玻璃纖維水泥複合材料之基本力學性質研究

Abstract

本文內容主要為以三種纖維長度、纖維含量及水灰比作為變數，以 噴送法(Spray-up Method)製成玻璃纖維砂漿（GRC），探求玻璃纖維 於水泥砂漿中之短期載重強度，（包括抗壓、抗拉、抗彎及抗剪強度） 以及對韌性行為之影響與乾縮應變之抑制情形。 豏“峞C 於本試驗結果得知，最佳強度提昇量，抗拉強度為普通水泥砂漿之 1.82~3.20倍，抗彎強度為2.14~3.30倍，抗壓強度為1.27~1.48倍， 抗剪強度為1.33~1.45倍；單位纖維量所發揮之抗拉與抗彎強度以wf= 3%組最佳。因纖維之束制作用，故抗壓強度隨著荷載之方向不同而不 同；長度較長之纖維，隨著纖維含量之增加能較有效地發揮抗拉與抗 彎強度，但若配合著低水灰比及高纖維含量則GRC材料會因施工性不良 而有多孔性質而影響強度。 多孔性質而影響強度。 GRC材料較普通水泥砂漿有優異之韌性表現，纖維含量wf=5%之韌性 韌 性指數 介於68.9~98.9之間；隨著水灰比的降低，GRC之極限抗彎強 度 隨之提昇，但韌性有降低之趨勢。玻璃纖維對乾縮有抑制之效能， 制 之效能，且隨時間之增加而有越明顯之趨勢。 In this paper, three kinds of fiber length, fiber content and water/cement ratio were used as variables to mix glass-fiber reinforced cement(GRC) by spray-up method. Then, Short-term static loads(compressive ,tensile, bending and shear strength)were applied to the specimen to investigate the primary mechanical properties. The behavior of the toughness and the drying shrinkage were found. From the results of the experiment, it is found that the best strength increase as compare with plain mortar is 1.82~3.20 times for tensile strength , 2.14~3.30 times for bending strength , 1.27 ~1.48 times for compressive strength , 1.33~1.45 times for shear strength. The unit fiber content that produce highest tensile and bending strength is 3%.Because of the fiber restrain effect, compressive strength of the specimen would changed with the loading direction. The specimen with longer fiber has higher tensile and bending strength when the fiber content is increased. However, specimens mixed with low w/c ratio , high fiber content and long fiber length, bad workability will make the GRC material porous, which will reduce its strength. GRC material has greater toughness than that of the plain mortar. The toughness index measured is between 68.9 to 98.9 when fiber content is 5%.With the decrease of w/c ratio, the GRC material has higher bending strength, but the toughness has a decreasing intent. The adding of glass fiber can reduce the drying shrinkage of the GRC material, which is more obvious with increase of time.