Study On The Low Strength Self-compacting Concrete With Limestone Powder

Since it was invented, self-compacting concrete has been attracted widespreadconcern in the world. It is considered to be one of the important direction for futuredevelopment of the world of concrete. Judging from the current situation, now most ofthe application of self-compacting concrete is basically higher strength. But the mostconcrete used in the world is lower strength concrete. In this paper, how to uselimestone powder in self-compacting concrete to make out low strength concretewhich performance can well meet the work practice requirements, are studied. First ofall, the influence of limestone powder dosage on the properties of high fluidity mortar,such as fluidity, strength and micro-structure, are studied. And then the currentself-compacting concrete mix design methods are summarized and analyzed. On thebasis of a fixed aggregate volume method, the self-compacting concrete mix designmethod based on the flow properties of mortar is discussed on.Using thisself-compacting concrete mix design method, low strength self-compacting concretewhich have40%,50%,60%limestone powder content instend of cement is make out.According to the ordinary concrete mix design method, ordinary concrete whichstrength class is C30and C40is made out. Then comparative study on the durabilityand micro-pore structure of self-compacting concrete and ordinary concrete is made.Durability test include the freeze-thaw test, carbonation test and the Chloridepenetration test. The micro-pore structure of the concrete includes the Bubble analysisof hardened concrete and the microscopic pore pressure mercury test. The resultsshow that the durability of the self-compacting concrete with low strength is betterthan that of ordinary concrete with the same level of strength.With the increase indosage of limestone powder, self-compacting concrete also shows the unique laws andphenomena.