Experimental research on the bond-slip behavior of circular steel tubes filled with red mud concrete

Abstract：Fifteen short column circular steel tubes filled with red mud concrete were designed for the push-out test to study the bond slip behavior of red mud concrete-filled circular steel stubs, taking into account the four variable parameters including replacement rate of red mud mass, concrete strength, length diameter ratio (embedment length) , and length-diameter ratio.The load-slip curves of circular red mud concrete-filled steel tubes were obtained and the influence of the variable parameters were analyzed.The results showed that the load slip curves of red mud concrete filled circular steel tubes went through three stages:no slipping section, ascending section, descending section.The bond ultimate load increased first and then decreased with the rise of red mud substitution rate.When the substitution rate of red mud was 5%, it reached the maximum load.When the substitution rate of red mud was 20%, the bond ultimate load was equivalent to normal concrete-filled steel tube.The bond ultimate load increased with the rise of the concrete strength and length-diameter ratio, and decreased with the increase of the width-thickness ratio.

Keyword：red mud concrete-filled circular steel tubes;push-out test;bond-slip;red mud replacement rate;bond strength;