| Road recycled concrete (RRC) is a kind of sustainable developing energy-saving and environment friendly concrete. On the basis of experimental and theoretical analysis, the road performance and economy of recycled coarse aggregate (RCA) and recycled concrete (RC) are system analyzed and researched. The main contents includes:First, waste concrete source in Chongqing is investigated and classified. New processing technique of RCA is proposed according to requirement for enhancing quality of RCA, saving energy and production cost, and reducing pollution.Second, physical mechanics performance of RCA is experimental studied. The test shows that physical mechanics performance of RCA is poor than that of NCA. It is necessary that RCA is set up grading standard. The grade index includes density,water absorption, content of elongated and flaky particles, crushing strength, L.A. abrasion value, and impact value and so on.Third, the road performance of common recycled concrete (RC), fly-ash recycled concrete (FRC), polymer modification recycled concrete (PMRC), and interface modification recycled concrete (IRC) is experimental studied, including workability, mechanics strength, fracture mechanics performance, impact resistance performance, abrasion performance, sulphate resistance performance, dry-skrinkage performance. The total tests show replacement rate of RCA is no more than 50%, but the performance of RC can be improved when the replacement rate of RCA is 100%. The improving measures following:i) The fly-ash is mixed when the equal replacement rate of fly-ash is no less than 10%, and the excess replacement rate of fly-ash is from 1.0 to 1.4.ii) The polymer milk is mixed when polymer ratio is no more than 0.15.iii) Interface of RCA can be modified by some measures. The effect of both mechanical wear way and surround by cement paste are better than that of prewet way.The tests also show, not wear depth but wear loss is evaluation indicator of abrasion performance of RC. Meanwhile, compared to the change of compressive strength, the change of splitting tension strength is better as evaluation indicator of sulphate resistance performance of RC.Finally, after analyzing endogene effects and external effects of RCA application engineering, economic indicators are found. Benefits-cost analysis models are proposed to find the best economic program.The aim of this paper is for giving theory and technique reference to the application and promotion of RC in road. Meanwhile, it is one good way to modification works of old concrete and rural highway engineering. |
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