Effects Of Water Reducing Agent On Workability And Strength Of Concrete

Accompanied with the apply of Water reducing agent，concrete ushered in the newrevolution，the workability of concrete becomes more and more important.The present studieson the workability of concrete can be generalized roughly for flow method and rheometrymethod.Most of flow method are one-point，and the one-point method is not a comprehensivedescription of workability of concrete.What is more，a great quantity of test is a shockingwaste of materials and human resources. Rheometry method mostly uses self-made rheometerwhich has poor precision，and the reproducibility of experiment is bad.Rheometer AR2000ex， which is the most best stress control rheometer withhigh-precision in the world now，is used in the experiments. Based on experimental research，Studies on the effect of three kinds of water reducing agent (FDN、HW-1and HS-1)on therheological properties of cement paste and mortar and slump and strength of concrete. Theresults show that：1、Results of the experimental show that rheological curves of cement paste and mortar isvery well with the Bingham model.With the increase of water reducing agent′s proportion，the rheological parameters of cement paste and mortar gets smaller.What is more，comparesthe rheological parameters of cement paste and mortar，the result shows that，addition of fineaggregate causes the water reducing agent′s saturation-point to become larger.2、Studies on the rheological parameters of cement paste and mortar change over time，it shows that，dispersion effect of water reducing agent on cement will take a specified time.In engineering application，there should be some time to water reducing agent dispersivecement，the recommended time is about fifteen-thirty minutes.3、The three kinds of water reducing agent can improves slump of concrete，but there aredifferent. HW-1and HS-1′s proportion make the slump of concrete change more easy thanFDN′s proportion.It means that concrete′s slump improves easy with the increase of waterreducing agent′s proportion.4、Under the same water-cement ratio，strength of concrete within water reducing agentis lower than concrete′s without water reducing agent，but strength of concrete keeps constantwhen increase the water reducing agent′s proportion. What′s more，when concrete with waterreducing agent，the strength of concrete will stay about same whenever tooling in sixty minutes.