Study On Rubber Power Modified Recycled Aggregate Concrete

Recycled concrete refers to waste concrete blocks after crushing, gradation andaccording to a certain proportion, instead of sand and so on all or part of the naturalaggregate into the new concrete. The study on RAC can reduce the pollution of theenvironment and resources exploitation. At the same time, the number of discarded tiresincrease amazing because of the development of the car industry produced each year, itis difficult to deal with, landfill or burned can cause environmental pollution. Applicationthe rubber powder which is made from discarded tires to improve RAC durabilitydeficiency, will further reduce the environment pollution, to achieve the rationalutilization of resources.Subject is divided into two parts, the first part based on orthogonal test, study on theinfluence degree of water cement ratio, rubber powder content; recycled aggregatescontent; fly ash and slag content and different RA process to RAC workability and themechanical performance. The results show that, water-cement ratio effect obviously onthe compressive strength of RAC. When the water-cement ratio is constant, rubberpowder content is significantly affected on the compressive strength of concrete.The second part research on the frost resistance of concrete with0.45water-cementratio and different recycled aggregate replacement proportions was studied in the waterand3.5%sodium chloride solution. The mass proportions of recycled aggregate are25%,50%and75%, respectively. Furthermore, the frost resistance of the modified concretewith5%and10%rubber powder volume fractions replacing fine aggregates was studied.Application of ultrasonic detector tests the innner of concrete damage evolution, andthrough the quality loss reaction concrete external damage status. The results show that:the frost resistance of concrete decreases with the increase of recycled aggregate; whenthe recycled aggregate mass fractions are25%and50%, its influence on the frostresistance of concrete is little, and mixing rubber powders can effectively improve thefrost resistance of concrete; when the recycled aggregate mass fraction reaches75%, itseffect on the frost resistance of concrete is significant, and mixing rubber powders has certain improvement effect, but compared with the benchmark group of concrete the frostresistance still declines sharply. The maximum freeze-thaw cycles decreases more than30%. In water frozen test, the weight loss is small and the relative dynamic elasticmodulus loss is quite obvious, so the relative dynamic elastic modulus loss is the maincharacteristic and serves as damage index. In this case, the frost resistance is better whenadding5%volume fraction of rubber powders. In salt frozen test, the main characteristicis the weight loss exceeds the requirements. The frost resistance is better when adding10%volume fraction of rubber powders. The subject provides a certain value of theapplication of RAC in the country.