论文部分内容阅读
一、干缩造成表面裂缝的控制混凝土施工中干缩造成的裂缝为表面性的,宽度多在0．05～0．2mm之间,其走向没有规律。干缩裂缝产生的原因主要是混凝土成型后养护不当,表面水分散失过快,造成混凝土内外的不均匀收缩,引起混凝土表面开裂,含泥量大、粉细砂配制的混凝土,也容易出现表面干缩裂缝,应采取以下控制措施:掺入粉煤灰降低混凝土的泌水和收缩值;选择收缩值较小的水泥;在满足混凝土强度情况下尽量减少单位水泥用量;选择含泥量较小的中(粗)砂。
First, the shrinkage caused by surface cracks in the control of cracks in the construction of concrete cracks caused by the surface of the width of more than 0.05 ~ 0.2mm, the trend is not regular. Dry shrinkage cracks are mainly due to improper maintenance after forming the concrete surface water loss too fast, resulting in uneven internal and external shrinkage of concrete, causing the concrete surface cracking, clay content, fine sand powder prepared concrete, but also prone to dry surface Shrinkage cracks, should take the following control measures: Addition of fly ash to reduce the bleeding and shrinkage of concrete; choose a smaller value of the contraction of the cement; Concrete strength to meet the minimum requirements to reduce the amount of cement; Select a smaller amount of mud Coarse sand.