60/70沥青出口中国 · Exporting ASTM 60/70 into a Chinese 70# Specification

手中是ASTM D946的60/70产品，买方要的是70号道路石油沥青。针入度不是问题：60/70整体落在70号的60–80区间之内。真正的缺口在于D946证书上根本没有的项目——蜡含量、10°C延度、针入度指数、60°C动力粘度，以及以JTG E20方法而非ASTM方法出具的数据。质量等级同样无法从D946证书判断。结论必须说清楚：60/70证书是起点，不是中国的验收文件。

The material is ASTM D946 60/70 and the buyer wants 70号道路石油沥青. Penetration is not the difficulty: the 60/70 band falls entirely inside the 60–80 band of 70#, so every value that passes D946 also passes the Chinese consistency requirement. The gap is everything a D946 certificate does not carry — wax content (蜡含量) above all, ductility at 10 °C, penetration index (针入度指数), dynamic viscosity at 60 °C, and results produced under the JTG E20-2011 test methods rather than the ASTM designations. A D946 certificate also cannot state a quality class, because the class is decided entirely by properties D946 does not control. The honest conclusion has to be said plainly: a 60/70 certificate is a starting point for a Chinese enquiry, not a Chinese acceptance document.

The arithmetic is simple and it runs in your favour. Under ASTM D946 the grade name is the acceptance band, so 60/70 admits penetration at 25 °C from 60 to 70 tenths of a millimetre and nothing outside it — a window ten units wide. In the Chinese system the number is a nominal penetration with the band written around it, so 70# admits 60 to 80 — a window twenty units wide. The narrow window sits wholly inside the wide one. There is no penetration result that can pass D946 60/70 and fail the 70# consistency requirement.

That is the whole of the good news, and it is worth being clear about how little it settles. Penetration is the first line of the Chinese requirement table and there are a dozen more beneath it. It settles nothing about the quality class either: the 60–80 band is written identically into A级, B级 and C级, so clearing it is not evidence of a class and cannot be offered as one. An exporter who answers a 70# enquiry by pointing at his penetration result has answered the one question that was never in doubt.

Two consequences that are not obvious

First, margin is asymmetric within the band. A 60/70 batch does not sit in the middle of the 70# window; it sits in the lower half of it. A batch measuring 61 dmm has one unit of headroom against the 70# floor of 60, while a batch at 69 dmm has eleven units of headroom above and is nowhere near the ceiling of 80. Since penetration falls as a binder ages, and since drums are reheated at least once between the refinery and the paver, the batches at the bottom of your own grade are the ones exposed. If your production typically runs 61–64 dmm, penetration is still a pass, but it is not the comfortable pass the band arithmetic suggests.

Second, the acceptance result will not be yours. Your figure came from ASTM D5. The Chinese acceptance figure will come from JTG E20-2011 method T 0604, run in the buyer's or the project's laboratory on a sample they draw. The two methods specify the same conditions — 25 °C, 100 g, five seconds — and this is the closest thing to a direct read-across anywhere on the requirement table. But two laboratories testing the same binder do not return the same number to the last unit, and a batch sitting one unit above the 70# floor has no room for that. The material to keep out of a 70# contract is not the material that fails; it is the material that passes by less than the reproducibility of the test.

The full JTG F40-2004 requirement table for 70#, class by class and with the T-number against every line, is set out on the 70号道路石油沥青 page. This page does not repeat it. What follows is the difference between that table and the certificate you are currently holding.

ASTM D946 does not specify wax content. Neither does the typical Middle East export specification built around it. Because no standard in the exporter's world asks for it, nobody ordered the test, no laboratory ran it, and no result was recorded. This is the point most often misread in correspondence with a Chinese buyer: the wax figure is not missing from your certificate the way a line can be accidentally left off a form. It has never existed for your material.

Four consequences follow, and they are practical rather than chemical. The chemistry, the limits and the crude-source question are covered on the wax content page; what follows is what it means for somebody holding 60/70 production and an enquiry.

1. You cannot answer the question from stock data

When a Chinese buyer asks for 蜡含量, there is nothing to look up. Sending the technical data sheet does not answer it, sending the last three certificates of analysis does not answer it, and sending a typical value from a refinery brochure answers it with a number that was not measured on your material. The only honest replies are a measured result or an admission that the test has not been run. The second reply, given early, costs far less than the first reply given carelessly.

2. The laboratory has to run the right test

Chinese acceptance measures wax by the distillation method under JTG E20-2011 method T 0615. A laboratory that runs ASTM bitumen work daily does not necessarily hold the apparatus for it or report against that method number. When commissioning the work, ask whether the laboratory runs T 0615 specifically. A reply along the lines of yes, we can test wax content, is not the same answer, and a result produced by some other route reported under the Chinese method number is worse than no result at all.

