Effects of static–fatigue (tension) on the tension–tension fatigue life of glass fibre reinforced plastic composites

The effects of static–fatigue interaction on tension–tension fatigue life of glass fibre reinforced plastic (GFRP) composites were investigated. This paper proposed a new static–fatigue model, which is capable of predicting residual strength after a period of static loading. Also an algorithm is proposed to calculate fatigue lives with the inclusion of static–fatigue interaction. Predictions from the proposed static–fatigue model show a good agreement with the experimental results. Static–fatigue interaction has shown a considerable effect on fatigue lives of GFRP composites at intermediate and lower applied stress levels possibly due to a longer exposure to applied loads. At higher load levels approximately greater than 65% of ultimate stress, and higher stress ratios range like 0.5 < R < 0.9, fatigue lives shown to be closer to material’s static–fatigue limits which is shorter than the expected lifetime by cyclic fatigue.     

Modeling of Moisture Loss in Cementitiously Stabilized Pavement Materials

The paper presents a theoretical and experimental approach for the modeling of moisture loss during the drying of cementitiously stabilized pavement materials containing varying contents of fine-grained soil. The process of moisture loss was characterized by the isotropic nonlinear diffusion theory. Laboratory tests were undertaken using general purpose Portland cement and two binders comprising industrial waste products. Measurement of material characteristics included the coefficient of moisture diffusivity and the humidity isotherm. Locally available basaltic crushed rocks and clay were respectively used as the host pavement material and fine-grained soil. Independent laboratory tests were undertaken to validate the adopted theoretical approach, which showed close agreement between the experimental and predicted results. The laboratory results indicated that moisture loss decreased with the inclusion of clay soil within the mix. As the drying progressed, the rate of moisture loss became slower, which can be explained by the reduction in the coefficient of moisture diffusivity with the decrease of moisture content.     

Floor Space per Person and Housing Development: An Urban Growth Approach to Estimate Housing Supply in Hong Kong

This article estimates an empirical model of new housing supply in Hong Kong based on the urban growth approach. The article introduces a new factor, space usage per person (SPP), to this model reflecting the quality of housing, the demand and supply aspects of the housing market, along with prices and other standard variables. SPP may also be used as a human settlement development indicator. Empirical results provide strong evidence that the introduced new factor exerts a strong positive influence on new housing supply, and that even a marginal change in the space usage pattern would have a great impact on housing supply. This suggests that non-price measures too should receive priority when estimating future housing development needs. Empirical estimates also suggest that a 10 per cent rise in real house prices leads to a 0.6 per cent increase in new housing starts and twofold rise in real house prices would increase the entire housing stock by 6 per cent.

     

Evaluation of engineering properties for the use of leached brown coal ash in soil covers

The need to engineer cover systems for the successful rehabilitation or remediation of a wide variety of solid wastes is increasing. Some common applications include landfills, hazardous waste repositories, or mine tailings dams and waste rock/overburden dumps. The brown coal industry of the Latrobe Valley region of Victoria, Australia, produces significant quantities of coal ash and overburden annually. There are some site-specific acid mine drainage (AMD) issues associated with overburden material. This needs to be addressed both during the operational phase of a project and during rehabilitation. An innovative approach was taken to investigate the potential to use leached brown coal ash in engineered soil covers on this overburden dump. The basis for this is two-fold: first, the ash has favourable physical characteristics for use in cover systems (such as high storage capacity/porosity, moderately low permeability, and an ability to act as a capillary break layer generating minimal leachate or seepage); and second, the leachate from the ash is mildly alkaline (which can help to mitigate and reduce the risk of AMD). This paper will review the engineering issues involved in using leached brown coal ash in designing soil covers for potentially acid-forming overburden dumps. It presents the results of laboratory work investigating the technical feasibility of using leached brown coal ash in engineered solid waste cover systems.