Experimental Research On Bearing Capacity Of Inclined Section Of Ceramsite Concrete Beams

The numerous datum have shown that, the lightweight aggregate concrete has many advantages and prospects in engineering applications compared with the ordinary concrete. However, the technical specification for lightweight aggregate concrete structures in China has not been perfect yet,we lack strong technical support for practical engineering applications. In this paper, through the comprehensive study on the shear performance of 12 reinforced Changsha shale ceramsite concrete beams, the law of their ultimate shear capacity, diagonal cracking load, the stirrup stress's distribution, the development of inclined cracks and destructive characteristic on the shale ceramic concrete beams are thoroughly discussed. The main aspects and results of our research are given as following:1. Based on the experiment studies, the stirrup does not assume the significant tensile stress before the official formation of inclined cracks, cross-section shear is borne mainly by the stirrup after incline cracks for the stress redistribution in the inclined cracks cross-section.2. As the determination of the diagonal cracking load of the beam,for the ventral shear crack model, the external load when the ventral shear cracks appears is seen as the diagonal cracking load; for the flexure-shear crack model, based on the test observations and the Shear-stirrup stress diagram reference to the experiment, the diagonal cracking load is identified.3. The test researches show that, the stirrups in the middle part of shear zone, w-hich corresponds to the widest crack, take the highest stress. For the same shear span ratio but different stirrup ratio beams,the distribution are almost the same. The distributions are all low-high-low parabolic.But for the beams with higher stirrup ratio, the distributions are always gently, with more uniform cracks.4. Caused of the less modulus of elasticity and tensility, all the experimental beams have relative lower cracking loads. The shear cracks appear at almost the same time.5. The width of inclined crack is mainly influenced by the destructive characteristics, stirrup ratio and shear-span ratio.6. The application of the equations which are supplied by《Technical specifica- tion for lightweight aggregate concrete structures》JGJ12-2006 on the ultimoate limit of shear stress along the inclined sections in the ceramisite aggregate concrete is well confirmed through the datum of experiments and the nonlinear analysis by AN-SYS.7. From the mathematical regression, the equations on the inclined cracking loads and largest width of cracks for the ceramsite aggregate concrete are illustrated.In a word, the paper has theoretical significance for the scientific research on the bending characteristics of the ceramsite aggregate concrete beam, provides a theore- tical basis for the wide applications of the ceramic concrete.