Flaws in concrete Flaws are attributable to a number of causes. the main ones being: >Discontinuities in the cement paste(水泥胶体) owing to its complex morphology(形态) >Voids caused by shrinkage(徐变)，thermal movements and incomplete compaction(搅拌) Discontinuities at the boundary between aggregate(骨料)particles and the paste or nortar(砂浆)Flaws are attributable to a number of causes, the main ones being: Ø Discontinuities in the cement paste （水泥胶体） owing to its complex morphology（形态） Ø Voids caused by shrinkage（徐变） ， thermal movements and incomplete compaction (搅拌） Ø Discontinuities at the boundary between aggregate （骨料）particles and the paste or mortar （砂浆）