| Lightweight aggregate concrete had significant difference with ordinary concrete, such as the composition of materials, mechanical properties and so on, as a multi-functional, sustainable development of new building materials. And its performance depended to some extent on factors within the aggregate. In this paper, the aggregate rate and size distribution of pumice light-weight aggregate was analyzed statistically by using the fractal theory to connect the material microstructure and macroscopic properties, and experimental study on mechanical properties of concrete with aggregate gradations of different fractal dimension, draw the following conclusions:(1) The Study had shown that t pumice lightweight aggregate rate and size distribution of pumice have obvious fractal phenomena, both fractal dimension of size distribution and fractal dimension of aggregate rate are between 2 and 3. Pumice lightweight aggregate size the greater the fractal dimension, the more the number of particles, the greater the degree of aggregate crushing, directly reflecting the quantitative extent of broken pumice. Fractal dimension of aggregate rate of 2.5 at about was a better aggregate gradation.(2) With the changes in fractal dimension of aggregate rate, the cube compressive strength, axial compressive strength and elastic modulus had similar scale curve, showing that rise and fall above paragraph.(3) Fitting out the relationship of the ordinary lightweight aggregate concrete elastic modulus and strength; the relationship of axial compressive strength and cube compressive strength .It had a practical significance of the study on lightweight aggregate concrete.(4) Cube specimens were crack-like damage resistance, cracks and angular department emerged numerous concrete spalling. axial compression damage was single specimen shear damage, both showing obviously brittle. Aggregate damage was a prominent feature of its damage.
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