The objective of this research project has been to develop a computer controlled cyclic simple shear apparatus and to investigate the repeated load behaviour of local basecourse aggregates with regard to their shear modulus and volume change properties. A detailed discussion of the construction of the apparatus and the development of the control systems is presented. A review of the litreature regarding cyclic load testing of basecourse aggregates has been undertaken and presented in this thesis. A large number of shear displacement controlled cyclic simple shear tests were carried out using three types of local Auckland aggregate. A comparison of the performance of these materials is presented with particular emphasis placed on the shear modulus, volume change and particle degredation properties. High repitition cyclic simple shear tests have revealed an apparent stiffness recovery for granular specimens between test runs. This behaviour is difficult to explain, however it is thought to be related to the transition from a dynamic to a static state of friction within the specimen. The volume change properties of granular specimens have been found to be equivalent to the 'normally consolidated - over consolidated' behaviour of fine grained soils. This observation is consistent with that reported by Youd (1970) who performed similar tests using specimens of sand. The implications of this result are discussed with respect to the potential application to highway engineering. A number of shear stress controlled cyclic simple shear tests have been performed to investigate the applicability of a stability threshold for basecourse materials. The stability threshold, or shakedown behaviour, has been observed and is incorporated in a philosophy for pavement design. An example of this method has been performed to show the potential merits of including stability threshold data in the pavement design procedure.
| Identifer | oai:union.ndltd.org:ADTP/247540 |
| Date | January 1991 |
| Creators | Peploe, Ross John |
| Publisher | ResearchSpace@Auckland |
| Source Sets | Australiasian Digital Theses Program |
| Language | English |
| Detected Language | English |
| Rights | Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated., http://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm, Copyright: The author |
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