| Elastomer modified asphalts waterproof roll has been used more and more widely in roofing waterproof project for the excellent high temperature stability and low temperature crack resistance. However, elastomer modified asphalts waterproof roll will lose its effectiveness after by light, heat and oxygen in using process, which may shorten the service life of waterproof roll. Therefore, it is very important for extending the service life to improve the aging resistance of elastomer modified asphalts and coating.In this paper, the effects of layered double hydroxides(LDHs)/elastomer modified asphalts on preparing conditions and materials composition designing were investigated, and LDHs/elastomer modified asphalts and coating were carried out ultraviolet aging and thermal oxidative ageing test. The chemical structures and microscopic appearance of elastomer modified asphalts before and after aging were evaluated by Fourier Transform Infrared Spectroscopy (FTIR) and light microscopy. The results obtained are as follows:(1) The appropriate preparing conditions of LDHs/elastomer modified asphalts were obtained as follows:LDHs was added in the molten matrix asphalt, using high shear emulsifying machine to stir for1h, then mixed with SBS and assistant, and continue to stir for3h at180℃by high shear force device.(2) Different matrix asphalts were modified by different types of SBS to make the softening point and low temperature flexibility of the preparation of elastomer modified asphalts can reach GB/T26528-2011technical index. The addition of LDHs increases the softening point and improves the thermostability of elastomer modified asphalt.(3) After ultraviolet aging and thermal oxidative aging test, the results indicated that the aging resistance of elastomer modified asphalts could be improved obviously by LDHs. Compared with elastomer modified asphalts without LDHs, the variable quantity of softening point and low temperature flexibility were decreased remarkably after ultraviolet aging and thermal oxidative ageing, which means LDHs/elastomer modified asphalts had better original resistance. Compared with Zn-Al LDHs, Mg-Al LDHs had greater effects in improving the ultraviolet aging resistance of elastomer modified asphalts, while the thermal oxidative ageing resistance of Zn-Al LDHs/elastomer modified asphalts were much better.(4) FTIR spectrums showed that the changes in intensity of the C=O、S=O and C=C characteristic peak of LDHs/elastomer modified asphalts were less than that of ordinary elastomer modified asphalts, indicating that LDHs can efficiently reduce the ageing sensitive degree of elastomer modified asphalts. The morphology observation also indicated LDHs could retard the degradation of SBS in ageing process of elastomer modified asphalts.(5) The studies of the physical properties and aging properties of LDHs/elastomer modified asphalts coating showed that LDHs could improve the thermostability of elastomer modified asphalts coating at some degree, and had more obvious effects in improving the aging resistance of elastomer modified asphalts coating. Compared with elastomer modified asphalts coating with talc powder, the effects of LDHs on the aging resistance of elastomer modified asphalts coating with coal ash were more evident. |
PDF Full Text Request