混凝土的收缩、开裂及其评价与防治

Shrinkage and cracking of concrete and its evaluation and prevention

长期以来 ,混凝土的收缩性质受人关注 ,但除了大坝以外 ,通常只测定混凝土的干缩值 ,并以其评定混凝土开裂的可能性。然而 ,随着对水泥与混凝土工程技术的不断研究发现 ,温度收缩和自身收缩的是引起开裂的主要原因。同时 ,由于混凝土早期强度发展加速 ,弹性模量、徐变松弛等参数随之变化 ,造成开裂趋势明显加大。因此 ,更新评价和预测混凝土收缩与开裂的方法 。

Shrinkage is a concerned property of concrete for long time.But normally only dry shrinkage is measured and with which predicts possibility of cracking except the concrete for dam construction.Since advances in cement and concrete technology and structural engineering,cracking phenomenon more and more results from thermal contract and autogenous shrinkage.At the same thime,the strength of concrete at early age increases quickly,its elastic model and creep relaxation are changed also along with,resulting remarkable trends of cracking.So it is very necessary and eagerly to update the methods of evaluating concrete shrinkage and predicting its cracking trends,and to develop the measures to improve crack resistant properties of modern concrete. 〔