混凝土新型尿素-减缩剂耦合作用机理与研发

Coupling Mechanism and Development of Novel Urea-Shrinkage Reducing Agent of Concrete

干燥收缩引起的混凝土开裂会对结构的耐久性产生不利影响。混凝土的干燥主要出现在表层部分,内部保持相对湿润状态,若能够防止表层部分的失水干燥,就可以减少因干燥收缩引起的混凝土开裂问题。研究试图在脱模后的混凝土表面涂抹尿素水溶液,来减少混凝土的干燥收缩。研究发现,表面涂抹尿素溶液的方法,不仅可以有效减少混凝土干燥收缩,还可以一定程度上提高混凝土的抗压强度。

Cracking of concrete caused by drying shrinkage adversely affects the durability of the structure.Therefore,the shrinkage re‐duction method of adding urea has not been widely used.In addition,the drying of concrete mainly occurs in the surface part,and the inte‐rior remains relatively wet.If the drying of the surface part can be prevented,the problem of concrete cracking caused by drying shrinkage can be reduced.In this research,we attempted to develop a cheaper and simpler method to apply the urea solution on the surface of con‐crete after demolding as a method to reduce drying shrinkage.As a result,it was possible to reduce drying shrinkage by spraying urea solu‐tion on the concrete surface.It was also found that applying urea solution could increase the compressive strength.