Study of hard base for permeable sidewalk pavement

• Main Author: 陳忠麟
• Other Authors: Shuh-Gi Chen
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/53510490743129941292

碩士 === 國立臺灣海洋大學 === 河海工程學系 === 99 === When the civilization intensifies, the trend of socialization worsens. Due to intensive urbanization, impermeable pavement replaces greens of urban grounds which are originally permeable and water preserving, resulting in rainwater falls in the urban area no longer being absorbed by and preserved in the soil but directly turning into runoff which, in turn, being drained into rivers and ocean via municipal drain systems. Therefore, the heavier the precipitation the worse loading to the urban area drain systems, thus causes severer impacts to the overall flood prevention system. In order to coexist with the nature and environment in the concept of pursuing a sustained development of the human habitat, construction related research institutes in the country have recently developed nine indexes for grading green buildings; where a site water retention index is introduced for assessing water retention performances of construction sites, in purposes for facilitating groundwater circulation, for improving the ecological environment, for regulating micro climates, and for mitigating urban temperature rise. Currently sidewalk pavements are constructed with soft bases in the country. Under Taiwan’s warm and rainy climate, the permeable pavement with soft base tends to form uneven settlements after being used for a certain period due to drift away of sandy layers from the soft base. In order to improve this effect, as well as for prolonging durability of the sidewalk pavement, department of new constructions, bureau of public works, Taipei city government has actively promoted hard-base permeable pavements constructed from permeable concrete and permeable resin mortar in year 2009. However, the high construction cost has limited the success of an extensive promotion. The study takes construction specifications, design drawings and detailed tables prepared by Department of New Constructions BPW TCG as the main scheme, deduces permeability coefficients of bases combining non-permeable concrete and aggregates of even gravels, with considerations of water retention requirements of green buildings and comfort and durability requirements of the sidewalk, attempting to lower construction costs of the permeable pavement so that it can be promoted more extensively. The improved permeable pavement with hard-base proposed by the study has a permeability coefficient of kT=8.210×10-3cm/s, which is higher than the permeability coefficient of soil (k is approximately 1.195×10-3cm/s) of the greater Taipei area, with a ratio of 6.87 folds; therefore this method is capable of guiding the surface runoff upon the sidewalk pavement into the soil, not only being capable of lowering the temperature and mitigating the need for an overall flood prevention effectiveness in the cosmopolitan area, but also being helpful to re-inject source water to aquifer and to facilitate cultivation of underground microscopic organisms. Furthermore, this improved permeable pavement with hard-base proposed by the study has a lower cost than the “high-pressure permeable concrete bricks” promoted by Department of New Constructions BPW TCG. We therefore hope that this study provides references for the promotion and feasibility analysis of permeable pavements.