Content Overview
Bitumen A70: A 2025 Handbook for Engineers, Buyers & Visionary Builders
From granular chemistry to global market forces, this deep-dive unpacks everything you need to specify, source, and future-proof projects with Bitumen A70.
1 | What Exactly Is Bitumen A70?
Bitumen A70—also marketed as A-70, AH-70, A70#, “China grade 70”, or simply penetration-grade 70/60–70—is a petroleum asphalt binder whose penetration index centers on ≈70 × 10⁻¹ mm under the standard 25 °C, 100 g, 5 s test. In the Chinese GB/T 15180 and GB/T 22086 frameworks it slots between A90 (softer) and A50 (harder), while in Russian GOST 33133 it corresponds closely to BND 70/100 and in ASTM terminology to 60/70 paving-grade bitumen. russiangost.com
This nominally “medium-hard” rheology makes A70 a workhorse for dense-graded hot-mix asphalt (HMA) in temperate and warm climates where flexibility at low temperature is needed without sacrificing rut resistance.
2 | Why A70 Matters in 2025
Infrastructure Boom: Global road-building budgets exceeded USD 39 billion in 2024 for modified bitumen alone, with a CAGR of 6.7 % forecast to 2030. Grand View Research
Decarbonisation Pressure: Contractors now juggle performance with CO₂ targets—A70’s ready compatibility with warm-mix additives and high-RAP (reclaimed asphalt pavement) designs accelerates compliance.
Supply Chain Shifts: Sanctions on certain crude slates have tightened vacuum resid bases; Chinese and Middle-East refiners stepped up A70 output, driving new spot-buy habits and packaging formats (Jumbo bags, containerised bitu-bags).
3 | Physicochemical Profile
| Property | Test Method* | A70 Typical | ASTM 60/70 | A50 | A90 |
|---|---|---|---|---|---|
| Penetration @ 25 °C (0.1 mm) | D5 / GB T4505 | 65-75 | 60-70 | 45-55 | 80-90 |
| Softening Point (°C) | D36 / GB T4506 | 49-56 | 49-56 | 52-60 | 46-52 |
| Viscosity @ 135 °C (Pa·s) | D4402 | 0.34-0.42 | 0.35-0.45 | 0.46-0.55 | 0.28-0.34 |
| Ductility @ 25 °C (cm) | D113 | >100 | >100 | >80 | >120 |
| Solubility in TCE (%) | D2042 | ≥99 | ≥99 | ≥99 | ≥99 |
*ASTM equivalents shown; Chinese GB/T and Russian GOST specify identical procedural envelopes within tolerance bands.
4 | From Refinery to Drum: How A70 Is Made
Vacuum Distillation strips atmospheric residue to VR 370+ cut.
Air-Blown Oxidation (Biturox or Fow-Ox reactors) targets a colloidal “sol-gel” shift that fixes penetration at 70. Operators tune air rate ≈ 0.7 Nm³ kg-¹ feed and reactor temp 240 – 270 °C for Chinese GB grade, vs. slightly lower temps for GOST.
Flash-Down & Storage in spiral-plate heat-exchangers prevents asphaltene flocculation.
Quality Control—each lot is pen- and SP-tested; Brookfield @ 135 °C must sit inside 0.36 ± 0.08 Pa·s for export spec.
Advanced refineries utilise inline FT-NIR for real-time oxidation end-point detection, cutting batch variance by up to 17 %.
5 | Standards Cheat-Sheet
| Jurisdiction | Code | A70 Equivalent | Key Acceptance Window |
|---|---|---|---|
| China | GB/T 15180-2024 | A70 | Pen 65-75 dmm; SP > 48 °C |
| Russia/CIS | GOST 33133-2014 | BND 70/100 | Pen 70-100; SP ≥ 45 °C |
| ASTM (US) | ASTM D946-23 | 60/70 | Pen 60-70; SP 49-56 °C |
| EU (EN) | EN 12591-2025 | 70/100 | Pen 70-100; SP ≥ 46 °C |
For design mixes, always pair the local standard with EN 12697 performance tests (wheel tracking, fatigue, low-temperature cracking) to ensure cross-border conformity.
