20 泌水（Bleeding） 較大顆粒的骨材下方，可能由泌水作用而積水，稱為水袋 水袋中水分散失後形成孔隙，可能產生裂縫 During the placing process, the aggregates tend to settle in the form which force any free moisture to move upwards towards the top surface of the finished concrete. This effect is known as bleeding. Bleeding should be held to a minimum but needs to be sufficient to prevent plastic shrinkage cracking. Concrete in the fresh state must also be workable enough to conform to a variety of placing and finishing conditions on the job site.
23 坍度試驗- ASTM C 143；CNS 1176 坍度試驗(Slump test)ASTM C143-90a 目前世界各國使用最普遍也是最廣泛的試驗方法只適用骨材粒徑小於381mm的混凝土量測的測具主要有平截圓錐體，頂部直徑為101.6mm-ψ，高度為304.8mm。另有一支直徑16mm-ψ，長度600mm的半圓球頂搗棒
24 坍度試驗 填充混凝土至完成提起坍度錐，須在2.5分鐘內完成。量測圓錐中心坍下的垂直高度，即為坍度 The slump test does give some indication of segregation. If the slump is sheared and collapsed, rather than sagged evenly, then segregation and bleeding should be expected of the fresh concrete. The addition of more sand or cement should help provide a greater amount to consistency and cohesiveness to the mixture. Cohesiveness may wane if too much water is added to the mixture.填充混凝土至完成提起坍度錐，須在2.5分鐘內完成。量測圓錐中心坍下的垂直高度，即為坍度