含泥量是指粗細粒料中尺寸非常微小的部份,一般均為級配中尺寸小於75 μm(200號標準篩)的部分。本研究探討不同河砂含泥量對水泥砂漿性質的影響。並以水灰比0.485之水泥砂漿,含泥量變數為0%至9%做為實驗設計變數製作試體。相關試驗方面,利用流度試驗評估工作性質的影響。由抗壓強度與長度變化評估水泥砂漿硬固性質。由壓汞儀試驗探討含泥量對水泥砂漿孔隙結構的影響。經由試驗結果可發現當河砂含泥量大於5%以上時,無論工作性與抗壓強度均有降低情形。而由水泥砂漿孔隙結構發現,當河砂含泥量大於5%以上時,小於孔徑100 nm的孔隙有增加之趨勢,並發現含泥量會影響孔隙結構,進而影響水泥砂漿工作性與力學性質。對長度變化結果而言,會隨著河砂含泥量增加而水泥砂漿減少收縮情形。建議未來若需使用高含泥量河砂於水泥砂漿或混凝土組成材料時,含泥量不得高於5%。
Fines are fine aggregate particles smaller than the 75 μm (No. 200) sieve. This research investigates the effect of fines content on the properties of mortar. Mortar specimens with a w/c ratio of 0.485 and different fines content of fine aggregate, ranging from 0% to 9%, were cast and tested in this study. Flow table test was conducted to investigate the workability of mortar. Compressive strength test and length change test were study the hardened properties of mortar. And the mercury intrusion pressure was used to study pore structure of mortar. Test results indicate a decrease in workability and mechanical properties of mortar when the ratio of fines content exceeds 5%. The pore structure of mortar, however, when fines content was large than 5%, increases the intrusion pore volume at the pore radius is smaller than 100 nm. As results of the length change test, the mortar reduces the shrinkage as the fines content increases. It is also recommended that when using high fines content of river sand in mortar or concrete as composition materials, the fines content should not exceed 5%.