6 | Market Landscape
6.1 Global Supply
Middle East & North Africa (MENA): Iran and UAE term contracts dominate ISO-tank exports to South-East Asia.
China: Domestic output surged 8 % y-o-y (2024) as Guangxi and Shandong resid upgrading units pivoted to A-grade penetration bitumen.
Russia/Kazakhstan: Post-2023 logistics rerouting via Caspian Sea corridors increased FOB premiums by USD 18 t⁻¹ for BND 70/100. tradekorea.com
6.2 Demand Drivers
| Segment | 2024 Revenue (USD m) | 2030 Proj. (USD m) | CAGR % (25-30) |
|---|---|---|---|
| Road Construction | 39 160 | 57 659 | 6.7 |
| Roofing & Waterproofing | 2 554 | 3 583 | 5.9 |
| Polymer-Modified Bitumen (PMB) | 28 810 | 36 562 | 4.1 |
7 | Core Applications
Dense-Graded Asphalt (AC-16, AC-25): Optimal viscosity stops binder draindown in high-void aggregates.
Surface Dressing & Chip Seal: A70’s moderate SP enhances aggregate retention without early raveling.
Roof Felts & SBS Membranes: Acts as base asphalt before polymer loading (~10 wt % SBS).
Bitumen Emulsions (CSS-1, CRS-2): Lower acid number reduces cationic emulsifier dosage by ~7 %.
Industrial Mastics & Sealants: Used in expansion-joint fillers where flow resistance at 60 °C is critical.
8 | Performance Across Climates
Field trials on AH-70 mixes along the Beijing–Harbin Expressway report rut depths ≤3.2 mm after 20 million ESALs at 38 °C peak, while Siberian sections paved with BND 70/100 displayed no thermal cracking down to −27 °C when modified with 2 % crumb rubber. ResearchGate
9 | Innovation Spotlight
Polymer-Enhanced A70: Adding 4 % Styrene-Butadiene-Styrene lifts softening point to >80 °C, qualifying mixes for PG 76-16 climates.
Warm-Mix Additives: Organic waxes (e.g., Fischer-Tropsch C₃₆-C₅₀) cut plant temperatures by 20 °C, slicing CO₂ by ~12 kg t⁻¹ HMA.
Rejuvenators for High-RAP: Tall-oil fatty amides restore A70 maltenes, allowing 40 % RAP without stiffening penalties.
A 2021 Wiley study on polymer-modified A70 recorded 93 % separation resistance in 72 h high-temp storage, evidencing long-haul stability. Wiley Online Library
10 | Sustainability & Circularity
Life-cycle assessments show that substituting 30 % RAP in A70 pavements can save 1.6 t CO₂-eq per lane-km. Coupled with energy-curable warm-mix chemistry, total GHG cuts reach 22 %. Many agencies now bundle carbon-intensity scoring into tender documents: e.g., the EU’s Level(s) indicator B6 sets a benchmark of ≤350 kg CO₂-eq m⁻² for pavement layers—which a warm A70-RAP blend can meet.
11 | Testing & Quality Assurance
Mandatory Batch Tests
Penetration (D5 / GB T4505)
Softening Point Ring-&-Ball (D36)
Brookfield Viscosity @ 135 °C (D4402)
Ductility (D113)
Rolling-Thin-Film-Oven Ageing (D2872)
Advanced Diagnostics
G/sin δ via DSR* to predict rutting (target ≥1.0 kPa at 70 °C for unaged A70).
BBR Creep Stiffness—for PG mapping.
SARA Fractionation—a 2024 Chinese study links <15 % asphaltenes to lower cracking.
12 | Handling & Logistics
Drummed (180/200 kg): Economical for sub-1 kt lots; ensure vent bungs to prevent thermal bulging.
Jumbo Bags (1 t): Add internal HDPE liners; reheating via low-pressure steam coils recommended.
ISO Bitutainers (25 t @ 180 °C): Most carbon-efficient for inter-regional moves; nitrogen blanketing advisable to curb oxidation.
Always maintain >130 °C during pump-over to avoid viscosity spikes; adopt dual-filter 50 µm + 25 µm mesh to catch coke fines.
13 | Buyer’s Checklist (2025 Edition)
Ask for Dual-Standard COA: e.g., GB/T + ASTM to simplify cross-border acceptance.
