Study On Static And Fatigue Properties Of ALWC Under Low-and High-temperature And Uniaxial Stress

All-lightweight concrete(ALWC)has good properties of lightweight and high strength,thermal insulation,seismic and fire antifreeze,which is widely used in high-rise buildings,large-span structure engineering,but the mechanical properties,thermal properties and durability of the concrete are different from that at room temperature.Also,in practical engineering,the concrete buildings not only bear static loads,but also often under fatigue loads,which will makes the structure emerge fatigue failure or dynamic failure under the condition of static strength.Taking LC30 for an example,this paper studies the static mechanical properties and fatigue properties of concrete uniaxial compression under different ambient temperatures.The main research contents are as follows:(1)The experimental studies on the mechanical properties of ALWC after different temperatures were conducted,which aims to analyze the change rules of the basic strength,elastic modulus and compressive stress-strain curves of ALWC with the changes of temperatures.In addition,the mechanism of concrete deterioration and spalling and the bursting mechanism of polypropylene fiber were discussed;(2)The experimental studies on the basic strength,elastic modulus and compressive stress-strain curves of ALWC after different temperatures and different ages were conducted,and then this paper not only analyzed the change rules of the general mechanical properties of ALWC with the changes of temperatures,but also compared the performance between ALWC,ordinary concrete and recycled concrete and discussed the strength growth mechanism of ALWC after low temperatures;(3)This paper gained S-N curves(?)-N curves of ALWC for which subjected to high temperatures and low temperatures after developed corresponding uniaxial compression fatigue tests.Compared with ordinary concrete,though the fatigue strain accords with the law of three stages,the fatigue life of ALWC is lower than ordinary concrete;(4)This paper validated the fatigue life and gained the fatigue life distribution of ALWC under different survival rates by using Weibull distribution and log-normal distribution probability theory.Last,the fatigue equations were established which were considered the failure probabilities pf.