Bitumen Emulsion SS-1 and CRS-1 Comparison
Last updated: 2026-10-01
Bitumen Emulsion SS-1 and CRS-1 Comparison
SS-1 is a slow-setting anionic bitumen emulsion, while CRS-1 is a rapid-setting cationic emulsion. SS-1 typically contains 57–65% residual bitumen and is used for tack coats, slurry seals, and cold mixes, whereas CRS-1 contains 60–65% residual bitumen, carries a positive charge, and is engineered primarily for chip seal and surface dressing applications where fast breaking (under 5 minutes) is required. In bulk export volumes (20–24 MT flexitanks), SS-1 usually prices around $380–$450 per MT FOB, while CRS-1 ranges $400–$480 per MT FOB, depending on base bitumen grade, emulsifier package, and destination port.
What Are SS-1 and CRS-1 Bitumen Emulsions?
Both products are oil-in-water dispersions in which penetration-grade bitumen (typically 50/70 or 60/70 pen) is sheared into microscopic droplets and stabilized with an emulsifier. The key difference is the emulsifier charge and setting speed, which governs how the emulsion interacts with aggregate surfaces and how quickly it reverts to bitumen after application.
| Property | SS-1 | CRS-1 |
|---|---|---|
| Setting class | Slow-set | Rapid-set |
| Charge type | Anionic (negative) | Cationic (positive) |
| Standard | ASTM D977 / AASHTO M140 | ASTM D2397 / AASHTO M208 |
| Residue by distillation | 57% min | 60% min |
| Saybolt Furol viscosity @25°C | 20–100 s | 20–100 s |
| Storage stability, 24h | ≤1% | ≤1% |
| Breaking time | 30–120 min | 1–5 min |
| Typical price (FOB, MT) | $380–$450 | $400–$480 |
SS-1 ("Slow-Setting 1") is designed to remain workable long enough for mixing with aggregate. Its anionic (negative) charge bonds well with negatively charged siliceous aggregates such as quartz, granite, and sandstone, and holds a strong affinity for limestone as well.
CRS-1 ("Cationic Rapid-Setting 1") breaks almost immediately on contact with aggregate, producing a fast initial set. Its positive charge makes it bond strongly to negatively charged aggregates — the majority of common road stones — even in damp conditions, which is why it dominates chip seal programs in Europe, the Middle East, and Latin America.
Performance Comparison: Breaking Time, Adhesion, and Curing
The most operationally significant difference is breaking speed, which dictates the type of paving equipment and crew timing required.
| Parameter | SS-1 | CRS-1 |
|---|---|---|
| Breaking time | 30–120 minutes | 1–5 minutes |
| Mixing with aggregate | Yes (cold mix) | No (breaks too fast) |
| Recommended for chip seal | No | Yes |
| Recommended for slurry seal | Yes | Limited |
| Tack coat application rate | 0.15–0.25 kg/m² | 0.15–0.30 kg/m² |
| Chip seal spray rate | Not applicable | 0.8–1.6 kg/m² |
| Cure to traffic | 2–4 hours (warm, dry) | 30–60 minutes |
| Adhesion (wet aggregate) | Moderate | Excellent |
- SS-1 gives crews a wide window to place, level, and compact slurry or cold mix before it sets. This is critical on large slurry seal jobs where a single lane can be 2–5 km long.
- CRS-1 sets so fast that a chip spreader must follow the sprayer within 30–90 seconds to achieve proper aggregate embedment. The payoff is that the road can reopen to traffic in under an hour on a dry, warm day (>25°C).
- Adhesion on wet/damp aggregate is where CRS-1 wins decisively. The cationic droplet charge displaces water from the stone surface, while anionic SS-1 can be stripped by moisture unless a dope additive (0.3–0.5% by weight) is used.
Typical Applications and Where Each Wins
Choosing between SS-1 and CRS-1 is almost always dictated by application type, not price.
| Application | Best Choice | Reason |
|---|---|---|
| Tack coat | Both | SS-1 on siliceous; CRS-1 faster cure |
| Slurry seal (microsurfacing) | SS-1 (or CSS-1) | Needs long mixing time |
| Chip seal / surface dressing | CRS-1 | Fast break + wet adhesion |
| Cold mix patching | SS-1 | Workability with aggregate |
| Prime coat on granular base | SS-1 | Slow penetration |
| Fog seal | Both | Low dilution rate (1:1 to 1:3) |
| Cape seal (slurry over chip) | CRS-1 + SS-1/CSS-1 | Two-product sequence |
- SS-1 exports are commonly shipped to markets doing slurry seal and cold recycling, particularly in Asia and Africa where mixing-grade emulsions are in demand.
- CRS-1 exports dominate chip seal and surface dressing tenders across the Gulf, North Africa, and Latin America, where fast reopening to traffic and resistance to moisture are the top priorities.
