布敦岩沥青技术要求及试验方法探讨

摘要:

简要概述了印尼布敦岩沥青(BRA)的物理化学特性,与道路石油沥青相比,BRA的溶解度低、矿物成分含量高；与热拌沥青混合料相比,BRA的沥青含量高、矿料粒径极小。由于BRA的特殊化学组成,沥青或沥青混合料的试验方法不能完全适用于BRA。分析了现行行业和部分省市标准中关于BRA的沥青含量、溶解度和灰分含量试验项目技术要求的合理性。灰分含量试验中,BRA在马弗炉中经900℃温度煅烧后,不仅其中的沥青被快速煅烧,矿物成分中的碳酸盐亦被分解逸出二氧化碳气体,质量损失远大于实际沥青含量,不可将质量损失视为沥青含量。灰分残渣的化学成分已不同于BRA中原有矿物成分。现行标准中的灰分含量技术要求上限值应调低。

Abstract:

The physical and chemical characteristics of Buton rock asphalt (BRA) are briefly introduced. In comparison with the neat bitumen, BRA has a lower solubility in trichloroethylene and higher mineral matter content; in comparison with the hot mix asphalt (HMA) mixtures, it has a higher bitumen content and much smaller aggregate size. It is shown that testing methods for bitumen or bituminous mixtures may not be suitable for BRA,as its special chemical composition. The technical requirements of bitumen content, solubility in trichloroethylene as well as ash content for BRA, listed in current specifications are analyzed. In the test for ash in BRA with a muffle furnace at 900℃, not only the bitumen is readily burned, but also the carbonate materials presented disappear in the form of carbon dioxide. Thereafter, the mass loss after burning is much greater than the bitumen content, so it may not be regarded as the bitumen content. The chemical composition of ash residue is greatly different from that of the original mineral matter in BRA. The upper limit of technical requirements for ash content in current standards should be revised lower.