Forecasting Of Lithium-slag High-performance Concrete Strength And Ring Method Test On Its Early-age Anti-crack Capability

Early shrinkage cracking of high performance concrete is a current hotspot of research at home and abroad.In order to make full use of local lithium-slag resources in Xinjiang,We use lithium slag as admixture of concrete kto research its the mechanical properties under low water binder ratio.First,we made concrete with lithium-slag under the premise of the same water binder ratio and the same dosage of lithium-slag and optimize lithium slag of surface area 950m2/kg which are large Contribution to the strength by test. On this basis,we analyze the concrete strength characteristics in the case that the water binder ratio are 0.4,0.35,0.3,0.27and lithium slag are15%,20%,25%,30%,35% and 45% respectively,and seek out the most economical lithium slag content.we have a more accurate prediction of concrete compressive strength by artificial neural network with the above experimental data,which provides technical support for optimizing mix of laboratory.Ring method test the influence of the dosage of lithium slag on its early-age anti-crak capability of concrete under the conditions of the same surface area (950m2/kg) and water binder ratio(0.27).We have obtained the best dosages of lithium slag which can resist early-age craking of concrete by monitoring concrete strain and observating concrete cracks. Good engineering prooerties of Lithium slag concrete has been verified by the pilot test at last.The research shows:(1)with the increase of surface area of lithium slag,the compressive strength of concrete increase under the conditions of the same water binder ratio and the dosage of lithium slag;After more than surface 950m2/kg,the growth rate trend of concrete compressive strength of different ages is slower.(2)The main facters affecting concrete strength:water binder ratio,the dosages of lithium slag,ages of concrete. With the decrease of water binder ratio,the concrete compressive strength in the same ages increase. Especially,when the water-binder ratio reached at 0.27, the changes is obviously.(3)Under the same conditions,the lithium slag dosages30% of concrete compressive strength of the ages of 28days and 90days are greater than the dosages30%. In contrast,the 28days compressive strength of the lithiumslag dosages of 35%,45% are lower. Therefore,the lithium slag dosages of 30% is more economical for concrete compressive strength.(4)With low water-binder ratio and proper super water reducing agent and control of slag content of lithium,making different strength grading high performanceconcrete which meet the requires of engineering. Although strength was low in the early period, the intensity became stronger later. It indicated that filling of the micro collection materials about lithium slag was more significant,and the hydrating performed obviously for the compressive strength in the later period.(5)With the increase of the dosages of lithium slag,the crack width and numbers of specimens significantly reduced, and the maximum width of crack significantly decrease.But,after the lithium slag dosages of 30%,the maximum width of crack of concrete increase.Therefore, the 30%dosages of lithium slag is the best for early-age anti-crack capability of concrete.