Semi-rigid base asphalt pavement is a typical pavement structure in China.，Improve the quality of the functional layer of the pavement by improving，Maintain driving safety、Comfort and reliability of road structure，It is the main content of road maintenance and production at this stage.。It is gratifying that the technology of cold-mixed and cold-paved pavement materials has developed rapidly.，Such as：Fog seal、Fine anti-slip protective layer、Micro-surfacing、Functionalized composite seal、Innovative technologies such as long fiber anti-cracking composite seal and modified pavement layer of asphalt concrete pavement emerge as the times require.，The technology of pavement functional layer has entered a new stage of renewal.，Its thickness varies from 0.—60mm，Functional directional combination design can be realized as required，It fully reflects the high quality of the new productivity of the highway maintenance industry.、Efficient、Green、The great advantage of the economy。

Apparently，The mainstream development direction in the field of hot mix asphalt concrete pavement and highway maintenance technology has gradually gone away.，The reason is that the hot mix and hot laying technology itself is difficult to overcome compared with the cold mix and cold laying technology.：

1

Processing of materials from the mixing plant、Materials are transported to the place where they are paved, rolled and formed，Hot-mix hot-lay technology consistently exhibits high consumption、High pollution、Features of high configuration，In the country on the vigorous development of low-carbon、Environmental protection、Save、Under the new situation of safe production，Compared with cold mixing and cold laying series technology, it has more scientific and reasonable development advantages.。

2

On the premise of reasonable grading，The minimum paving process thickness of hot mix asphalt concrete surface course is 30㎜，Difficult to meet both dense and waterproof、Skid resistance、Anti-crack and other multi-functional requirements。If this pavement layer is added to the original pavement，Not only is the gradation irrationality caused by the superposition of the old and new surface layers，At the same time, the elevation of the pavement will inevitably lead to overpass bridges.、Tunnel、Guardrail、Bridge deck、Contradiction between clearance and elevation difference of various structures such as road edges。If the embedded milling paving is used, the project cost and solid waste will be greatly increased.。Of course, reduce the particle size of the mixture，For example, the use of tar sands can effectively reduce the thickness of the hot paving process.，But if it is used for high-grade pavement,，The hidden danger of anti-skid safety will be incalculable.。
The minimum process thickness for the cold mix and cold lay technique is zero，Under the support of the new technology of material compounding and additional function compounding,，8—15㎜It can establish excellent multiple combination design according to the requirements of multiple functions.，It can even increase the tensile strength of pavement materials by tens of times.，Meet the needs of road maintenance projects to a greater extent。

3

Cold mix and cold paving material is a kind of composite cementitious material，Also calledMOHMaterial，The material modulus can be designed and adjusted according to engineering requirements.，Especially, its high temperature stability is far better than that of hot mix asphalt concrete.。MOHThe good workability of materials has contributed to a variety of new construction methods.，Uch as micro-surfacing、Composite functional layer and modified pavement layer.，Can be well combine with asphalt pavement and cement concrete pavement，This is beyond the traditional hot mixing and hot laying technology.。

4

In the recycling of pavement materials，Hot mix and hot spread technology is even more dwarfed.，Because that recycle pavement material is already coated with the asphalt bind.，Thermodynamic too will cause the old asphalt film to scorch or even burn.，If the thermodynamic force is too small, it cannot be heated effectively.，It often causes the low temperature of pavement forming.，The compactness is not up to the standard，It even leads to serious diseases such as lack of waterproofness or loose pavement.。
Modified pavement technology of asphalt concrete pavement is the result of the development of dispersion and homogenization technology at room temperature.，The recycling rate can reach 100 percent％，Is to achieve the reconstruction of mechanical properties.MOHComprehensive technology of new composite cementitious material，Its rationality and advancement have been fully reflected in the application engineering.。

　　The author believes that，The construction of hot-mixed and hot-paved asphalt pavement is still in the absolute dominant position in the new pavement engineering.，In the field of highway maintenance engineering, the technology of cold mix and cold pavement functional layer has achieved a leap-forward development of renewal.，The above views are for reference and exchange of colleagues in the industry.，Criticism and discussion are welcome.。