Abstract:

Concrete samples were prepared by partially replacing cement with fly ash microbeads at weight ratio of 10%，20% and 30%，and then the compressive strength，elastic modulus and creep of the concrete samples were tested.At the same time，the microstructure of the samples was studied by the mercury intrusion porosity test.The results showed that the fly ash microbeads would reduce the early age compressive strength and elastic modulus of concrete，but it showed significant promoting effect on the long-term strength growth and elastic modulus growth of concrete.At 90 d，the sample with fly ash microbead substitution ratio of 20% had the highest strength and elastic modulus.Adding 20% fly ash microbeads could reduce the specific creep of concrete，but too much fly ash microbeads would increase the creep deformation of concrete.The pore analysis results showed that when the total pore volume was higher，the strength was low and the creep deformation of concrete was large.The addition of 20% fly ash microbeads would reduce the mesopore，macropore and total pore volume of concrete，thereby improving the strength and creep characteristics of concrete.

Key words: concrete, fly ash microbeads, compressive strength, elastic modulus, creep, pore characteristics