Experimental Study On Vibration Mixing Roller Compacted Concrete

As a roadbed material,RCC has been widely used in road construction.In order to study the performance characteristics of RCC,many scholars have conducted in-depth research on the material characteristics,but there are very few studies based on the mixing method.Vibration mixing is a high-efficiency mixing technology,and previous studies have shown that large-amplitude vibration mixing can significantly improve the mixing effect of RCC.In order to further explore whether small-amplitude vibration mixing has the same effect on RCC,this paper studies the fresh mixing performance and hardening performance of RCC with small-amplitude vibration mixing parameters and forming weight as control variables,provide a reference for improving the mixing quality of RCC and improving the performance of concrete.In this paper,by analyzing the action mechanism of vibration mixing on roller compacted concrete,the experiment is compared with ordinary mixing and vibration acceleration with four accelerations under two amplitude conditions..At the same time,the hardening properties of RCC were studied by combining three types of forming weights.The research results show that,compared with ordinary mixing,vibration mixing can effectively improve the workability and uniformity of roller compacted concrete,and as the acceleration of vibration increases,the lifting effect increases in turn.When the vibration acceleration exceeds 4g,the lifting effect tends to be stable,and the effect of vibration mixing on the uniformity of fine aggregate in freshly mixed RCC is more obvious.Through comparative analysis,it is concluded that the mixing power of RCC is different from that of ordinary concrete.There are no characteristic points such as "viscosity point" and "flow point" during the mixing of RCC,and the mixing power remained stable after two short rises until the end of mixing.When molding with different weights,it is concluded that compared with ordinary mixing,vibration mixing can shorten the forming time of RCC and increase its strength,but shortening the forming time is not conducive to the improvement of the strength of RCC.According to the hardening performance of RCC,it was found that the 28 d compressive strength of RCC can be increased by 42.77% and the strength variation coefficient can be reduced by 68.39%.The 28 d splitting tensile strength can be increased by50.48% at the maximum,and the strength variation coefficient can be reduced by 79.07% at the maximum.The reduction of the reinforcement effect and the variation coefficient tends to be stable when the vibration acceleration exceeds 4g.By comparing the different molding weight results,it is concluded that in this test,the parameters of amplitude 1.36 mm,vibration acceleration of 4g,and molding weight 15 kg can obtain the best results.