Research On Frame Theory Of Broken Pebble Concrete

The traditional hydrated cement paste model is centered on water binder ratio, so that it emphasizes the significance of that ration upon the concrete strength. However, it hasn’t proposed whether the coarse aggregate has an effect on concrete. Based on the hydrated cement paste model theory, the Frame Concrete Model (FCM) takes the influence of coarse aggregate to the concrete into full consideration. This model emphasizes the effect of coarse aggregate on the strength of concrete, as well as the influence of water binder ratio, sand cement ratio, sand-paste ratio on performance of concrete. The previous research is mainly from the crushed stone concrete. However, in recent years, as the increasing crusaded stone is being explored and used, many regions is lacked of it. Besides, longer distance transportation makes higher costs, which reduce its economy. Professor Wang and the research group mainly focus on the concrete made by rubble. Also, Liu Sha, a member in the same group, does a lot of research on the filling and piling characteristics of pebble. As a result, she puts forward the pebble frame concrete mix proportion design, as well as the compressive strength and durability of pebble frame concrete. Crushed pebble has dual advantages of gravel and artificial gravel, not only improve the physical index of the concrete, but the endurance. The major content of the thesis include:1. It studies the material characteristics of broken pebble. The study puts forward the surface characteristics of broken pebble in single particle size, and the feature and index of it as well as Fuller system graded broken pebble, including bulk density, void fraction, equivalent coordination number, elongated index, and crushed index. The selection of the parameters of the crushed pebble concrete is provided. C20-C60 pebble concrete and corresponding mortar which the maximum particle size and void fraction of pebble are different have been prepared. Then the compressive strength of concrete and mortar was achieved. According to fcu= pgfm+(1-pg)fg, the frame effect of pebble was calculated in common concrete. The function relationship between compressive strength of mortar and sand-cement ratio was established. At the same time, the function relationship between concrete compressive strength and mortar-paste ratio deviation was established. And then the method of pebble frame concrete mix proportion design was proposed.2. According to the structure of the broken cobble concrete mix design and the general method of concrete mix design, it prepares the broken pebble and ordinary gravel concrete at the strength grade of C20-C60. After testing the strength, and then making a comparison, the result shows that structural concrete has obvious advantages in low intensity region and economic performance.3 According to the structure of the broken cobble concrete mix design and the general method of concrete mix design, it prepares the broken pebble and ordinary gravel concrete at the strength grade of C20～C60. After testing the strength, and then making a comparison, the result shows that structural concrete has obvious advantages in low intensity region and economic performance.4 This paper studies the carbonation resistance, frost-resistance, and chloride ion permeability resistance of concrete. And then, compared with ordinary crushed pebble concrete, it shows that its durability can meet the provisions of the relevant standards.