Construction Methodology for Applying of Tack Coat

Methodology for Applying Tack Coat

1.1         TACK COAT:

Application of Tack coat shall be in accordance with clause 503 of MORTH specifications.

1.2         MATERIAL:

The binder used for tack coat shall be bitumen emulsion RS-1 (Rapid setting grade-1) complying with IS 8887.

1.3         EQUIPMENT:

1.    Truck mounted bitumen pressure sprayer.

2.    Compressor –150 Cfm

3.    Mechanical broom (To be used wherever required)

1.4         PREPARATION OF BASE:

The surface on which tack coat is to be applied shall be cleaned by manual labours and all loose particles, dust etc. shall be removed & caked mud, dung etc. shall be scrapped. The surface will be swept by mechanical broom if required. High pressure air jet from a compressor shall be used to remove dust or loose material.

1.5         APPLICATION OF TACK COAT:

Truck mounted bitumen pressure sprayer shall be used for uniform application of emulsion RS-1, at the rate specified in the contract. The temperature of emulsion at the time of spraying shall be in the range of 20 C to 70 C. Tack coat shall be left to cure for a period of 2-3 hours or till the surface becomes tacky. No vehicles shall be allowed on the tack coat. Rate of application as per clause no. 503.4.3 and table no. 500-5 of the MORTH 5^th revision.

1.6         QUALITY CONTROL:

The control tests on material and work shall be in accordance with MORTH specifications para 503.5.

1)    Quality of binder- As per IS: 8887.

2)    Rate of spray of binder – Three tests per day.

1.7         SITE RECORDS:

Following records are required to maintain by site engineer/ field laboratory: -

1)         Request for inspection (RFI)

2)         Check list

3)         Rate of spray

4)         Location and length of work (Chainage)

5)         Weather record

6)         Reasons for delay or obstructions, if any

1.8         Manpower Assignment to control the work:

For proper controlling of work following personnel are responsible for construction of kerb and finishing operation as well as quality control.

1)         Material Engineer   -Responsible for controlling of rate of spray of emulsion.

2)         Highway Engineer -Shall be overall responsible for progress / quality of work.

3)         Site engineer  -Shall be responsible for proper cleaning and progress of work.

4)         Surveyor – Shall be responsible for proper line and level.

5)         Mechanical Manager -Responsible to manage the timely and breakdown free movement of equipment.

Arrangement of Traffic

(i)            During the period of construction, arrangements for traffic shall be made in accordance with the provision of clause 112 and safety arrangement as required.