Thermal+Insulation+of+Lightweight+Concrete

Lightweight aggregate concrete (LWAC) with various natural sand contents and fine aggregate compositions were made to investigate the thermal conductivity. In addition, the thermal insulating capability of hollow concrete blocks in relation to their void constitutions was also examined. Test results have shown that a decrease of the volumetric fraction of natural sand in lightweight aggregate concrete results in a smaller thermal conductivity value (K value). When bottom ash and lime sand are used as the fine aggregate, the K value of lightweight aggregate concrete can be reduced to about 39% and 23%. It was also found that a hollow concrete block could exhibit a lower K value by arranging more void layers is the direction perpendicular to the heat flow. With the same void content, the no-fine concrete possesses similar thermal conductivity to that of hollow concrete. Accordingly, the hollow concrete blocks and the no-fine concrete blocks, with the K value of only about 0.1 W/mK-0.2 W/mK, are proposed.本文除探討輕質骨材混凝土(LWAC)熱傳導係數受天熱砂含量及細骨材組成變化之影響，另外亦討論混凝土孔隙結構與中空混凝土隔熱能力間之關係。試驗結果顯示減少輕質骨材混凝土的天然砂含量，混凝土的熱傳導係數(K值)將降低。當低砂含量之底灰及石灰石砂充當作細骨材時，輕質骨材混凝土的熱傳導係數(K值)則分別降低39%及23%。本試驗也發現中空混凝土若孔隙排列在垂直於熱流方向者越多。則K值越小。若在相同的孔隙含量下，無細混凝土與混凝土空心磚有相近的熱傳導係數，而其K值最低者可達約0.1W/mK~0.2W/mK之間