed. The results indicate that: With r increasing, the trends of change of compressive strength and flexural strength increase at early stage and then decrease at different ages. When r=30%, it reaches maximizing compressive strength and flexural strength. At the age of 3 d, there is no uniform and significant change pattern in the compression ratio and the analogous compression ratio as r increases. At the age of 14 d and 28 d, with the increase of r, both the compression ratio and the similar compression ratio first increase and then decrease. At the age of 28 d, when r=30%, both the compression ratio and the similar compression ratio reached their maximum values. The calculation models of the compression ratio and the similar compression ratio based on the replacement rate r were established respectively.