- A two-product package (CRS-1 for the chip seal, SS-1/CSS-1 for the slurry) is common on full road rehabilitation projects and can justify a single shipment of 40–48 MT across two flexitanks.
Pricing, Packing, and Lead Times (2024–2025)
Emulsion pricing tracks base bitumen (pen 60/70) plus the emulsifier package (typically $40–$80 per MT) and logistics. Below are indicative bulk-export figures.
| Cost Element | SS-1 | CRS-1 |
|---|---|---|
| Base bitumen (60/70 pen) | $340–$400/MT | $340–$400/MT |
| Emulsifier + additives | $40–$70/MT | $45–$80/MT |
| Processing & QC | $15–$25/MT | $15–$25/MT |
| FOB price (bulk) | $380–$450/MT | $400–$480/MT |
| Price per flexitank (24 MT) | $9,120–$10,800 | $9,600–$11,520 |
| Price per ISO tank (20 MT) | $7,600–$9,000 | $8,000–$9,600 |
Packing options:
- Flexitank in 20' container: 24 MT — most economical for large tenders, but limited discharge ports.
- ISO tank: 20 MT — preferred where port discharge pumps are available.
- Steel drums: 180–200 kg net — used for small jobs and remote sites; adds $60–$90/MT.
- IBC totes: 1,000 kg — niche, adds $80–$120/MT.
Lead times (typical, from order to load port):
- SS-1: 10–18 days (production + QC + stuffing)
- CRS-1: 12–20 days (extra emulsifier lead time)
- Ocean transit: 7 days (intra-regional) to 35 days (Far East → West Africa)
Storage and shelf life: both products store 6 months at 5–40°C; avoid freezing and direct sun. SS-1 and CRS-1 must never be mixed or stored in the same tank — the opposite charges cause instant coagulation.
How to Choose: Decision Framework
Use the following logic to select the right grade:
- Application = chip seal / surface dressing? → CRS-1.
- Application = slurry seal, microsurfacing, cold mix? → SS-1 (or CSS-1 for cationic mixing).
- Aggregate is wet or job is in a humid climate? → CRS-1 (cationic adhesion).
- Aggregate is siliceous and job is dry? → SS-1 anionic works and often costs less.
- Need fast reopening to traffic (<1 hour)? → CRS-1.
- Need extended workability (>30 min)? → SS-1.
- Tender specifies ASTM D977? → SS-1. ASTM D2397? → CRS-1.
- Port has no heated storage? → either grade is fine at ambient; just avoid freezing.
Cost-per-m² reality check: For a standard chip seal at 1.2 kg/m² CRS-1, material cost is roughly $0.48–$0.58/m². For a tack coat at 0.2 kg/m² SS-1, material cost is $0.08–$0.09/m². Always model landed cost — ocean freight, demurrage, and inland trucking can add $40–$120/MT and frequently exceed the FOB price gap between the two grades.
FAQ: Bitumen Emulsion SS-1 vs CRS-1
Q1: What is the main difference between SS-1 and CRS-1?
SS-1 is a slow-setting anionic emulsion, while CRS-1 is a rapid-setting cationic emulsion. The charge difference controls adhesion to aggregate, and the setting class controls how fast the emulsion breaks — CRS-1 in 1–5 minutes versus 30–120 minutes for SS-1.
Q2: Can CRS-1 be used for slurry seal?
No. CRS-1 breaks too quickly (1–5 minutes) to mix with slurry aggregate. For slurry seal, use SS-1 or a cationic slow-set grade like CSS-1. Using CRS-1 in slurry equipment typically causes plugging and premature set in the mixing chamber.
Q3: Is CRS-1 more expensive than SS-1?
Yes, usually by $20–$30 per MT FOB. CRS-1 requires a more expensive cationic emulsifier package, and indicative bulk pricing runs $400–$480/MT versus $380–$450/MT for SS-1. The gap can widen in tight emulsifier markets.
Q4: What is the residual bitumen content of SS-1 and CRS-1?
SS-1 typically has 57% minimum residue by distillation, and CRS-1 has 60% minimum per ASTM D2397/AASHTO M208. Higher residue means less water to evaporate and faster cure, which is one reason CRS-1 is preferred for chip seal.
Q5: Can SS-1 and CRS-1 be stored in the same tank?
No. Mixing anionic SS-1 with cationic CRS-1 causes immediate coagulation and destroys both products. They must be stored in separate, dedicated tanks, pumps, and lines, and equipment should be flushed between uses.
Closing CTA: Model Your Landed Cost with the 6Tar Cost Calculator
Before you commit to a 24 MT flexitank or a multi-container tender, run the numbers. The 6Tar cost calculator lets you input FOB price, ocean freight, port charges, inland trucking, and duty to get a true landed cost per MT and per m² for both SS-1 and CRS-1. Compare grades, packing options (flexitank vs. ISO tank vs. drums), and destination ports side by side — then lock in your order with confidence. Start your calculation at 6Tar today.