Evaluation on High-temperature Adhesion Performance of Hot-applied Sealant for Asphalt Pavement

In order to investigate the high-temperature performances of the asphalt pavement hot-applied sealant, as well as to reduce failures of the sealant pullout, the softening point test and the flow test（two existing methods for evaluating high-temperature performances） were conducted. It was found that both tests could not accurately reflect the adhesion performances of the sealant at high temperatures. For this purpose, the adhesion test for PSAT（pressure sensitive adhesive tape） has been taken as a reference to develop a device that is suitable for evaluating the adhesion performances, by modifying relevant test parameters according to the road conditions at high temperatures. Thirteen common sealants were tested in the modified adhesion test, softening point test and f low test. The experimental results show that no significant correlation（p〉0.05） exists between the adhesion value, softening point, adhesion value and flow value; while a significant correlation（p〈0.05） exists between the softening point and flow value. The modified adhesion test is efficient in distinguishing the hightemperature adhesion performances of different sealants, and can be used as a standard method for evaluating such performances.

Improvement and optimization of preparation process of seedling-growing bowl tray made of paddy straw

A new type of rice seedling carrier named seedling-growing bowl tray made of paddy straw(SGBTMPS)was developed in China.Traditional preparation process for SGBTMPS is complex and difficult to operate.Hence,a new SGBTMPS preparation method has been developed by using straw powder as the main raw material.In this method,modified starch-based adhesive was replaced by the binder of thermosetting adhesive,and preparation constraints such as forming pressure,forming temperature,and dwell time were decreased.The effects of factors such as glue(modified starch-based adhesive),forming pressure,forming temperature and dwell time on SGBTMPS preparation were evaluated by single factor experiment.Orthogonal experiment and comprehensive weight analyses were adopted to optimize the parameters for SGBTMPS preparation.The results showed that optimized parameters were 125% glue and 1.2 kg mixed materials with the forming pressure,temperature,and dwell time of 30 MPa,140℃ and 330 seconds,respectively.Compared with traditional preparation process,the proportioning link,preparation link,and preparation time in the new preparation process were reduced by 66.7%,33.3%,and 17%,respectively;the pot-hole percentage and the expansion ratio were increased by 0.09% and 0.05%,respectively.This study indicated that the new preparation process for SGBTMPS was simpler and easier to operate and would provide a useful reference for further research and industrialization on SGBTMPS.