What is the thickness of tack coat?

From Table 1, based on the 0.75 foot design for hot mix asphalt, the estimated number of layers for total thickness between 0.51 and 0.75 foot or less is three layers. Because the hot mix asphalt is placed on aggregate base the number of layers requiring tack coat is reduced from three to two.

What material is used for tack coat?

The most common tack coat materials are asphalt emulsions, with slow setting emulsions (SS-1, SS-1h, CSS-1, and CSS-1h) being the most common (1). Other asphalt emulsions which are increasingly used for tack coat including rapid- setting emulsions such as RS-1, RS-2, CRS-1 and CRS-2.

What is the thickness of prime coat?

For a normally clean environment, a coat of up to 50 microns is considered adequate. For a dusty or humid location requiring constant servicing and cleaning, a thicker coat, say, up to 70–80 microns, is considered to be adequate. A thickness of up to 50 microns is possible through one coat of primer and paint.

Is there a difference between prime coat and tack coat?

Prime functions as a protector from rain for both types of bases. A prime coat should not be confused with a tack coat. Tack is an adhesive for gluing two asphalt layers together. A subgrade or rock base is not a single component.

What is the application rate for tack coat?

The application rate will vary from 0.05 to 0.15 gal/yd², depending on the condition of the old pavement surface. The pavement course surface should be evaluated to determine the amount of tack to be applied.

Applying Tack Coat - Best Practices

How do you measure a tack coat?

Therefore, the estimated quantity of tack coat is determined as follows: Quantity of Tack Coat = (quantity of emulsion in gallons) ÷ (gallons of emulsion per ton) = 61,952 gallons ÷ 240 gal./ton = 258.1 tons Quantity of Tack Coat = 259 tons.

What is bituminous tack coat?

Bitumen, or tack coat, is a by-product of petroleum refinement that is used as a binding agent in asphalt-based products. A tack coat is essentially a type of industrial glue that is used in the pavement construction trade to bind together layers of asphalt on roadways.

What is the minimum thickness of seal coat?

Explanation: The minimum thickness of the seal coat required is 20mm for bitumen pavement, seal coat is a layer above the flexible pavement surface. Explanation: The aggregate impact value should not be more than 30% for aggregate used in bitumen if it is less than 30 the aggregate may be replaced.

Is tack coat waterproof?

General Information. TACK COAT NO. 2 is part of a wide range of specialist waterproofing, surfacing and repair materials manufactured and supplied by GCP.

What is RS1 bitumen?

RS1 Bitumen Emulsion is specially designed water based bitumen emulsion with low viscosity and fast setting time that makes it an ideal product for spray application. It is chocolate brown in colour and is a free flowing liquid at ambient temperature.

What is tack coat in road?

A tack coat is an adhesive material applied between layers of the asphalt concrete that is laid down for road construction. The adhesive when applied correctly, helps to prevent the degradation of the road by keeping the asphalt concrete layers together. Fig. 1 shows the application of a tack coat over a pavement.

What is seal coat and tack coat?

Tack coat is generally of higher viscosity at the rate of kg/10m2 depends on type of surface. Seal Coat. Seal coat is mainly applied on impervious surface of bituminous pavements as a top coat. A pre mixed sand bitumen (hot mix) seal coat is commonly used over the premixed carpet.

What is a tack coat in painting?

A tack coat is a light mist that you allow to set for five minutes. The texture of the tack coat will help hold the paint in place and reduce runs.

How long does it take for tack coat to dry?

Usually, most tack coat materials require 1 to 2 hr to fully cure (set). It is generally recommended to let the materials completely cure before placing a new HMA layer on top of them. Various studies confirmed this recommendation by showing that longer curing time results in better interface strength performance.

What is the density of asphalt?

Standard density for asphalt is 145 lb/ft³ (2322 kg/m³). Multiply the volume by the density (in the same units) to get the weight.

What is the difference between bond coat and tack coat?

Bond coats work as the glue between the layers of asphalt that make up a roadway or pavement. A correctly used tack coat will waterproof the surface and prevent the ingress of water. This serves to protect the surface from the development of potholes and other defects brought about from water penetration.

What is SS1 in road construction?

Bitumen Emulsion SS1 / SS1h are slow-setting, anionic type of asphalt emulsions manufactured according to specifications of ASTM D977 – “Standard Specifications for Anionic Emulsified Asphalt.” It is a dispersion of small droplets of penetration grade asphalt cement in water with the aid of an emulsifier.

Is prime coat necessary?

At one time it was thought that a prime coat was an essential element of good asphalt pavement construction. However, asphalt prime materials and the gradation of aggregate bases have changed over the years and applications of prime are no longer necessary for most asphalt pavements.

What is the maximum limit of subgrade thickness?

What is the maximum limit of sub grade thickness? Explanation: The prepared sub grade is limited to a maximum of 300 mm, in any case it must not exceed 300 mm. Participate in Highway Engineering Certification Contest of the Month Now!

What is the minimum thickness of road?

As per IRC: 37-2001, sub-base the thickness should not be less than 150 mm for design traffic less than 10 msa (million standard axles) and 200 mm for design traffic of 10 msa and above.

What is the thickness of pavement?

The selection of the pavement and gravel thickness is based on three criteria (Figure 3): (1) the thickness of the asphalt pavement is 0.1 m and the gravel base thickness is 0.2 m, which is shortened to 10 to 20 types; (2) the thickness of the asphalt pavement is 0.18 m and the gravel base thickness is 0.2 m, which is ...

What is liquid tack?

A tack coat is a thin bituminous liquid asphalt, emulsion or cutback layer applied between HMA pavement lifts to promote bonding.

What is TAG coat?

Tack coat is a thin layer of asphalt that ensures the bonding between old and new asphalt layers. It is also used in construction or for renovation of roads to achieve better strength. Tack coat is sticky, which is very important for forming a secure bond between the two layers of asphalt.

How many layers are in a road?

Road construction vocabulary

Roads are made up of four layers.

How do you calculate bitumen?