Verify Feedstock Source: Paraffinic crudes yield higher wax content—flag for cold-climate jobs.
Inspect Packaging Date: Oxidative hardening begins once drums cool; specify ≤90 days since fill.
Demand Sustainability Disclosure: Scope 1 emissions per tonne; many refiners now publish ISO 14064-3 audited numbers.
Plan Reheating: Budget for 1 kWh t⁻¹ °C; induction-coil kettles recover 7 % energy versus thermal-oil heaters.
14 | Outlook: Smart Roads & Beyond
A70’s balanced rheology makes it the default binder for smart-sensor embedded pavements—its viscosity window allows homogeneous dispersion of piezoelectric chips without segregation. Expect spec amendments in 2026 to include dielectric loss factors for wireless power lanes. Simultaneously, governments pushing net-zero-ready highways are mandating ≥50 % RAP by 2035, something A70’s chemical compatibility facilitates.
Conclusion
From microscale colloidal chemistry to macro-scale infrastructure economics, Bitumen A70 remains a linchpin grade for 21st-century pavement engineering. Whether you’re a specifier seeking longevity, a buyer eyeing cost efficiency, or a policymaker steering sustainability targets, mastering A70’s nuances equips you to build roads—and business models—that endure.
Top 10 Highly-Searched Questions & Answers
| # | Question | Answer (Concise & Actionable) |
|---|---|---|
| 1 | What is the penetration value of Bitumen A70? | Typically 65–75 dmm at 25 °C, indicating medium hardness suited to a wide temperature band. |
| 2 | Is Bitumen A70 the same as 60/70? | Yes in ASTM nomenclature: A70 (Chinese/Russian) aligns with 60/70 penetration grade under ASTM D946. |
| 3 | Can A70 be used in cold climates? | Alone it may crack below −20 °C; add crumb rubber or SBS or blend with softer A90 to meet PG -22 binder grades. |
| 4 | How does A70 compare to polymer-modified bitumen? | PMB offers >80 °C softening point and higher fatigue life; A70 is cheaper and adequate for moderate loads. |
| 5 | What is the shelf life of drummed A70? | Under shade and ≤40 °C ambient, viscosity drift stays <3 % for ≈6 months; rotate stock FIFO. |
| 6 | Does A70 work with warm-mix technologies? | Yes; adding 2 % wax or 0.5 % surfactant cuts mix temps by 15–25 °C without altering gradation specs. |
| 7 | What tests certify A70 quality? | Minimum set: Penetration, Softening Point, Viscosity, Ductility, Thin-Film Oven Ageing, Solubility. |
| 8 | How much A70 is needed per km of highway? | For a 50 mm wearing course at 5 % binder content, ~7.0 t lane-km⁻¹ (4-lane highway ≈28 t km⁻¹). |
| 9 | Is A70 compatible with RAP? | Yes; lab data shows stable viscosity up to 40 % RAP, especially when rejuvenators restore maltenes. |
| 10 | What packaging options are eco-friendly? | Bitutainers cut packaging waste; alternatively, steel drums with ≥70 % recycled content meet many ESG bids. |
References
Modified Bitumen Market Size, Share & Trends Analysis Report – Grand View Research
https://www.grandviewresearch.com/industry-analysis/modified-bitumen-market-reportRequirements to BND 70/100 Road Bitumen as per GOST R 33133-2014 – ResearchGate
https://www.researchgate.net/figure/Requirements-to-BND-70-100-road-bitumen-as-per-GOST-R-33133-2014_tbl2_349632165Thermal Storage Stability of Polymer-Modified A70 Bitumen – Wiley Open Access (2021)
https://onlinelibrary.wiley.com/doi/10.1155/2021/6637999Standard Test Methods for Bitumen Properties – ASTM International
https://www.astm.org/Bitumen and Asphalt Market Insights 2025 – MarketWatch Industry Reports
https://www.marketwatch.com/press-release/bitumen-market-size-share-and-trends-2025-2024-12-21Using Recycled Asphalt Pavement with Penetration-Grade Binders – Transportation Research Board (TRB)
https://trid.trb.org/view/1823034
Prepared by the PetroNaft Co. research team.
