Bitumen 60/70 vs 50/70 penetration grade difference is a hardness distinction: 60/70 has a higher penetration number (softer), 50/70 a lower one (harder), as measured by the ASTM D5/D5M and AASHTO T 49 needle-penetration test. Both are among the five standard grades (40–50, 60–70, 85–100, 120–150, 200–300 dmm) referenced across BS EN 12591 and ASTM D946/D946M specifications. BHD Group supplies bitumen 60/70 through BHD Chemical, the grade confirmed in its own approved product fact sheet.
Bitumen 60/70 vs 50/70 penetration grade difference comes down to hardness: both are standard paving grades measured by the same penetration test, with 60/70 penetrating deeper (softer) than 50/70 (harder) at 25°C. The distinction matters to road engineers and procurement teams because grade selection affects mix design, climate suitability and compliance with the specification named on a project's bill of materials. This guide explains what the numbers mean, where each grade is specified, and what to check before placing an order.
Who this guide is for
This page is written for the people who actually decide which drum of bitumen shows up on site: road and paving contractors comparing grades against a project spec; asphalt plant managers matching binder to local climate and traffic loading; and procurement or technical buyers who need to confirm a supplier's grade against a named standard before signing a purchase order. Each of these readers gets a section below that answers their specific question.
What "penetration grade" actually measures
Penetration grade is not a brand name or a marketing tier. It is a laboratory measurement of how far a standard needle sinks into a bitumen sample under fixed load, time and temperature, expressed in tenths of a millimetre (dmm). The test method is set out in ASTM D5/D5M (ASTM International, 2020), and the AASHTO equivalent — AASHTO T 49-15 (AASHTO, 2019) — is identical to the ASTM method apart from a substitution of AASHTO T 53 for ASTM D36 in referenced provisions.
A higher penetration number means a softer binder; a lower number means a harder one. That single fact is the entire basis for the 60/70 vs 50/70 comparison.
Where the grade boundaries come from
Penetration grading is not specific to one region or one buyer's preference. According to the IARC Monographs (NCBI Bookshelf, undated), bitumens are classified into five standard penetration grades, from hardest to softest: 40–50, 60–70, 85–100, 120–150 and 200–300 dmm. ASTM D946/D946M lists the same five grades for penetration-graded asphalt binder used in pavement construction, per ASTM International (2020). 50/70 sits between the 40–50 and 60–70 bands and is widely used in European specification systems alongside 60/70.
60/70 vs 50/70: the comparison
| Property | Bitumen 60/70 | Bitumen 50/70 |
|---|---|---|
| Relative hardness | Softer of the two — higher penetration number | Harder of the two — lower penetration number |
| Test method | ASTM D5/D5M or AASHTO T 49 penetration test | ASTM D5/D5M or AASHTO T 49 penetration test |
| Grade family | One of five standard penetration grades (IARC/NCBI, undated) | Falls between the 40–50 and 60–70 standard bands |
| Governing specification example | Named in penetration-grade specs such as ASTM D946/D946M | Common in EN-system specifications used alongside EN 12591 grades |
60/70 is the grade an approved BHD Group fact sheet (facts/bitumen.yaml, penetration_25c: 60/70) confirms is supplied by BHD Chemical. BHD does not currently hold an approved fact for a 50/70 product, so this guide covers the grade comparison in general terms without attributing 50/70 figures to BHD's own supply.
Standards that define paving-grade bitumen
Buyers checking a quote against a specification should know which document is being referenced. BS EN 12591:2009 (BSI Knowledge, 2009) provides a framework for specifying bitumen properties and test methods for bitumens used in roads, airfields and other paved areas, including requirements for evaluation of conformity. The Swedish adoption of the same standard, SS-EN 12591:2009 (SIS, 2009), is listed with status "Valid" and notes that industrial bitumens are specified separately under EN 13305. The Serbian national adoption, SRPS EN 12591:2013 (Institute of Standardization of Serbia, 2013), was published on 28 February 2013 and remains active with an effective date of 30 November 2022.
For a wider industry view of bitumen production, chemistry, use and occupational exposure, IS-230 (Asphalt Institute & Eurobitume, 2024) is a joint reference document covering the full picture, not just grading.
For road and paving contractors: matching grade to the project spec
Contractors should treat the penetration grade on a project drawing as a fixed requirement, not a negotiable line item. If the spec calls for 60/70 and a supplier offers 50/70 (or vice versa), that is a different material, not an equivalent substitution. Confirm the grade against the named standard — EN 12591, ASTM D946/D946M, or the applicable national adoption — before the binder is ordered, not after it arrives on site.
For asphalt plant managers: climate and traffic loading
Historical field trials illustrate why grade choice is climate-dependent. A Vermont Agency of Transportation (1985) ran a field trial comparing 60/70 penetration asphalt against 85/100 penetration asphalt on U.S. Route 302, reported in January 1985 — a reminder that grade performance has long been tested in service, not assumed from the lab number alone. Plant managers weighing 60/70 against 50/70 should apply the same discipline: confirm which grade the regional specification and expected traffic loading actually call for.
