C60低收缩徐变高性能混凝土的配制与试验研究

Preparation and Experimental Study of C60 High Performance Concrete with Low Shrinkage and Creep

为配制出适用于大跨度桥梁工程的高性能混凝土,通过掺加大掺量优质的粉煤灰、矿粉,降低水胶比的方法,进行C60低收缩徐变高性能混凝土的配制与试验研究。试验结果表明：采用优化设计混凝土配合比配制出的混凝土拌合物出机坍落度为170~215mm,2h坍落度损失较小,压力泌水率较低,表现出良好的工作性能;混凝土28d抗压强度较高,达到C60强度等级;掺加矿物掺合料的混凝土具有较低的收缩和徐变,与不掺矿物掺合料的混凝土相比,长龄期（360d）的收缩和徐变值降低了30%~50%;通过掺加大掺量矿物掺合料、降低水胶比的方法可以配制出C60低收缩徐变的高性能混凝土,该混凝土可用于塔柱和预应力混凝土箱梁中。

To prepare high performance concrete applicable to longspan bridge projects ,the C60 high performance concrete with low shrinkage and creep was prepared by adding high fly ash content concrete ,mineral powder and reducing the watercement ratio .And the relating experimental tests were conducted .The results of the study demonstrate that the slump of the concrete mixture prepared in accordance with the optimized concrete mix proportion just coming out the mixer is 170 - 215 mm . T he 2 h aging concrete show s no distinctive slump loss , the pressure bleeding rate is low ,exhibiting excellent workability .The concrete of 28 d curing period has higher compressive strength ,reaching C60 strength grade .The concrete added with mineral admixtures has lower shrinkage and creep ,compared with the concrete without mineral admixtures ,the shrinkage and creep values of the concrete of long curing period （360 d ） reduces about 30% -50% .By adding a large amount of mineral admixtures and reducing the watercement ratio ,the C60 high performance concrete featuring low shrinkage and creep can be made .T his kind of concrete is applicable to tower/pylon columns and prestressed concrete box girder .