Browsing by Author "Barisanga, Fabrice"
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- ItemMaterial characterisation and response modelling of recycled concrete and masonry in pavements(Stellenbosch : Stellenbosch University, 2014-04) Barisanga, Fabrice; Rudman, Chantal; Jonathan Jenkins, Kim; Stellenbosch University. Faculty of Engineering. Dept. of Civil Engineering.ENGLISH ABSTRACT: The global quest for sustainability has intensified the requirement for waste recycling in a number of countries. Waste recycle includes Construction and Demolition Waste (CDW), which emanates from the demolition of buildings and other civil engineering structures. In Europe, the United States, China, and Australia, waste recycling has proven to be successful, both structurally and functionally. In particular, the consideration and /or use of CDW in pavement layers remain on the increase. However, in Southern Africa the use and/or application of CDW and its allied practice is limited; the abundant natural aggregates, the lack of knowledge and technical expertise besides the availability of suitable CDW remain the prominent reasons for its limited consideration. In this research, recycled material infers to Construction and Demolition Waste pertaining to Recycled Concrete and Masonry (RCM). The quality and the type of RCM vary from region to region and as a result, quality control measures aimed at limiting the inconsistency are usually required. Results revealed that secondary crushing influences the physical and mechanical behaviour of RCM aggregates; this information remains insightful in terms of material gradation, performance and viability. The compaction protocol followed and its findings revealed that the initial material grading lightly changed after compaction. However, the 10% FACT results showed that the RCM aggregates exhibit less degradation due to crushing when dry than when they are wet. It is eminent that compaction and/or densification are a cheaper method to improve the pavement layer structural capacity. However, this is reliant on material characteristics, quality, and type. With this cognisance, an experimental program in line with RCM aimed at assessing the mechanical behaviour was developed. The experimental variables include mix composition, mixing and compaction moisture as well as degree of compaction and/or compactive effort. In general, the laboratory evaluation and analysis of the results showed that the mix composition in addition to compaction moisture and the degree of compaction were influential to the obtained shear strength, resilient modulus and Poisson Ratio. Particularly, mix composition exhibited relatively higher influence on the resilient modulus while the compaction moisture effect on the Poisson Ratio dominated other investigated variables such as mix composition and the degree of compaction. Shear strength and resilient response results show that RCM exhibits significant shear strength due to its cohesion, and satisfactory resilient modulus. Pavement analysis and design using multi-layer linear-elastic model and transfer functions in pavement layers where RCM is used also revealed that this material could perform satisfactorily. It was deduced that RCM is a viable material type to consider in the construction of pavement layers that carry low to moderate levels of traffic.