Mixing Water Treatment Residual with Excavation Soil in Brick and Artificial Aggregate-Making
Jill Ruhsing Pan
|關鍵字:||淨水污泥;營建廢棄土;磚;人造骨材;Water Treatment Residual;Excavation Soil;Brick;Artificial Aggregate|
粉體分析顯示，淨水污泥成份中SiO2的含量偏低、Al2O3的含量偏高，至於營建廢棄土的成份則相當接近一般磚用黏土。淨水污泥的添加對燒結磚體的強度有負面的影響，在950℃的燒結溫度下，混合15%的淨水污泥抗壓強度只達到約100 kg/cm2。燒結溫度對磚體的強度影響很大，在1050℃的燒結溫度下，即使混合30%的淨水污泥，其抗壓強度依然可達到200 kg/cm2以上。另一方面，淨水污泥以1000℃、1050℃、1100℃製作燒結型人造骨材，其比重皆小於2。綜合比重、吸水率、抗壓強度的測試結果，淨水污泥燒結人造骨材與天然骨材相較，具有低比重、強度稍弱的特性，但符合作為輕質骨材應用的基本性質。|
Although water treatment residual (WTR) contains no hazardous chemicals, the increasing volume generated from water treatment has reached unmanageable level. The soil excavated from the ground before construction, essentially clay, is another big problem in this island. Currently, landfill disposal is the main waste management method for these two waste soils, which is not a practical solution because of high cost of transportation and the scarcity in land. Due to the nature of WTR and excavation soil (ES), recycling and reuse in construction materials has become a more popular way of treating them. In this study, sintering processes were attempted to make the waste soils into building brick and artificial aggregate. First, the chemical compositions of WTR and ES were analyzed using ICP-AES and the mineralogical composition was determined with X-ray diffraction. The chemical composition of ES was similar to clay. WTR had more Al2O3 and less SiO2 than ES. The compression strength result suggested that sintering temperature was critical in brick-making. Various amount of WTR was added to ES before sintering, and the sintering behaviors of the products from different sintering conditions were monitored. When sintered at 1050℃, the brick from samples containing 30% WTR could reach around 200 kg/cm2 compression strength. Bricks made from mixtures containing 15% WTR could reach 100 kg/cm2 compression strength when sintered at 950℃. The specific gravities of artificial aggregates sintered at 1000℃, 1050℃, and 1100℃ were all less than 2 kg/cm3. Results of specific gravity, water absorption, and compression strength suggested that WTR artificial aggregate could meet the general requirement for lightweight aggregates.