Preparation Of PVC Sheet Piles And Research On Their Aging Resistance

PVC sheet piling,as a new type of foundation pit supporting material,is expected to replace the traditional sheet piling materials such as wood,concrete,steel,because its unique advantages such as light weight with high strength,low cost,excellent corrosion resistance,etc.Such products have been researched and applied in several developed countries.However,in China the research in this area is still in its infancy.In this paper,with the aim of engineering application,we researched the mechanical properties of the prepared PVC sheet piling and evaluated the reliability of the long-term outdoor use.Through the modification of the resistance to UV aging,and structural design optimization to achieve the improvement of the PVC sheet piling’s service life.The main research contents are as the following:1)The mechanical properties of PVC sheet piling under the thermal aging and UV aging were studied.The experimental results showed that the mechanical strength and modulus of the PVC sheet piling could be stable for a long time in the aging process,while the aging had a great influence on the toughness of PVC.Increasing the thickness can apparently improve the aging resistance of the sheet piling.Take the 7mm PVC sheet piling as the research object,according to the Arrhenius equation,the service life of the sheet piling was 21.7 years when the 5%elongation at break was used as the failure critical value and the service life of the sheet piling was 5.3 years when the notched impact strength was reduced to 2KJ/m2.According to the indoor and outdoor ultraviolet radiation equivalent calculation,the service life of the sheet piling was 3.51 years when the 5%elongation at break is used as the failure critical value and the service life of the sheet piling was 17.5 years when the notched impact strength was reduced to 2KJ/m2.This indicates that PVC sheet pile can meet the requirements of long-term outdoor use.2)Modification of PVC sheet piling’s UV resistance.The effect of the UV absorber was evaluated by blending modification.Also The influence of surface polyurethane coating on the UV aging of PVC sheet was investigated.The experimental results showed that the addition of Etocrilene could effectively improve the anti-ultraviolet aging performance of PVC.While the polyurethane coating on the UV aging of PVC had a role in promoting,which was not suitable for the PVC sheet piling protection.3)Based on the data of the modified PVC sheet piling,the structure were optimized by ANSYS finite element software and the stress and deformation of the sheet piling under different working conditions were investigated.The results showed that under the top riveted condition,PVC sheet piling had the lowest tension 6.82MPa,the lowest deformation 18.44mm.Contrast with the initial PVC material,the deformation declined by 16.6%because of the modification.