How is Asphalt Made? The composition of asphalt includes bitumen, sand, types of crushed stone or gravel, as well as mineral additives and fillers. Bitumen remains the only unchanged component, and the rest of the components can be added in different proportions.
The sand contained in the asphalt composition acts as a filler and a fine base, contributing to the distribution of pressure from the road to the ground. Without sand, the bituminous binder would flow out, and the crushed stone would be squeezed up.
In the case of special asphalts containing cement, the sand takes part in the carburizing process and gives the surface additional hardness.
Mineral filler - is a rock crushed to a dusty state (sandstone, limestone, or chalk), designed to fill the residual voids. Sandstone is the most versatile, as it is inert to almost any chemical attack. Calcium carbonates (limestone and chalk) are commonly used on public roads, while sandstone can be used near chemical plants.
Rubber - added to asphalt in the form of crumb rubber (1-1.5 mm), gives the coating high water resistance and plasticity. Asphalt treated with rubber is much less likely to crack, which increases the period between repairs. The disadvantage of such roads is their high cost, so their use is limited to laying the most critical sections of highways.
The basis of any asphalt production is the preparation of the initial components, mixing at high temperatures, and storage in special heated silos.
When laying roads, it is important that the plant is located close to the construction site since the material must be transported for laying in a heated state. If the mixture cools, it will be very difficult to tamp it, and the resulting coating will not be strong enough. Consider the stages of asphalt production.
This includes drying and sieving. Sand, crushed stone, and rock usually enter the plant in a wet or air-dry state. The presence of residual moisture is fraught with a decrease in the strength of the coating and spraying of a hot bitumen mixture when water gets into it.
To eliminate possible consequences, the material is dried at a temperature of 150-160? C - this temperature allows you to get rid of the moisture adsorbed in the pores of the material.
Sifting of crushed stone is carried out using a screen. The mineral filler is pre-crushed in a crusher, after which it is also subjected to fractionation. Depending on the production technology, drying can be single or double, repeated after crushing or sieving.
Crushed stone and sand are fed to a belt conveyor that transports them to a common hopper. Mixing with filler and bitumen can occur simultaneously or be carried out after reaching a homogeneous crushed stone-sand mass.
After adding bitumen, the temperature is maintained at 160-170? С. After reaching the required consistency, the mixture (already asphalt) enters the storage bin, where it can remain heated for up to 4 days. During this period, it must be shipped to the consumer in order to avoid loss of strength characteristics.
Modification of the asphalt with additives that impart useful performance properties is carried out simultaneously with the mixing of the asphalt. When creating a rubber-asphalt mixture, rubber crumb is added to a heated, ready-to-use product.
|Cedar Hill||Cedar Park||Channelview|
|Edinburg||El Campo||El Paso|
|Fate||Flower Mound||Forest Hill|
|Forney||Fort Hood||Fort Worth|
|Glenn Heights||Grand Prairie||Grapevine|
|Haltom City||Harker Heights||Harlingen|
|Anthem||Apache Junction||Arizona City|
|Camp Verde||Casa Grande||Casas Adobes|
|Catalina Foothills||Chandler||Chino Valley|
|Drexel Heights||El Mirage||Eloy|
|Fort Mohave||Fortuna Foothills||Fountain Hills|
|Kingman||Lake Havasu City||Marana|
|Maricopa||Mesa||New Kingman Butler|
|New River||Nogales||Oro Valley|
|Queen Creek||Rio Rico||Saddlebrooke|
|Sahuarita||San Luis||San Tan Valley|
|Sierra Vista||Sierra Vista Southeast||Somerton|
|Sun City||Sun City West||Sun Lakes|
|Valencia West||Verde Village||Yuma|
|Texarkana||Texas City||The Colony|
|The Woodlands||Timberwood Park||Tomball|
|Trophy Club||Tyler||Universal City|
|West Odessa||West University Place||White Settlement|
|Boulder City||Carson City||Elko|
|Sparks||Spring Creek||Spring Valley|
|Summerlin South||Sunrise Manor||Sun Valley|
|Hidalgo||Highland Village||Horizon City|
|Lake Jackson||Lakeway||La Marque|
|League City||Leander||Leon Valley|
|Mission||Mission Bend||Missouri City|
|Nederland||New Braunfels||New Territory|
|North Richland Hills||Odessa||Orange|
|Port Arthur||Portland||Port Lavaca|
|Richmond||Rio Grande City||Robinson|
|Saginaw||San Angelo||San Antonio|
|San Benito||San Juan||San Marcos|
|Sugar Land||Sulphur Springs||Sweetwater|