Low-temperature crack resistance refers to the performance of an asphalt mixture that does not appear to have low-temperature embrittlement, low-temperature shrinkage cracking, temperature fatigue, etc., resulting in low-temperature cracks. The main factors affecting the low-temperature cracking resistance of asphalt mixture are material properties such as asphalt temperature sensitivity, time sensitivity, aging performance, etc., pavement structure geometric dimensions such as surface layer thickness, etc., temperature and other environmental factors such as temperature difference.
Measures to Improve Low-Temperature Crack Resistance of Asphalt Mixture The low-temperature deformation capacity of concrete depends to a large extent on the low-temperature properties of asphalt materials, the bond strength between asphalt and mineral aggregates, the type of gradation, and the uniformity of asphalt mixture. It should be considered from two aspects of design and construction.
1. Design aspects:
1) When designing a semi-rigid pavement, first of all, semi-rigid materials with good erosion resistance, small drying and temperature shrinkage coefficients, and high tensile strength should be selected as the base layer.
2) Select high-quality asphalt with good relaxation performance as the asphalt surface layer. In the absence of high-quality asphalt, measures should be taken to improve its properties of asphalt.
3) In order to further improve the temperature crack resistance of the surface layer, rubber asphalt or polymer asphalt can be used as a seal layer on the asphalt concrete surface.
4) Set up an intermediate layer for stress relief.
1) Strictly control the water content during the rolling of the semi-rigid base course, which cannot exceed the optimal water content required for compaction or be controlled within the allowable range of the construction specification.
2) Emulsified asphalt should be used as a penetration layer or seal layer immediately after the semi-rigid base layer is rolled or at the latest after the curing.
3) After the permeable layer or sticky layer is completed, the asphalt surface layer should be paved as soon as possible.