The asphalt road for daily travel seems to be flat and firm, but in fact, there are many inherent shortcomings in ordinary asphalt: high temperature in summer is easy to soften and deform, rutting occurs, low temperature in winter is easy to harden and crack, long-term vehicle rolling, rain washing and sun aging, but also pit, loose, peeling and other diseases, greatly shortening the service life of the road. Asphalt modifier is the core chemical material specially used to make up for the defects of ordinary asphalt, upgrade asphalt performance and improve road quality. It is also an indispensable key auxiliary material for modern high-standard road construction. 
In short, asphalt modifier is a kind of additives that reconstruct the internal colloidal structure of asphalt through physical blending or chemical reaction. It can be mixed into high-temperature molten asphalt, and after full shearing, stirring and fusion, it can thoroughly optimize various physical properties of asphalt, make ordinary asphalt "reborn," adapt to complex road conditions and extreme weather environments, reduce pavement diseases from the root and prolong the service life of roads. 
I. Four core functions to solve common pain points on the road 
1. High temperature resistance, rutting resistance, bid farewell to summer road deformation 
Ordinary asphalt is extremely sensitive to temperature. It will soften and viscosity will decrease greatly in high temperature weather in summer. After repeated rolling by heavy vehicles, permanent deformation such as depression, rutting and displacement will easily occur on the road surface, which not only affects driving comfort, but also buries potential traffic safety hazards. 
The asphalt modifier can effectively improve the high temperature stiffness and shear modulus of asphalt, enhance the high temperature stability of asphalt, keep the asphalt compact structural strength under the scorching heat environment, and is not easy to flow and deform, fundamentally solve the problem of high temperature rutting, and perfectly adapt to the urban trunk road, expressway network, heavy load intersection and other sections with large traffic flow and high load. 
2. Low temperature resistance, crack prevention, resistance to winter road damage 
In the low-temperature environment in winter, ordinary asphalt will quickly harden, become brittle, and lose flexibility. Under the shrinkage stress caused by sudden temperature drop and the impact of vehicle rolling, horizontal and vertical cracks can easily appear on the road surface. After rainwater seeps into the subgrade along the cracks, It will further cause more serious diseases such as subgrade collapse and pavement potholes. 
The modifier can obviously improve the low-temperature toughness and elastic recovery ability of asphalt, reduce the low-temperature brittle point of asphalt, keep good expansion performance of asphalt in cold environment, effectively resist low-temperature cracking and reflection cracks, and is especially suitable for road construction and maintenance in northern alpine areas and mountainous areas. 
3. Strong bonding resists water damage and eliminates loose potholes on the road 
Ordinary asphalt and gravel aggregate adhesion is limited, encounter rain, snow melt water, moisture easy to invade the asphalt and aggregate interface, resulting in asphalt peeling, loose aggregate, over time the pavement will appear pits, particles, peeling and other problems, that is often said "water damage." 
Asphalt modifier can greatly improve the adhesive strength and waterproof performance of asphalt, strengthen the adhesion between asphalt and sandstone aggregate, firmly lock aggregate from falling off, and block moisture penetration at the same time, effectively resist the erosion of rainwater and wet environment on pavement, greatly reduce water damage, and improve the overall compactness and integrity of pavement. 
4. Anti-aging and fatigue resistance, greatly extending road life 
Ordinary asphalt exposed to natural environment for a long time, by ultraviolet radiation, oxygen oxidation, wet and dry alternation, repeated rolling fatigue of vehicles, will rapidly age and deteriorate, hardness will increase, toughness loss, pavement performance will decline year by year. 
After the modifier is added, a stable space network structure will be formed inside the asphalt, which can effectively improve the aging resistance and fatigue resistance of the asphalt, slow down the oxidation deterioration speed of the asphalt, enable the pavement to withstand the repeated load of vehicles and the erosion of natural environment for a long time, greatly reduce the frequency of road damage, prolong the service life of the road, and reduce the maintenance cost in the later period. 

II. Simple and easy-to-understand modification principle 
Ordinary asphalt itself is an unstable colloidal structure with outstanding performance. Asphalt modifiers are mostly polymer and polymer composites. After fully mixing with high temperature molten asphalt, they will reconstruct the internal structure of asphalt by physical filling, crosslinking reaction and chemical grafting, forming uniform, stable and high strength composite system. 
Different from simple material mixing, the modified asphalt will completely change the original temperature sensitivity, weak adhesion and easy aging characteristics, with high strength, high elasticity and high stability, and realize all-round upgrading of performance. 
III. Common modifier types and adaptation scenarios 
Different scenarios have different requirements for pavement performance, and the corresponding modifier types also have their own emphasis. The mainstream types are mainly divided into the following categories: 
·Polymer modifier (SBS based): currently the most widely used general modifier, comprehensive performance balance, while improving asphalt high and low temperature performance, elasticity and fatigue resistance, suitable for highways, urban expressways, airport runways and other high standard projects. 
·High viscosity modifier: mainly super adhesion and anti-scattering performance, suitable for drainage pavement, permeable pavement, ultra-thin overlay and other special pavement, can effectively solve the porous pavement aggregate shedding, seepage loss and other problems. 
Fiber modifiers: play a reinforcing, toughening, anti-crack role, further strengthen the stability of the road, often used in bridge deck pavement, heavy road sections, old road renovation projects. 
·Recycling modifier: It is mainly used for the recycling construction of old asphalt pavements. It can activate the activity of aging asphalt, restore the original properties of asphalt, realize the recycling of old materials, save energy and protect the environment, and reduce costs. 
IV. Core value of asphalt modifier 
For road engineering, the core value of asphalt modifier lies in "improving quality and reducing cost, long-term durability". In the short term, a small increase in material cost can completely solve all kinds of common problems of ordinary asphalt pavement and improve driving stability, safety and comfort; in the long run, the service life of modified asphalt pavement is longer than that of ordinary asphalt pavement by more than 30%, greatly reducing the times of road repair and renovation, and reducing the cost of manpower and material resources in later maintenance, which is the core technical means for improving the quality and efficiency of modern road engineering. 
In the final analysis, asphalt modifiers are "performance upgrades" for ordinary asphalt. Its core function is to make up for the inherent performance defects of asphalt, so that asphalt can not only withstand high temperature rolling in summer, but also withstand cold and freezing cracking in winter, resist water damage, aging resistance and fatigue resistance, comprehensively improve road quality and stability, and make our roads smoother, more durable and safer. It is an important cornerstone for the construction of modern high-quality traffic network.