About STP ShaliBit 81

ShaliBit 81 is a special grade modified bitumen manufactured by STP Limited, one of India’s oldest names in construction chemicals and bituminous products. It sits in STP’s ShaliBit road-surfacing family as a hot-applied black binder rather than a cold-applied coating. On site it is melted, blended with mineral aggregate or other job components, and laid to form the binding matrix that holds a flexible pavement together. The grade is formulated to stay workable through the mixing and laying window yet set into a tough, water-resistant film that survives monsoon exposure and the daily heat-cool cycle typical of Indian roads and yards.

For engineers and contractors, the appeal of ShaliBit 81 is predictability. STP supplies it to a consistent characteristic profile with good resistance to oxidative degradation, so batches behave the same way across a project. It has genuine ductility, letting the pavement flex under traffic and thermal movement without the brittle cracking that shortens surface life. Because it also resists rain penetration and adheres firmly to concrete and other substrates, the same material crosses over into runway construction and a range of industrial bituminous duties where a dependable, heat-melt binder is needed. Space Arc Engineering supplies it as an authorised STP project distributor across Delhi NCR and Pan-India.

The technical insight

ShaliBit 81 works because bitumen is a thermoplastic binder: it flows when hot and stiffens when cool, which is exactly what a pavement or coating operation needs. Heated to 120-150 degrees C it becomes fluid enough to fully coat aggregate and wet the substrate, then on cooling it locks the mix into a cohesive, load-spreading mass. The grade is tuned so its consistency and ductility (greater than 60 cm at 25 degrees C) let the laid film stretch rather than snap when the surface expands and contracts through the day. Its good resistance to oxidative degradation matters over the long term: ordinary bitumen hardens and embrittles as air and UV oxidise it, but a formulation that slows this ageing keeps the pavement flexible and watertight for longer. The high flash point (greater than 190 degrees C) gives a comfortable safety margin above the working temperature, and the low water permeability of the cured film is what lets the same binder double as a protective, moisture-excluding layer in industrial work.

Where it is used

• Binder for flexible pavement construction and periodic road resurfacing
• Maintenance and patch repair of existing bituminous roads
• Airport runway, taxiway and apron construction
• Hot-mix bituminous works for yards, hardstands and access roads
• Industrial bituminous duties needing a water-excluding heat-melt binder
• Protective bituminous coating over concrete and metal substrates
• Sealing and surfacing where rain and temperature cycling resistance is required

Key advantages

• Withstands thermal expansion and contraction without cracking
• Ductility greater than 60 cm at 25 degrees C for a flexible, fatigue-tolerant film
• Good adhesion to concrete and other prepared surfaces
• Prevents penetration of water and resists rain exposure
• Good resistance to oxidative degradation for longer service life
• High flash point greater than 190 degrees C gives a safe working margin
• Supplied to a consistent STP characteristic profile for batch-to-batch reliability
• Backed by authorised STP distribution and site support from Space Arc

Limitations & considerations

• Hot-applied only: needs heating to 120-150 degrees C and trained handling of molten bitumen
• Not a ready-to-use cold coating, primer or waterproofing membrane out of the drum
• Softening point above 40 degrees C means performance depends on correct grade selection for the climate and duty
• Requires a clean, sound, dry and mechanically prepared substrate for proper adhesion
• Best used within 12 months of supply while sealed; ageing bitumen stiffens over time
• Not a structural repair mortar or crack-injection product; it is a surfacing and coating binder

Selection & best practice

Specifications

Industry use cases

How we position STP ShaliBit 81

ShaliBit 81 is STP’s road-surfacing and industrial bitumen binder, chosen where a hot-applied, water-excluding paving binder is needed rather than a cold coating or membrane. Within the same STP family, its sibling ShaliBit 67 offers a different characteristic profile (softening point above 40 degrees C, penetration above 80 dmm) for teams matching the grade to climate and duty. Where the job is priming a substrate before bituminous work, STP ShaliTex bituminous primer is the natural companion, and for finished roof or terrace waterproofing STP’s bituminous membranes such as the SuperThermoLay APP range are the purpose-built systems. For cementitious deck or wet-area waterproofing that sits outside the bituminous route, Space Arc also supplies Fosroc, Dr. Fixit and MC-Bauchemie systems and can steer specifiers to the correct product for the substrate and exposure.

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