Study On Premixed Self-compacting Asphalt Concrete

As the basis for railway track, smoothness, uniformity and long-term stability of subgrade is essential to ensure the safe operation of high-speed trains. As an important part of the high-speed railway subgrade Waterproofing and Drainage System, Subgrade surface waterproof layer is important to the long-term stability and deformation of cold area of high-speed railway subgrade. According to the local environment alpine climate and the high-speed railway requirements, Southeast University proposed self-compacting asphalt concrete waterproofing layer construction technology and relevant technical standards, and successfully applied in Harbin-Qiqihar high-speed railway trial section. The results showed that self-compacting asphalt concrete waterproofing layer can meet the needs of high-speed railway subgrade enclosed water in the alpine region. In order to promote the use of self-compacting asphalt concrete waterproofing layer technology, the research group proposed construction technology of premixed self-compacting asphalt concrete. Relying on group research results, the new premixed self-compacting asphalt concrete construction technology was proposed, and to assess the long-term storage and remelting impact on concrete performance, optimize design parameters by the method of literature review, field investigation, laboratory test and numerical analysis.1.Considering the need for long-term storage and remelting, as well as the work environment of high speed railway subgrade in alpine region, this thesis argues that premixed self-compacting asphalt concrete should have good workability, water resistance, low temperature crack resistance, high temperature stability and other properties. Long-term storage and remelting on the performance of concrete should be the key issue of asphalt concrete design.2.By asphalt binder aging studies at different temperatures, asphalt mastic remelting temperature requirements are determined. Using the existing specimens from high-speed railway trial section, effects of long-term storage and remelting on properties of concrete were studied. According to technical requirements proposed by research group, remelting and long-term storage will reduce the low temperature crack resistance of concrete, and high temperature stability, waterproof and water stability of concrete still meet the design requirements. Through laboratory tests on premixed self-compacting asphalt concrete and general self-compacting asphalt concrete, performances of premixed Self-compacting asphalt concrete were verified, still meet the high-speed railway subgrade waterproof layer technical requirements, and premixed technology enhanced the stability of the various aspects of performance.3.Taking into account the difficulty of shoulder waterproof layer under its construction, and promoting the use of large-scale self-compacting asphalt concrete technology, the summer permanent deformation of asphalt concrete in full cross section was analyzed by means of the finite element analysis software (ABAQUS). The results showed that,5cm thick asphalt waterproofing layer may be applied to the regions where the highest summer temperature is below 32℃.