دانلود رایگان مقاله انگلیسی ارزیابی خواص مکانیکی، دوام و بررسی چرخه عمر بلوک های بتنی - الزویر 2018

Abstract:

This paper aims to explore the possible use of recycled concrete aggregates (RCAs) to produce concrete building blocks. Laboratory test and plant trial were carried out to manufacture concrete building blocks incorporating 75% RCAs. A series of tests were conducted to investigate the mechanical and durability properties of the recycled aggregate concrete (RAC) blocks. The compression and shear performances of masonry prisms built with RAC blocks and conventional mortars were experimentally studied too. Furthermore, the environmental impact of RAC blocks was studied using life-cycle assessment (LCA) method. Five different environmental impact categories (i.e., GWP, AP, EP, HTP, POCP) are calculated and comparatively analyzed. The effect of RCAs on the mechanical and durability properties, as well as the environmental impact of RAC blocks was investigated. The test results indicate that the incorporation of RCAs slightly declined the compressive strength and impaired the durability of the concrete blocks. Nevertheless, concrete building blocks incorporating 75% RCAs satisfied the strength, drying shrinkage and freeze-thaw resistance requirements for concrete building blocks specified by Chinese standard. The compressive and shear performances of masonry prisms constructed with RAC blocks are similar to those of conventional concrete masonry. RAC blocks have less environmental impact compared to normal concrete blocks. It is feasible to use RCAs to manufacture concrete building blocks along with environmental benefits. The use of RAC blocks plays a key role in ending the building life cycle and will improve the sustainable development of masonry structures.

5. Conclusions

This research aims to develop a technique for manufacturing concrete building blocks incorporating RCAs. Laboratory test and plant trial were carried out to manufacture the concrete blocks incorporating 75% RCAs. A series of tests were carried out to investigate the mechanical and durability properties of the RAC blocks as well as the mechanical performances of the masonry prisms constructed with RAC blocks. The environmental impact of the RAC blocks was studied using LCA method. The test results and discussions allow the following conclusions to be drawn:

(1) The RCAs slightly impaired the mechanical and durability properties of the concrete blocks. Nevertheless, the concrete building blocks made with 75% RCAs exhibit favorable mechanical and durability performances and satisfy the performance requirements specified by Chinese 435 standard for concrete building blocks.

(2) The strength of the RAC blocks manufactured in the local plant is similar to that of the laboratory trials, indicating that it is viable to produce RAC blocks used in multi-story buildings by an industrial process.