What is Asphalt Concrete
Commonly known as asphalt concrete, asphalt concrete (bituminous concrete) is the artificial selection has certain gradation of mineral aggregate (gravel or ore crushing, stone chips or sand, gravel, etc.) and a certain proportion of road asphalt material, under the condition of strictly controlling mixing of mixture.
Asphalt concrete Soil can be divided by different binder that petroleum pitch and coal tar the two kinds of ;In some countries or regions have adopted or mixed with natural asphalt mixing.
According to the different varieties of aggregate used, can be divided into rubble, gravel, sand, slag, several classes, by using the most common debris.According to the maximum particle size mixture is different, can be divided into coarse (under 35 ~ 40 mm), medium grained (below 20 ~ 25 mm), fine grained (below 10 ~ 15 mm), sand (below 5 ~ 7 mm) for class.
At different levels according to the mixture of solid, can be divided into dense gradation, half gradation and open the number of classes, such as grading grading open also calls the asphalt macadam mixture.One of the hot mix hot shop dense gradation gravel mixture durability, high strength, good integrity, is the surface of typical road building high-grade material, the most widely used.
For asphalt concrete made with different specifications, China formulated spread hot hot mix asphalt mixture of technical specification, with porosity 10% and below is known as the asphalt concrete, and subdivided into Ⅰ and Ⅱ, Ⅰ type of porosity is 3 (or 2) ~ 6%, belong to the classification of the matches;Ⅱ type for 6 ~ 10%, belong to half level matches;Void fraction of 10% above is called asphalt macadam, open level matches;Mixture of physical and mechanical indexes such as stability, flow value and porosity.