| Summary: | 碩士 === 國立臺北科技大學 === 土木與防災研究所 === 102 === The technology of producing lightweight aggregate from reservoir sludge has been developed for years in Taiwan. Many manufacturers have invested in mass production of lightweight aggregate with various properties such as heat insulation, sound insulation, fire resistance, etc. Such material has been used in construction engineering and meets green building standards. Traditional sand and gravel aggregates can be replaced with lightweight aggregates to mix lightweight concrete and it was successfully used for the bridge construction on national rout 6. The Ministry of Transportation and Public Constructions Committee continue to promote the use of lightweight aggregate in public constructions. The lightweight aggregate produced by using reservoir sludge, due to its porous characteristic, when used to manufacture lightweight permeable bricks, are suitable for use in landscape or outdoor pavement, such as square, sidewalk, landscape trails and bike paths, etc. It can also be used at riverside and slope protection for disaster prevention purposes. The lightweight aggregate achieves waste recycling and ecological environmental protection goals. In addition to the efficient resource utilization of reservoir sludge, the lightweight aggregate meets the concept of green environmental protection.
In this study, the lightweight aggregate manufactured using Shimen Reservoir sludge was sieved and classified according to particle size into three groups: coarse (1/2″to 3/8″), medium (3/8″to 1/4″) and fine (1/4″~ # 8). Water-permeable bricks were made using each group of lightweight aggregate under the condition of fixed amount of cement (360kg/m3) and water-cement ratio to investigate the relationship between coefficient of permeability and compressive strength of lightweight aggregate of coarse, medium and fine particle sizes. The permeable bricks produced in this study weigh about 1300~1600kg/m3 having coefficient of permeability of 10~100×10-2cm/sec and compressive strength of 220~320kgf/cm2. With the same amount of cement, water-cement ratio and vibration condition, the comparison result of the coefficient of permeability was coarse > medium > fine group. The result of the compressive strength was medium > coarse > fine group. The result of coefficient of permeability corresponds to the size of void of the particle size from large to small while the result of compressive strength is greater for medium particle size. This is because medium size particles are wrapped more completely and evenly in cement paste and the paste linkage between particles is more complete and thus fully giving the strength of cement paste.
Further, the three groups of materials were mixed and compared. The results revealed that the compressive strength of the bricks made of mixed material is only slightly greater than the bricks of coarse particles and less than the bricks of medium particles while the permeability of the bricks made of mixed material is in between of the bricks of medium particles and those of fine particles.
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