破碎卵石再生混凝土折压比试验研究

以废弃混凝土粗骨料作为再生粗骨料取代破碎卵石粗骨料，设计取代率r分别为0%、15%、30%、45%，并以此为基础分别制作破碎卵石再生混凝土立方体试件、棱柱体试件各36个，并在试件养护龄期分别为3、14、28 d时，分别对其进行抗压强度、抗折强度试验。分析了在不同龄期下，破碎卵石再生混凝土抗压强度与抗折强度随r变化的规律，以及r对破碎卵石再生混凝土折压比与类折压比的影响。结果表明：不同龄期下，随着r的增加，抗压强度、抗折强度的变化趋势均表现为先增后降，当r=30%时，抗压强度、抗折强度达到最大值；3 d龄期下，折压比与类折压比随r的增加无统一显著变化规律；14 d和28 d龄期下，随着r的增加，折压比与类折压比均呈先增大后减小趋势；且在28 d龄期下，r=30%时折压比与类折压比均达到最大值，分别建立了基于取代率r的折压比与类折压比计算公式。

Experimental Research on the Compression Ratio of Recycled Crushed Pebbles Concrete

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.