In this paper, the effect of the source of recycled coarse aggregate on the properties of concrete is investigated. The tests were conducted on concrete made from three sources of recycled aggregates： （1） old concr...In this paper, the effect of the source of recycled coarse aggregate on the properties of concrete is investigated. The tests were conducted on concrete made from three sources of recycled aggregates： （1） old concrete with unknown strength, （2） old concrete with a known compressive strength of 21 MPa, and （3） old concrete with a known strength of 42 MPa. The three sources of recycled aggregates were used to produce new concrete with a target compressive strength of 21 MPa. The first and third sources of recycled aggregates were used in producing concrete with target strength of 42 MPa. A control mix was designed with aggregates from natural sources. The research included two methods of making recycled concrete. One concrete mix was produced using the recycled aggregate and adding more water than the control mix, to reach the target slump, while the second concrete mix was produced using the same amount of water as the control mix but with additional superplasticizer to maintain the target slump. The results obtained in this research showed that the concrete compressive strength depends on the source of recycled aggregates; the stronger the source of recycled aggregate, the higher the compressive strength of the produced concrete. Furthermore, the compressive strength of the first concrete mix was about 10%-20% lower than the compressive strength of the control mix. However, when superplasticizers were used, the compressive strength was around the same value as the control mix.展开更多
This study tries to reveal the carbonation behavior when recycled coarse aggregates(RCAs) are used to mix new concrete.Six series of tests including 22 groups of recycled aggregate concrete(RAC) specimens were carried...This study tries to reveal the carbonation behavior when recycled coarse aggregates(RCAs) are used to mix new concrete.Six series of tests including 22 groups of recycled aggregate concrete(RAC) specimens were carried out,in which the effects of the water/binder(w/b) ratios,the binder content,the types of mineral admixture,the quality of RCAs,the RCAs replacement and the loading levels on the carbonation behavior of RAC were evaluated,respectively.The results showed that the carbonation behavior of RAC was not only influenced by the quality of new mortar but also by the properties of RCAs.The admixture of mineral admixture influenced the carbonation,and the loading stress level might have a significant impact on the evolution of the carbonation.展开更多
文摘In this paper, the effect of the source of recycled coarse aggregate on the properties of concrete is investigated. The tests were conducted on concrete made from three sources of recycled aggregates： （1） old concrete with unknown strength, （2） old concrete with a known compressive strength of 21 MPa, and （3） old concrete with a known strength of 42 MPa. The three sources of recycled aggregates were used to produce new concrete with a target compressive strength of 21 MPa. The first and third sources of recycled aggregates were used in producing concrete with target strength of 42 MPa. A control mix was designed with aggregates from natural sources. The research included two methods of making recycled concrete. One concrete mix was produced using the recycled aggregate and adding more water than the control mix, to reach the target slump, while the second concrete mix was produced using the same amount of water as the control mix but with additional superplasticizer to maintain the target slump. The results obtained in this research showed that the concrete compressive strength depends on the source of recycled aggregates; the stronger the source of recycled aggregate, the higher the compressive strength of the produced concrete. Furthermore, the compressive strength of the first concrete mix was about 10%-20% lower than the compressive strength of the control mix. However, when superplasticizers were used, the compressive strength was around the same value as the control mix.
基金supported by the National Natural Science Foundation ofChina (Grant No. 51178340)the Shanghai Science and Technology Committee (Grant No. 10231202000)the New Century Excellent Talentsin China Ministry of Education Project (Grant No. NCET-06-0383)
文摘This study tries to reveal the carbonation behavior when recycled coarse aggregates(RCAs) are used to mix new concrete.Six series of tests including 22 groups of recycled aggregate concrete(RAC) specimens were carried out,in which the effects of the water/binder(w/b) ratios,the binder content,the types of mineral admixture,the quality of RCAs,the RCAs replacement and the loading levels on the carbonation behavior of RAC were evaluated,respectively.The results showed that the carbonation behavior of RAC was not only influenced by the quality of new mortar but also by the properties of RCAs.The admixture of mineral admixture influenced the carbonation,and the loading stress level might have a significant impact on the evolution of the carbonation.
