Cracking of asphalt pavement is one of the main diseases that will be encountered in the use of asphalt pavement all over the world. The severity of cracks is different whether in frozen or non-frozen areas. The causes and forms of asphalt pavement cracks are various, but as far as the main causes of asphalt pavement cracks are concerned, cracks can be divided into two categories, namely, load-type cracks and non-load-type cracks.
Using geotechnical materials to prevent asphalt pavement cracking has obvious effect. Semi-rigid materials with good erosion resistance, small dry shrinkage and temperature shrinkage coefficients and high tensile strength are selected for the base course, and aggregates with low temperature expansion coefficient are preferred.
Select high-quality asphalt with good relaxation performance as the surface layer to ensure the penetration and ductility of asphalt; Without high-quality asphalt. Some additives or polymers should be used. So as to improve the low-temperature crack resistance and high-temperature stability of asphalt.
Before paving asphalt pavement, adopting anti-crack measures and treatment technology can greatly reduce the occurrence of pavement cracks. This kind of thinking and method emphasizes taking measures to prevent the formation of cracks in the early stage of road construction, or treating existing cracks by selecting road structure, technology or materials, so as to reduce or not appear cracks at all, or greatly reduce the original or inevitable crack activities.
Note: The vibratory roller should be rolled from low to high along the paving direction, and the rolling times of each part should be the same, and pressure leakage is not allowed. Rolling times should be appropriately increased on both sides of the road width. When rolling, you must go straight at a constant speed, and you must not change speed or stop. Under special circumstances, when parking or reversing is necessary, the vibration must be stopped first. Within the range of 4 ~ 5m at the end of the construction section, the roller should be rolled horizontally from low to high along the cross slope of the road surface to prevent cracks or looseness at the joints. Lime-water ratio, compactness and consistency are the main factors affecting the strength of RCC. The flexural strength decreases sharply with the decrease of compaction degree, and the greater the ratio of lime to water, the greater the influence of compaction degree on flexural strength. Under the same degree of compaction, the greater the ratio of lime to water, the higher the strength. Consistency is a key index that affects the compaction performance and smoothness of RCC. Too high consistency makes it difficult to compact, resulting in lower strength. If the consistency is too low, waves will easily appear when rolling, which will affect the smoothness of the road surface.