For procurement and technical buyers: verifying a supplier's claim
When a supplier states a penetration grade, ask which standard and test method back that number. A grade claim with no cited method — ASTM D5/D5M, AASHTO T 49, or the relevant EN 12591 national adoption — is not verifiable. BHD Chemical supplies bitumen 60/70, the grade confirmed in its own approved fact sheet, and states it plainly rather than leaving the grade to inference.
What to check before you order
- Confirm the exact penetration grade required by the project specification (60/70, 50/70, or another standard grade)
- Ask the supplier which test method and standard the stated grade is certified against
- Check whether the applicable regional standard is EN 12591, a national EN adoption, or ASTM D946/D946M
- Verify the grade quoted matches the grade on the certificate of analysis, not just the sales quote
- Confirm delivery volume, packaging (drums or bulk) and delivery date against the project schedule
- Ask for the origin of the bitumen and whether it is Turkish-origin, if origin matters to the project's sourcing requirements
- Clarify whether the order is being placed with BHD Chemical directly, and who at BHD Group is accountable for the shipment
Quick facts
- Penetration grade is measured by a standard needle-penetration test at 25°C, expressed in dmm.
- The five standard penetration grades run 40–50, 60–70, 85–100, 120–150 and 200–300 dmm, from hardest to softest.
- 60/70 is softer (higher penetration number) than 50/70 (lower penetration number).
- ASTM D5/D5M and AASHTO T 49 are the standard test methods that define these grades.
- BS EN 12591:2009 and its national adoptions (e.g. Sweden's SS-EN 12591:2009, Serbia's SRPS EN 12591:2013) are the European framework for paving-grade bitumen specification.
- BHD Group supplies bitumen 60/70, the grade confirmed in its own approved product fact sheet.
Working with BHD Group
BHD Group operates two divisions — BHD Chemical and BHD Sourcing — one accountable house behind both. Bitumen 60/70 is supplied through BHD Chemical, on spec and on time, alongside the wax range that is the business's headline: Paraffin Wax, Petroleum Jelly and Slack Wax. This bitumen 60/70 vs 50/70 penetration grade difference guide is intended as a reference for buyers evaluating grade specifications before they place an order — an overview to work from, not a substitute for the certificate of analysis. Buyers with a specific project spec or delivery timeline are welcome to raise it directly with BHD Chemical.
Sources
- Asphalt Institute & Eurobitume (2024) — IS-230, The Bitumen Industry: A Global Perspective, 4th Edition — link
- BSI Knowledge (2009) — BS EN 12591:2009, Bitumen and bituminous binders. Specifications for paving grade bitumens — link
- Swedish Institute for Standards (SIS) (2009) — SS-EN 12591:2009 — link
- ASTM International (2020) — ASTM D946/D946M-20, Standard Specification for Penetration-Graded Asphalt Binder for Use in Pavement Construction — link
- ASTM International (2020) — ASTM D5/D5M-20, Standard Test Method for Penetration of Bituminous Materials — link
- AASHTO (2019) — AASHTO T 49-15, Standard Method of Test for Penetration of Bituminous Materials — link
- IARC / NCBI Bookshelf (undated) — Bitumens and Bitumen Emissions, IARC Monographs Vol. 103 — link
- Vermont Agency of Transportation (1985) — Experimental Use of 60/70 Penetration Asphalt as Compared to 85/100 Penetration Asphalt on U.S. Route 302, Initial Report 85-1 — link
- Institute of Standardization of Serbia (2013) — SRPS EN 12591:2013 — link
Frequently asked questions
What is bitumen 60/70 vs 50/70 penetration grade difference?
It is the difference in hardness between two standard paving-grade bitumens, measured by the penetration test: 60/70 penetrates deeper (is softer) and 50/70 penetrates less (is harder) at 25°C. Both fall within the five standard penetration grades — 40–50, 60–70, 85–100, 120–150 and 200–300 dmm — recognized in specifications such as ASTM D946/D946M and BS EN 12591.
How does bitumen 60/70 vs 50/70 penetration grade difference work?
A standard needle is pressed into a bitumen sample under fixed load, time and temperature per ASTM D5/D5M or the equivalent AASHTO T 49 test, and the depth it sinks (in tenths of a millimetre) sets the grade. A deeper penetration reading places the bitumen in the softer 60/70 band; a shallower reading places it in the harder 50/70 range. The grade a supplier quotes should always be traceable to this test and a named standard, such as BS EN 12591 or its national adoptions.
What are the benefits of bitumen 60/70 vs 50/70 penetration grade difference?
Knowing the difference lets buyers match the binder to the project specification and expected climate or traffic loading rather than treating grades as interchangeable. It also gives procurement teams a concrete basis — the penetration test and the standard it is certified against — for verifying a supplier's grade claim before an order is placed. BHD Chemical states its bitumen grade, 60/70, against this same standard basis rather than leaving it to inference.
Why buyers work with BHD Group
Two divisions operate under a single accountable house. There is no handoff between a trading desk and a sourcing desk that leaves a buyer chasing an answer — one team owns the order from enquiry to delivery.
About