Evaluation of reclaimed asphalt pavement binder stiffness without extraction and recovery

A new testing procedure to estimate the low-temperature stiffness of the reclaimed asphalt pavement （RAP） binder was developed. In the testing procedure, the SuperpaveTM Bending Beam Rheometer （BBR） with special modifications and binder blending charts by Asphalt Institute were utilized. Modifications involved the development of a new kind of sample mold and different testing parameters were made to BBR testing procedure to capture the theological properties of bitumen mortars produced by mixing fresh binder with fine RAP materials or RAP aggregate. The stiffness relationship between binder and bitumen mortar was established based on the BBR test results. The blended binder stiffness in bitumen RAP mortar was estimated from the RAP mortar stiffness based on the binder-mortar relationship. And finally, the RAP binder stiffness was estimated from the blended binder and fresh binder stiffness based on the blending charts by Asphalt Institute. The results indicate that the new procedure can capture the rheological properties of bitumen mortar and can be used to estimate the low temperature stiffness of RAP binder without binder extraction and/or any chemical treatments.

Verification of Applicability of the Polyurethane Adhesive Based on Castor Oil in the Manufacture of Glued Laminated Bamboo

The current concern with the environment promotes the development of new technologies for production with use of alternative materials, from renewable resources, and changes in production processes, having as main objective the reduction of environmental impact. One of the alternatives for cleaner production is the use of castor oil derivatives instead of non-renewable sources, such as adhesives based on PVA （polyvinyl acetate）, applied in the manufacturing process of glued laminated bamboo. Based on the versatility of the bamboo laminate and the castor oil, and from the perspective of sustainability, this study aims to contribute to the application of new materials and processes, used in the manufacturing industry, by proposing the use of the polyurethane adhesive based on castor oil for glued laminated bamboo manufacturing, which can later be used in the manufacture of several products. To verify the applicability of the polyurethane adhesive based on castor oil in the glued laminated bamboo manufacture, mechanical tests of traction and shearing of the glue sheet were performed in specimens of the said material, and the results were compared with the Cascorez 2590 and Waterbond adhesives. The results showed that the polyurethane adhesive based on castor oil, in the traction test, has superior performance than the Waterbond adhesive and slightly below than the Cascorez 2590 adhesive, but in the shear test, the polyurethane adhesive based on castor oil presented a slightly inferior performance than the other two adhesives used in the comparison.

虚化与再嵌入:数字时代新闻中的“空间”重建

数字时代,市场化和技术发展让足不出户做新闻、足不出户看新闻成为新常态。新闻事件发生的“空间”与媒体、受众所处的“地点”分离开,呈现出吉登斯所谓“空间虚化”的状态。脱域的新闻报道实现了“空间的再嵌入”,这种“再嵌入”具体表现为远程报道常规和非本地新闻的兴起。远程报道的方式把地方与熟悉性分割开来,媒体对事实的掌控度降低,导致新闻的不确定性增加。非本地新闻让受众知晓几千里外发生事件的“可见外表”,但对所处地的新变动却感到陌生。过度追逐和倚重二者会导致媒体陷入过分追求经济效益的争议,损害媒体公共性和公信力。因此媒体需要重新审视生产常规和内容选择,重申“在场”的价值,并扎根、关注本地,重建新闻的在地性,实现新闻中的空间与地方的再粘合。