Improvement in Mechanical and Workability Properties of High Performance Concrete by Manufactured Sand with Mechanism Analysis
To investigate the influencial mechanism of manufactured sand content with its component on the workability and mechanical behavior of high-performance concrete in subway engineering,this study took manufactured sand in Guangdong district as the research object.The high-performance concrete with various volumetric fractions and stone powder content of manufactured sand were proposed.The variations of manufactured sand volumetric fractions and stone powder content on the extension degree,slump,state of fresh concrete,compressive and bending strengths were studied.Furthermore,the influential mechanism of each factors on concrete behaviors were revealed in combination with the microstructure of concrete under electron microscopy.The results show that the manufactured sand concrete exhibits excellent construction performance and state,as the manufactured sand fractions and stone powder content equaling to 40%and 5%,respectively.With the increase of manufactured sand fractions,the concrete compressive and bending strengths exhibit a trend of rise first and then fall.The stone powder content has no effect on the ultimate mechanical properties of the concrete.While,with the increase of stone powder content,the concrete early strength increases significantly.Overall,it is concluded that the manufactured sand in this study can be used partially to replace natural sand,and excellent behaviors can be obtained as its volumetric fraction equaling to 40%.The proposed manufactured sand high-performance concrete exhibits outstanding workabilities and can meet corresponding construction performance and structural strength requirements.
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