Enhancing The Performance Of Recycled Aggregate Concrete For Construction
| dc.contributor.author | ISMAIL, SALLEHAN | |
| dc.date.accessioned | 2016-05-03T02:49:55Z | |
| dc.date.available | 2016-05-03T02:49:55Z | |
| dc.date.issued | 2015-01 | |
| dc.description.abstract | This study aims to develop a modification method that can enhance the performance of recycled aggregate concrete (RAC) to encourage the widespread use of this material by the construction industry, particularly for structural applications. Hence, this experimental research provides insight into improving the various structures levels of RAC properties through multi-phase improvement processes. The first phase focuses on the treatment to improve the recycled concrete aggregate (RCA) properties before they are incorporated into the RAC mix by initially soaking coarse RCA in hydrochloric acid (HCl) at concentration of 0.5 mole and then impregnating these aggregates with a calcium metasilicate (CM) solution. The second phase involves the modification of the RAC mix through reinforcement with a different fibre system. Short discrete barchip and polypropylene fibres are used at various volume fractions and are added in single and hybrid forms. The effects of both surface treatments on the RCA properties before and after treatment are determined. This study also investigates the effectiveness of multi-phase modification with respect to the engineering and durability performance of the resultant RAC when exposed to various curing conditions, namely, normal water, open air and seawater. Moreover, the flexural behaviour of modified RAC beam is examined. Findings show that the physical and mechanical RCA properties significantly improve after surface treatment. The effect inclusion of the treated coarse RCA is significant in enhancing the engineering and durability properties of RAC. However, the further xxiv addition of fibre, particularly in hybrid form, can optimise the results. As shown in the results, the optimum compressive strength obtained by modified RAC in types HB4 (0.96% polypropylene + 0.24% barchip), where their compressive strength at 300 days in the corresponding curing conditions, can be significantly improved by 11% upto 21% higher than normal concrete. Moreover, other mechanical strength properties of modified RAC in terms of flexural strength, modulus of elasticity and impact resistance can also surpass to those of normal concrete and unmodified RAC. The effect modification is also found beneficial in improving the durability of RAC performance when exposed to an aggressive environment. Results indicate that the water absorption and intrinsic air permeability of modified RAC consisting of hybrid fibre can be reduced by up to 9% and 37%, respectively, after being exposed in the long term to seawater curing condition. Other durability properties, such as capillary absorption, chloride penetration, carbonation and dry shrinkage, are also found to be significantly reduced. The study on flexural behaviour reveals that the first crack load, ultimate load capacity and ductility of the modified RAC beam consisting of hybrid fibre can be remarkably enhanced by approximately 4%, 21% and 60%, respectively, higher than that of the unmodified RAC beam. | en_US |
| dc.identifier.uri | http://hdl.handle.net/123456789/1963 | |
| dc.subject | Enhancing The Performance Of Recycled Aggregate Concrete | en_US |
| dc.subject | For Construction | en_US |
| dc.title | Enhancing The Performance Of Recycled Aggregate Concrete For Construction | en_US |
| dc.type | Thesis | en_US |