Study On Tension Behavior Of Waterproofing Under Sustained Load

In order to grasp the engineering properties of waterproofing, and evaluate its tensile properties, this paper carried out an experiment on PVC waterproofing which parameters included the ratio of initial elongation, environmental temperature , the time of sustained load. First of all, this study researched stress relaxation of the PVC waterproofing . To conduct regression analysis of the experimental data could set up the calculation formula of stress relaxation, using of three component model. Then to study the accuracy of the calculation formula comparing with the experimental results . Secondly, the paper proposed an experimental method that could evaluate the tensile properties of PVC waterproofing under sustained load by controlling the rate of the initial tensile. This method could evaluate systematically the tensile properties of PVC waterproofing in the different Parameters.The conclusions derived from the investigation are as follows:1) The experimental method that this paper proposed could grasp the tensile properties of PVC waterproofing under sustained load by controlling the rate of the initial tensile to simulate the cracks under the Waterproof layer in the different Parameters. such as temperatures, ultraviolet, The initial elongation rate and the load time .2) With the temperature increasing , the lossing rate of the stress also increased in the stress relaxation experiment.3) The prediction based on the three components model meet better in the late of the post-stress relaxation, but not meet accuratly in the early of the post-stress relaxation , so it is still insufficient.4) To make the middle of the original length×width×thickness (25mm×6mm×1.2mm) of the dumbbell-shaped specimen as a benchmark, could found this results . The decline in area is greater with the greater of the ratio of initial elongation; the percentage of area decreased when the specimen unloaded and then placed 24h .5) The ratio of rupture elongation of the waterproofing was greatly reduced by the initial elongation. The ratio of rupture elongation was lower when the ratio of initial elongation was greater; the length of time hold less impact of The ratio of rupture elongation ,it did not show obvious regularity.6) With the increasing of the ratio of initial elongation, the average tensile strength increased.7) The stress-strain relationship in different temperatures had no relationship with the load time. When the aging temperature is lower, the stress-strain curves had a clear point; and the aging temperature is higher, the stress-strain curves had no point.8) The availability of ultraviolet had little effect on the tensile properties of the waterproofing in the short term.