Research On Frame Theory Of Pebble Concrete

The hydrated cement paste model theory, the core of which is water-binder ratio, emphasizes the influence of water-binder ratio on the strength of concrete and neglects the coarse aggregate influence on concrete performance. Based on the hydrated cement paste model theory, and considered the influence of coarse aggregate to the concrete, Frame Concrete Model (FCM) was proposed by professor Wang. In FCM, the influence of coarse aggregate on concrete strength is emphasized, the combined effect of water-binder ratio,sand-cement ratio and sand-paste ratio on concrete performance is considered. Professor Wang and his colleagues have made a lot of research on FCM which mainly concentrated in concrete made by rubble. Based on this research, the filling and piling characteristics of pebble was studied, the method of pebble frame concrete mix proportion design was proposed, the compressive strength and durability of pebble frame concrete was studied in this article. The major content of the thesis include:1Combining the particle filling theory, the filling and piling characteristics of pebble is studied. Void fraction and equivalent coordination numbers of pebble was studied.2C20-C60pebble concrete and corresponding mortar which the maximum particle size and void fraction of pebble and the content of fly ash was different was 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.3According to the method of pebble frame concrete mix proportion design and traditional concreted mix proportion, pebble frame concrete and traditional pebble concrete was prepared. And then their mechanical property was compared. It turned out that the compressive strength of C30pebble frame concrete can achieve the preparing strength. Compared to traditional pebble concrete, pebble frame concrete consumed less cementitious materials, so the pebble frame concrete is more economy.4The paper studied the durability of pebble frame concrete by testing its carbonation resistance, sulphate corrosion resistance, frost-resistance and chlorion penetration resistance. It showed that the durability of pebble frame concrete was similar as the traditional pebble concrete and its durability can meet the provisions of the relevant standards.