Experimental Study On The Flexural Performance Of Steel Fiber High-strength Ceramsite Concrete Beams

The application of ceramsite concrete could significantly reduce the weight of the structure. With excellent tensile strength, shear strength and crack resistance, steel fiber could obviously improve the brittleness of ceramsite concrete and reduce its segregation. As an excellent building material combining the advantage of both steel fiber concrete and ceramsite concrete, steel fiber high-strength ceramsite concrete has broad application prospect in many construction projects, such as super high-rise building, subsea tunnel and cross sea bridge. However, the theory research on steel fiber high-strength ceramsite concrete is much less mature than that on reinforced concrete. Further studies on steel fiber high-strength ceramsite concrete structural component are required.By analyzing the damage mechanism, the load bearing characteristics and the failure modes of 9 steel fiber high-strength ceramsite concrete beams, this paper discussed the influence of steel fiber’s volume ratio, longitudinal reinforcement ratio and steel fiber’s length to diameter ratio on flexural performance of the beams. The following conclusions are indicated by the test result:(1) All the 9 test beams experienced ductile failure. The carrying capacity of ceramsite concrete beams and common concrete beams is roughly the same. The carrying capacity would rise with the increase of steel fiber’s volume ratio, longitudinal reinforcement ratio and steel fiber’s length to diameter ratio. The carrying capacity can be increased up to 19.7% when the steel fiber’s volume ratio is 1.5%.(2) The ductility factor would increase with the increase of steel fiber’s volume ratio and steel fiber’s length to diameter ratio, but would decrease with the increase of longitudinal reinforcement ratio.(3) The cracking load and ultimate load of the test beams would raise up with the increase of the three parameters above.The paper also provided the formula to calculate the normal section bearing capacity of the test beams, and the cracking moment was analyzed by the stress-strain relation and the ductility factor. By the regression of test data, the steel fiber’saverage influence coefficient to the crack width of the ceramsite concrete beam was carried out. the formula to calculate the cracking load and the maximum crack width under the short term load.