Tentative Specification for Single Coat Bituminous Surface Dressing (First Reprint)

The scope of IRC 17 covers the construction of single coat bituminous surface dressing on prepared road bases or pavements. It specifies the use of bituminous materials conforming to IS standards (e.g., IS 73-1961, 215-1961) and cover materials such as crushed stone or gravel with defined physical properties (abrasion value ≤ 35%, impact value ≤ 30%, flakiness index ≤ 25%, stripping value ≤ 25%, water absorption ≤ 1%, soundness loss ≤ 12%, bulk density ≥ 1120 kg/m³ for slag) as per Table 1. Aggregate gradation requirements for first and subsequent coats are given in Table 2, e.g., 100% passing 22.4 mm sieve and retained on 11.2 mm sieve for first coat. Application rates of bituminous binders and aggregates per 10 m² are provided in Table 3, e.g., 17.1 to 19.5 kg straight run bitumen for 0.14 to 0.15 m³ of 13.2 mm aggregate. Construction methods include surface preparation, binder application, cover material spreading, rolling, and traffic opening guidelines. These ensure uniform, durable surface dressing as per IRC 17 specifications.

Sources: Clause 2.2.2, Table 1, Clause 2.2.3, Table 2, Clause 3.4, Table 3, Clause 3.3, Clause 3.5, Clause 3.6, Clause 3.8

Key materials specifications from IRC 17 for bituminous surface dressing include:

• Bituminous Materials: Must conform to ISI standards (IS 73-1961, 215-1961, 217-1961, 454-1961) with binder grades selected based on climate (Clause 2.1).

• Cover Materials: Crushed stone, slag, or gravel with clean, durable, cubical fragments free from deleterious matter. Preferably hydrophobic and low porosity (Clause 2.2.1).

• Physical Requirements of Aggregates (Table 1):

  Property	Max/Min Value	Test Method
  Abrasion value (Los Angeles)	Max 35%	IS 2386 (Part IV)
  Aggregate impact value	Max 30%	IS 2386 (Part IV)
  Flakiness index	Max 25%	IS 2386 (Part I)
  Stripping value	Max 25%	IS 6241
  Water absorption (except slag)	Max 1%	IS 2386 (Part III)
  Soundness (slag only)	Max 12% loss (5 cycles sodium sulphate)	IS 2386 (Part V)
  Unit weight (slag only)	Min 1120 kg/m³	IS 2386 (Part III)

• Aggregate Size (Clause 2.2.3 and Table 2):

  • First coat: 100% passing 22.4 mm sieve and retained on 11.2 mm sieve.
  • Subsequent coats: 100% passing 13.2 mm sieve and retained on 6.7 mm sieve.

• Application Rates (Table 3): Approximate quantities of bituminous binder and aggregates per 10 m² vary by aggregate size and binder type (straight run bitumen, road tar, cutback, emulsion).

These specifications ensure quality and durability of bituminous surface dressing as per IRC 17.

Sources: Clause 2.1, Clause 2.2.1, Table 1, Clause 2.2.3, Table 2, Clause 3.4, Table 3

Key specifications for bituminous materials in single coat bituminous surface dressing per IRC 17 include:

• Bituminous Materials: Must conform to ISI standards (IS 73-1961, 215-1961, 217-1961, 454-1961) with binder grades selected based on climate (Clause 2.1).

• Cover Materials: Crushed stone, slag, or gravel with clean, durable, cubical fragments, low porosity, and hydrophobic nature preferred (Clause 2.2.1).

• **Physical Requirements of Aggregates (Table 1):

• Aggregate Size (Table 2):

• Application Rates (Table 3): Approximate bitumen and aggregate quantities per 10 m² vary by aggregate size and binder type (straight run bitumen, road tar, cutback, emulsion). For example, for 13.2 mm aggregate on water-bound macadam surfaces, straight run bitumen is applied at 17.1 to 19.5 kg per 10 m².

• Construction Notes: Surface must be dry, clean, and prepared; bituminous material sprayed uniformly at proper temperature; cover material spread immediately and rolled; traffic opening depends on binder type and curing (Clauses 3.1 to 3.8).

These details are from IRC 17 clauses 2.1, 2.2, 3, and Tables 1, 2, and 3.

Sources: Clause 2.1, Clause 2.2.1, Clause 2.2.2, Clause 2.2.3, Clause 3.1, Clause 3.4, Clause 3.5, Clause 3.6, Clause 3.8, Table 1, Table 2, Table 3

Key specifications for Cover Materials per IRC 17 include:

• Material Type: Crushed stone, slag, gravel (shingle), or other stones with clean, strong, durable, cubical fragments free from disintegrated pieces, salts, alkali, vegetable matter, dust, and coatings (Clause 2.2.1).

• **Physical Requirements (Table 1):

• Size Grading (Table 2):

• Cover Material Application: Immediately after bituminous binder application, cover material is spread uniformly and rolled to achieve a uniform surface with max 6 mm variation over 3 m length (Clauses 3.5, 3.6).

