In this paper, asphalt mix design methods are evaluated for their use in constructing high quality roads and in minimising permanent deformation in asphalt layers. The Marshall and Hveem mix design methods were used to design five mixes which were subjected to dynamic and static testing. Split tensile strength, resilient modulus and static creep tests were conducted on specimens prepared by both methods in order to compare their ability to evaluate mixes based on the rutting susceptibility. The results indicated that Hveem mix design method seems applicable to local roads, since it can design and identify mixes which have better engineering properties than those designed by the Marshall method.
The purpose of this paper is to briefly describe the Accelerated Loading Facility (ALF) machine and to summarise the aims, findings and benefits of the six trials conducted to date and the aims and expected outputs of the current trial and the next trial which is not due to be completed until March 1993. Since July 1984, six trials have been completed in four Australian states, during which 78 experiments have been conducted and 13 million load cycles (157 million ESAs) have been applied to 31 pavement types at 65 test sites. The types of pavements tested include heavy duty unbound crushed rock and macadam pavements, cement-treated crushed rock pavements, unbound and stabilised slag pavements, asphalt overlay and rehabilitation treatments including modified binders, and full depth asphalt pavements. Future trials will include testing of geotextile seal, gravel, fine-grained and bitumen-emulsion stabilised pavements. Some comments are also offered in the paper on the results of the FORCE study and how the extensive work already conducted in Australia, and planned for the future, could contribute to this study.
Rice husk ash (RHA) has been investigated as a pozzolanic material for soil stabilisation. It contains siliceous and aluminous materials, and reacts with lime or cement, thus having the economic potential to replace some of the lime or cement presently used as an additive in the stabilisation of soil. Three types of soil were treated with varying quantities of lime, cement, RHA and combinations of RHA with lime or cement, under laboratory conditions. To determine the effectiveness of RHA as a stabiliser, unconfined compressive strength (UCS), plasticity index and linear shrinkage were measured for the treated soils A using standard Road Traffic Authority of New South Wales (RTA NSW) tests. RHA alone was shown to be unsuitable for modifying soil properties. However, when combined with lime or cement, beneficial results were obtained. The effectiveness of the RHA was expressed in terms of the ratio of the RHA required to either lime or cement saved. RHA is produced by the burning of rice husks (also known as rice hulls), which currently are a little-used by-product of the rice industry, presenting disposal problems worldwide. Information on present and likely future availability of RHA in Australia is included in this paper.
A travel time function proposed by Davidson for transport planning purposes has been subject to much discussion and efforts of calibration including some controversy over the meaning of its parameters. Modified forms of Davidson's function have been proposed to obtain finite values of travel time for flows near and above capacity. This paper presents a time-dependent form of the original Davidson function, derived by using the coordinate transformation technique. The modified form of Davidson's function proposed recently by Tisato (1991) is shown to overpredict travel times for flows near and above capacity compared with the time-dependent form. The derivation of the original Davidson function is discussed and it is concluded that the function suffers from an inconsistency in its basic parameter definitions. An alternative interpretation of the delay parameter is considered, but this leads to another inconsistency. A new travel time function is proposed as an alternative to Davidson's function to overcome the conceptual and calibration problems. In the proposed function, the delay parameter takes a meaning consistent with the formulae used for estimating intersection delays. Both the steady-state and time-dependent forms of the new function are given.
The Monash University Accident Research Centre is a relatively new organisation. Over the last four years, it has grown to the stage where the Centre is now undertaking a comprehensive road safety research program for a range of national and state organisations. This paper outlines the objectives and management of MUARC and describes the major projects in the current work program. Language: en
