Research On The Influence Of Mechanics And Durability Of Natural Lightweight Aggregate Concrete By Limestone

Natural pumice lightweight aggregate concrete have advantages on high strength with lightweight, aseismatic performance, crack resistance and fire resistance. It has become more and more sophisticated that make research of lightweight aggregate at home and abroad, it also has been used more and more widely in engineering. But it is urgency to solve that look for the suitable admixture along with the increasing demand for mineral mixture of concrete and sand resources. Limestone powder is a waste in the production process of coarse aggregate and fine aggregate? if it is discarded arbitrarily, not only the environment pollution but also a waste of resources. So it can alleviate the real problem that the shortage of common admixtures and the rising price effectively when limestone powder used as mineral admixture, and reduce the environmental pressure.The paper mix new lightweight aggregate concrete that makes 0%,10%,20%,30%, 40%,50% limestone power instead of the same amount of sand respectively.It has a research on the compressive strength of lightweight aggregate concrete under the content of different lime stone powder on 3d,7d,14d,28d,60d,90d and 120d and the tensile strength on 7d,14d,28d,60d.It finds that 30% is the best adding quantity of limestone after comparing the test results limestone powder and At the same time, we analysis the microstructure of the specimen by means of SEM to study the influence fatherly on the internal structure of lightweight aggregate concrete which mix limestone powder, besides discuss the mechanism when they are destroyed.In addition, the paper has a test on the mass loss and dynamic modulus of elasticity after 25 times,50 times,75 times,100 times,123 times,150 times,175 times,200 times, 225 times and 250 times circulation by quick freezing method, In order to have an influence on frost resistance of lightweight aggregate concrete by limestone powder. Then the microscopic mechanism of each group specimens are analyzed by the SEM after frozen thawed It finds that it is very unfavorable to frost resistance of lightweight aggregate concrete if add too much lime stone powder and the content of about 30% is better. According to the principle of ultrasonic flaw detection, testing the time and wave velocity to establish the time-distance graph. Compared to the calculated thickness of damage layer, it finds that damage layer thickness of the best group adding 30% and reference group is smaller. The other groups were seriously damaged.