These requirements ensure durability and proper bonding in bituminous surface dressing as per IRC 17 Clause 2.2 and 3.

Sources: Clause 2.2.1, Table 1, Table 2, Clauses 3.5, 3.6

Key construction methods per IRC 17 include:

• Preparation of Road Surface (Clause 3.3): The base must be shaped, compacted, dry, and clean of dust and foreign matter before applying bituminous binder. Defective areas must be cut out and patched.

• Application of Bituminous Material (Clause 3.4): Bitumen is sprayed uniformly at suitable temperature using mechanical sprayers. Excess bitumen must be removed immediately.

• Application of Cover Material (Clause 3.5): Immediately after bitumen application, cover aggregates are spread uniformly by hand or mechanical gritters and broomed for uniformity.

• Rolling (Clause 3.6): The finished surface must be uniform with max 6 mm variation over 3 m length.

• Opening to Traffic (Clause 3.8): For straight run bitumen or tar, open next day; for cutback or emulsion, open after curing.

• Table 3: Approximate rates of bituminous materials and aggregates per 10 m²:

These methods ensure proper bonding, durability, and surface quality of bituminous surface dressing.

Sources: Clause 3.3, Clause 3.4, Clause 3.5, Clause 3.6, Clause 3.8, Table 3

As per IRC 17 Clause 3.1, weather and seasonal limitations require all construction equipment to be on-site and in good condition to ensure proper work. The road surface must be dry and thoroughly cleaned before applying bituminous binders (Clause 3.3). Bituminous materials should be sprayed uniformly at appropriate temperatures (Clause 3.4). Immediately after binder application, cover materials must be spread uniformly as per quantities in Table 3 (Clause 3.5). Rolling should produce a uniform surface with no variation greater than 6 mm over 3 m (Clause 3.6). Opening to traffic depends on binder type: for straight run bitumen or road tar, traffic can open the next day or immediately with speed restrictions; for cutback bitumen and emulsion, curing is required before opening (Clause 3.8). Table 3 provides approximate application rates of binders and aggregates per 10 m², critical for seasonal application control.

Sources: Clause 3.1, Clause 3.3, Clause 3.4, Clause 3.5, Clause 3.6, Clause 3.8, Table 3

Preparation of road surface as per IRC 17 involves several key steps and specifications:

• The underlying course must be prepared, shaped, and conditioned to a uniform grade and section, with any depressions or potholes properly made up and compacted well in advance (Clause 3.3).
• Defective parts should be cut out and patched with new material, not just overlaid.
• The surface must be dry and thoroughly cleaned before applying binder, using hard brushes, softer brushes, and blowing off fine dust with sacks or gunny bags.
• For stabilised soil or porous aggregates, a bituminous primer should be applied uniformly (Clause 3.3).
• Old bituminous surfaces must be mechanically swept and cleaned free of loose matter and dry before treatment.
• Bituminous material is sprayed uniformly at appropriate temperature using mechanical sprayers (Clause 3.4).
• Cover material is spread immediately after binder application, preferably by mechanical gritters, and broomed for uniformity (Clause 3.5).
• Finished surface must be uniform with no variation greater than 6 mm over 3 m length (Clause 3.6).
• Opening to traffic depends on binder type; straight run bitumen surfaces can open next day, cutback bitumen and emulsion surfaces require curing (Clause 3.8).

Key Table 3 (Approximate rates per 10 m²):

Aggregate gradation for first coat and renewal coats:

• First coat: 100% passing 22.4 mm sieve and retained on 11.2 mm sieve.
• Renewal coats: 100% passing 13.2 mm sieve and retained on 6.7 mm sieve (Clause 22.4).

This ensures proper surface preparation and application for durable bituminous surface dressing.

Sources: Clause 3.3, Clause 3.4, Clause 3.5, Clause 3.6, Clause 3.8, Clause 22.4, Table 3

The application of bituminous material as per IRC 17 involves several key steps and specifications:

• Surface Preparation: The base must be dry, clean, and free from dust or loose material. Prime coats should be fully cured before applying bitumen (Clause 3.3).

• Bituminous Material Application: Bitumen is sprayed uniformly at a temperature suitable for the binder and equipment, preferably using mechanical sprayers (Clause 3.4).

• Cover Material: Immediately after bitumen application, cover aggregates are spread uniformly by hand or mechanical gritters, followed by brooming for uniformity (Clause 3.5).

• Rolling: The surface is rolled to achieve uniformity with no variation greater than 6 mm over 3 m length (Clause 3.6).

• Opening to Traffic: For straight run bitumen or road tar, traffic can be allowed the next day; for cutback bitumen or emulsion, curing is required before opening (Clause 3.8).

• Aggregate Size and Quantities: Table 3 provides approximate application rates per 10 m²:

• Aggregate Quality: Aggregates must be clean, durable, cubical, and meet physical requirements such as max 35% abrasion value, max 25% flakiness index, max 1% water absorption, etc. (Table 1).

• Gradation: For first coat, 100% passing 22.4 mm sieve and retained on 11.2 mm sieve; for subsequent coats, 100% passing 13.2 mm sieve and retained on 6.7 mm sieve (Table 2).

