| 摘要: | 台灣地區隨著都會區下水道普及率的提升，預計民國98年下水污泥量將達40萬立方公尺/日，在掩埋用地與民眾抗爭難以處理的窘困環境下、使下水污泥的減量與資源化更加迫切。因此，本研究利用污泥焚化灰渣為主體材料，水泥提供適量鹼度與膠結性，以鋁粉或廢五金做為發泡劑，常溫製造下水污泥灰發泡輕質混凝土。在改變水泥/污泥灰比例、發泡劑用量及水固比等條件下，探討組成材料之基本性質、發泡行為、工程性質及受高溫作用之特性，並依據規範提出最適化之材料配比。同時藉由SEM、XRD及MIP等微觀分析技術，瞭解污泥灰發泡輕質混凝土於常溫及不同溫度作用下之微結構及物種變化。 實驗結果顯示，在發泡劑用量0.5%、0.9%、1.3%，水泥/污泥灰用量比例為40：60、30：70、20：80，以及水固比為0.5、0.6、0.7、0.8等配比條件下，污泥灰發泡輕質混凝土之密度與抗壓強度皆能達到中國國家標準CNS 13480「高壓蒸汽養護輕質氣泡混凝土磚」之比重1.2以下、抗壓強度2.5MPa之水準；污泥灰發泡輕質混凝土為多孔洞結構，其毛細管孔體積達84.7~96.4%，傳導率介於0.0845~0.1024W/m.K，僅一般混凝土之1/10~1/20，且低於一般市售ALC製品；污泥灰發泡輕質混凝土經1093℃焚燒後，因燒結作用使其密度與抗壓強度增加，當污泥灰用量增加其強度提升幅度越大，但體積收縮率反而增加，此現象需待改善。因此，利用污泥灰渣與廢五金粉常溫製造發泡輕質混凝土，不但符合減量、資源化與省能等功能，同時能提供質輕且經濟的環保建材。 Due to the wider coverage of sewer system in urban areas, it is predicted that the sewage sludge generated from pipe-end treatment plants in Taiwan will amount to 400,000m3 by the year 2009. Decreasing landfill sites, exacerbated by the continuing residents’ protest, has called for an urgent need for reducing and recycling sludge. In recognition of this, this study tried to produce lightweight concrete by using sewage sludge ash as main material, combined with cement and pulverized scrap metal. Cement was used to provide with proper alkalinity and work as binder, and pulverized scrap metal (mainly aluminum) and aluminum powder were used as vesicants. Primary factors influencing the bloating mechanism and engineering properties of the resultant lightweight concrete including cement/sludge ash ratio, vesicant quantity and water-to-solid ratio were varied to investigate the characteristics of the composite materials, their bloating mechanism, engineering properties of the resultant lightweight concrete, and its effect subject to high temperatures. Microanalysis was conducted on species changes and microstructure variations in the resultant concrete at tested temperature by applying SEM, XRD and MIP techniques Moreover, the optimum mix design was proposed based on CNS 13480“Autoclaved Lightweight Aerated Concrete Block.” The results showed that under a mix design using 0.5%, 0.9% and 1.3% vesicant, with cement to sludge ash ratios ranging from 40：60, 30：70 and 20：80, and a water-to-solid ratio from 0.5, 0.6,0.7, and 0.8, the resultant sludge-ash-lightweight- concrete satisfied, in terms of density and compressive strength, the standards of CNS 13480 of which the requirements for specific gravity and compressive strength are <1.2 and 2.5MPa., respectively. The capillary pore volume of the resultant sludge—ash-lightweight-concrete fell in the range of 84.7%~96.4%; the thermal conductivity of the resultant concrete ranged from 0.0845~0.1024W/m.K, a value half of that of the ordinary concrete and lower than that of commercial ALC products. Heating test at 1093℃ showed that an increase in the density and compressive strength of the tested concrete specimen took place concurrently with the sintering of the concrete. Moreover, increasing the amount of sludge ash tended to increase the compressive strength of the concrete to some extent; however, a positive correlation between the degree of strength development and volumetric shrinkage suggested there was still room for further improvement. In conclusion, making blowing lightweight concrete with sludge ash and waste-metal power not only satisfies the requirement for waste reduction, recycling and energy conservation but also offers a light, economical and environment-friendly building material. |
