Flatness, levelness and plastic shrinkage cracks are three important parameters in the evaluation of the performance of concrete floor surfaces. The rapidly developing concrete floor industry overseas has resulted in a great deal of improvement in the methods for evaluation of surface flatness and levelness. This research encompasses a review of the development and evolution of codes in other countries, an evaluation of the current status in Australia, and reliable evaluation methods for concrete floors. The end result aims to present a comparison of the varying degrees of reliability of the different methods of measurement theoretically and demonstrates the feasibility of specified tolerance through the analysis of field data from actual projects. It also analyses the general assumption that concrete slabs exposed to hot weather conditions soon after casting is prone to plastic shrinkage cracking and its implications. Identifying factors influencing flatness, levelness and plastic shrinkage cracking of concrete slab surface and investigation of their effects are included in this research. Through statistical analysis, significant factors, such as the construction method, environmental conditions and the method of measurement are identified. In addition, sunlight intensity and capacity of concrete bleeding were factors investigated with regard to concrete surface evaporation rate. The monitoring of plastic shrinkage crack initiation and development is an important task in the research of concrete slabs. The research on plastic shrinkage cracking of the slab surface resulted in the development of a digital image analysis method. This method focuses on mapping cracks (MC) and measuring crack width (MCW). Other information such as crack growth over time can also be obtained based on MC and MCW. An accurate method for the measurement of crack width has been developed based on sliced crack image data. Therefore, this method can determine the location of the maximum crack width and measure it with a desired precision.
| Identifer | oai:union.ndltd.org:ADTP/187415 |
| Date | January 2005 |
| Creators | Wang, Xiaobo, Civil & Environmental Engineering, Faculty of Engineering, UNSW |
| Publisher | Awarded by:University of New South Wales. School of Civil and Environmental Engineering |
| Source Sets | Australiasian Digital Theses Program |
| Language | English |
| Detected Language | English |
| Rights | Copyright Xiaobo Wang, http://unsworks.unsw.edu.au/copyright |
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