These specifications ensure proper bonding, durability, and surface quality of bituminous surface dressing as per IRC 17 clauses 3.3 to 3.8 and Tables 1, 2, and 3.

Sources: Clause 3.3, Clause 3.4, Clause 3.5, Clause 3.6, Clause 3.8, Table 1, Table 2, Table 3

The application of cover material in single coat bituminous surface dressing per IRC 17 involves the following key points:

• Cover Material Size: For the first coat on water-bound macadam, aggregates must be 100% passing through a 22.4 mm square mesh sieve and retained on an 11.2 mm square mesh sieve. For subsequent or renewal coats, aggregates must be 100% passing through a 13.2 mm square mesh sieve and retained on a 6.7 mm square mesh sieve (Clause 22.4).

• Cover Material Quality: Aggregates should be clean, strong, durable, cubical, free from dust, vegetable matter, and other deleterious substances. Physical requirements include max 35% abrasion value, max 30% impact value, max 25% flakiness index, max 25% stripping value, max 1% water absorption (except slag), and min 1120 kg/m³ bulk density for slag (Table 1).

• Application Process: Immediately after spraying bituminous binder uniformly, cover material is spread uniformly by hand or mechanical gritter and broomed to ensure uniformity (Clause 3.5).

• Approximate Quantities: Table 3 specifies quantities of aggregates and binders per 10 m², e.g., for 13.2 mm aggregate in first coat, 0.14 to 0.15 m³ aggregate and 17.1 to 19.5 kg straight run bitumen.

• Surface Finish: After rolling, surface variation shall not exceed 6 mm over 3 m length (Clause 3.6).

These specifications ensure proper bonding and durability of the surface dressing.

Table 2: Aggregate Size Requirements

Table 3: Approximate Rate of Application of Bituminous Materials and Aggregates

Sources: Clause 22.4, Table 1, Table 2, Table 3, Clause 3.5, Clause 3.6

Key specifications for Rolling Cover Materials per IRC 17 include:

• Cover Material Size: For first coat on water-bound macadam, aggregates must be 100% passing through 22.4 mm square mesh sieve and retained on 11.2 mm square mesh sieve; for subsequent coats, 100% passing through 13.2 mm square mesh sieve and retained on 6.7 mm square mesh sieve (Clause 22.4).

• Aggregate Quality: Aggregates should be clean, strong, durable, cubical, hydrophobic, and low porosity, meeting physical requirements such as max 35% abrasion value, max 30% impact value, max 25% flakiness index, max 25% stripping value, max 1% water absorption (except slag), and min 1120 kg/m³ bulk density for slag (Table 1).

• Application Rates: Table 3 specifies approximate quantities of bituminous binder and aggregates per 10 m², e.g., for 13.2 mm aggregate size, 0.14 to 0.15 m³ aggregate with 17.1 to 22 kg straight run bitumen.

• Surface Preparation and Rolling: The surface must be dry, clean, and uniformly prepared before binder application. Cover material is spread immediately after binder application and rolled to achieve a uniform surface with max 6 mm variation over 3 m length (Clauses 3.3, 3.4, 3.5, 3.6).

These ensure durable, uniform bituminous surface dressing as per IRC 17.

Sources: Clause 22.4, Table 1, Table 2, Table 3, Clauses 3.3, 3.4, 3.5, 3.6

As per IRC 17 Clause 3.8, the opening to traffic depends on the type of bituminous binder used:

• For straight run bitumen or road tar, the finished surface shall be opened to traffic the next day. If immediate opening is necessary, traffic speed must be limited to 16 km/h until the following day.
• For cutback bitumen and emulsion, the surface must be kept closed until sufficiently cured to hold cover aggregates.

Traffic control measures such as barricading and watchmen are required.

Additionally, Table 3 provides approximate application rates of bituminous materials and aggregates per 10 m²:

This ensures proper binder and aggregate application for surface dressing before opening to traffic.

Sources: Clause 3.8, Table 3

Key specifications for Application Rates and Aggregate Gradation per IRC 17 are as follows:

Aggregate Gradation:

• For surfacing water-bound macadam first coat: 100% passing through 22.4 mm square mesh sieve and retained on 11.2 mm square mesh sieve.
• For subsequent or renewal coats: 100% passing through 13.2 mm square mesh sieve and retained on 6.7 mm square mesh sieve (Clause 22.4).

Application Rates (per 10 m²):

(Clause 3.4 and Table 3)

Additional Notes:

• Aggregates must be clean, strong, durable, cubical, and free from deleterious materials (Clause 2.2.1).
• Physical requirements include max 35% abrasion value, max 25% flakiness index, max 1% water absorption, etc. (Table 1).
• Proper surface preparation and uniform application of binder and cover material are essential (Clauses 3.3 to 3.6).

This ensures proper bonding and durability of bituminous surface dressing.

Sources: Clause 22.4, Clause 3.4, Table 3, Clause 2.2.1, Table 1