摘 要 混凝土材料為現今最普遍使用的營建材料之ㄧ,廣泛運用於各類型的營建工程,為瞭解於現地施工過程中各種可能影響混凝土強度品質之因素,本文以一實際工程案例為探討對象,提出傳統混凝土品質管制作業中可能造成強度高估不保守之各種情形,供業界參考,期使國內混凝土施工品質管理作業更臻完善。 本研究藉由一新建工程案例,完整追蹤各工程營繕的流程,於鋼筋混凝土結構物施工中,探討管頭及管尾混凝土強度之差異,各種養置方式對混凝土強度之影響,以ACI 214規範建議品管方式評定混凝土強度均勻度偏差情形,利用非破壞性試驗包括衝錘及超音波試驗評估現地結構體強度,並由國內鋼筋混凝土建築物耐震能力評估法及程式(靜力方式)作結構體耐震能力評估。 研究結果發現,管頭取樣試體較管尾取樣試體強度高,持續濕置養護較完全氣乾養護之試體強度佳,其強度差異較管頭與管尾取樣之試體強度差異性大;而高溫養護較正常程序養護之試體強度較高且有掺料效應提早反應之現象,但長期強度則有劣化趨勢。以破壞性試驗所得之結果較非破壞性試驗值高,委外實驗室之結構體各樓層強度及均勻度變異情況皆明顯較本實驗室結果高,依靜力耐震評估分析結果,各試驗強度值之耐震能力值皆符合規範,在試驗強度符合韌性設計範圍內,構件強度越高會韌性容量減低有整體耐震能力降低之現象。
Abstract In nowadays, concrete is the most common construction material used in all types of building projects. In this research, the quality control on concrete of a construction project of a multi-story building is followed. Investigate is focus on all the possible field factors that will affect the quality of concrete. The data are analyzed and conclusions are made for future improvements. The construction project is a new reinforced concrete multi-story building. Fresh concrete samples are taken before and after the pumping pipe in order to investigate the influence of the pipe transportations. Aslo, non-destructive tests, such as the Schmidt hammer and ultra sonic transmission, are carried out on both concrete samples and in-situ structural members. Finally, the earthquake resistance capability of the whole structure is studied based on the actual concrete strength. Results show that, strength is higher when samples are taken before the pumping pipe. With wet curing of samples, a even higher strength is obtained than those cured in air. Cured with high temperature produces higher short term strength, but has adverse effect of long term strength. On all cases, strengths produced by commercial test laboratories are higher than that produced by our own laboratory. Based on earthquake analysis with actual concrete strength, which is higher than the design strength, the earthquake resistance capability of the structure still fulfill the code requirements, though a reduce in toughness is found.