Mixed Aggregate Concrete Research On Mechanical Properties

The Combined Aggregate Concrete is a Transitional concrete which is develop from plain concrete and lightweight aggregate concrete. Compared with the lightweight aggregate concrete, Combined Aggregate Concrete have high strength to density ratio and high elastic modulus, small shrinkage and small creep deformation. Combined Aggregate reduce the density of ordinary concrete and improve the advantages of cement hydration. Currently, the research in this respect is still relatively small at home and abroad. In this paper, do the following work about the mechanical properties of combined aggregate concrete.In the experiment, according to different water-cement ratio, lightweight aggregate replacement rate,312 concrete block were made and tested cube compressive strength, axial compressive strength, cube splitting tensile strength and axial tensile strength under the age of 28 days, study the effect on the mechanical properties of combined aggregate concrete about water-cement ratio and lightweight replacement rate.The results show that:(1) The density of Combined Aggregate Concrete reduced with the increasing of light weight aggregate replacement rate, the strength of concrete have more impact on specific strength than replacement rate of mixed lightweight aggregate.(2) The compressive strength and tensile strength reduces with the increasing of light weight aggregate replacement rate and water-cement ratio(3) The ratio of Combined Aggregate Concrete cube prism compressive strength and axial compressive strength don't have much relationship to lightweight aggregate replacement rate, and the ratio is about 0.89. The ratio of Splitting tensile strength and cube compressive strength is between 1/12～1/16, The ratio of axial tensile strength and splitting tensile strength is about 0.95(4) Synthesizing the result of test in home and abroad about Combined Aggregate Concrete, based on the test,use of regression analysis and propose the formula between cube compressive strength and splitting tensile strength of the relationship:ft,s=0.3fcu2/3,and the formula between cube compressive strength and axial tensile strength of the relationship:ft=0.26cu2/3The results of this article can provide useful information for studying on the combined aggregate concrete and applying it in the future.