3. The number is a fact about your source, not about the grade

Wax content is set by the crude slate and the refining route. It is not a property of the designation 60/70 and nothing done to the drums changes it. Once measured, the figure is fixed for that source, and it partitions the Chinese market for you before any commercial discussion begins: below 2.2 % and A级 is open, between 2.2 % and 3.0 % and the conversation moves to B级, between 3.0 % and 4.5 % and only C级 remains, above 4.5 % and the material sits outside the JTG F40 road petroleum asphalt table at this grade altogether. The quality class page sets out what each of those positions permits.

4. Measure once per source, not once per enquiry

Because the result belongs to the source rather than the shipment, the sensible sequence is to measure it once, early, for each production origin you can actually supply from, and to treat the figure as standing market intelligence. It is the cheapest information available to anybody selling into China, and it decides which enquiries are worth pursuing. The corollary matters too: if you can draw from more than one refinery, one wax result does not cover the second, and a certificate showing a good wax figure for one origin is not evidence for a cargo loaded from another.

The quality class of a Chinese paving grade is not decided by penetration, softening point, flash point or solubility. It is decided by wax content, ductility at 10 °C, penetration index and the requirements on the residue after film oven ageing. Set that list against a D946 certificate and every single entry is either absent or measured differently. That is why the honest answer to a class question is not probably A级 or at least B级. It is that the class has not been determined, and cannot be, until three or four tests are run.

What the class then means — a permission tied to the highway class and the pavement layer rather than a marketing tier — is set out on the A级、B级、C级 page, together with the layer-by-layer matrix. Below is only the part that concerns somebody converting an ASTM file.

15 °C 与 10 °C 延度 · The two ductility results you do not have

Your certificate reports ductility at 25 °C, because that is the temperature ASTM D946 specifies, and it very probably reports a comfortable 100 cm or more. JTG F40 asks for 100 cm at 15 °C, and then asks again at 10 °C against a limit that tightens by class.

Why a 25 °C result cannot stand in for a 15 °C one is explained on the 70# page and is not argued again here. What matters on the exporter's side of the transaction is narrower and entirely practical: the substitution is not available to you, no correlation factor will be accepted in its place, and the only way to find out where your material stands is to buy the test.

Two things follow for anybody placing that order. The first is to order both temperatures in the same instruction. They run on the same apparatus, the marginal cost of the second determination is small against the first, and a seller who orders only 15 °C because that is the line with a fixed limit will be back at the same laboratory a fortnight later when the buyer names a class. The second is that the 10 °C order cannot be placed at all until two facts arrive from the buyer. Its limit moves with the quality class and with the climate zone assigned to the project, so a laboratory instructed to test 10 °C ductility for 70# can produce a number but cannot produce a pass or a fail. The zone is a three-part code (气候分区) belonging to the project location, and how it is read is set out on the climate zone page. In practice this is the line that decides how the enquiry is handled: an enquiry that arrives with the class and the code attached can be converted into a test order the same day, and one that arrives without them cannot be, whatever the seller is willing to spend.

针入度指数 · The calculation that has to be done the right way

The penetration index bounds temperature susceptibility in both directions, and the window JTG F40 sets at A级 is -1.5 to +1.0. Because the index is one of the properties the class table separates on, that window is not the one every class is judged against; it is relaxed below A级. Read the row for the class you intend to quote out of the edition of the specification cited in the project documents rather than treating a single window as covering the grade. The more common error is upstream of that: PI is a calculated quantity, not a measured one, and exporters go wrong on how it is calculated.

The Chinese route obtains PI by linear regression of the logarithm of penetration against temperature, using penetration measured at several temperatures — 15 °C, 25 °C and 30 °C, with a further point added where the fit requires it — and it sets a minimum quality on that regression, so three loosely scattered results do not produce a usable index. That means real laboratory work: additional T 0604 determinations at temperatures nobody has ever asked your refinery for.

There is a second, older route that derives a penetration index from penetration and ring-and-ball softening point. It is a different calculation producing a different quantity, and it is attractive because both inputs are already on your certificate. Reporting a number obtained that way under the same three letters, against a specification that calls for the regression, produces a figure that looks correct and did not come from the required procedure. An acceptance laboratory recalculating from its own penetrations will find the discrepancy quickly, and the discussion that follows will be about the certificate rather than about the binder.

老化后残留 · The one ageing property you have, measured another way

ASTM D946 does control ageing: it sets a retained penetration floor after the thin film oven test to ASTM D1754. So this is the one class-determining area where a D946 file is not simply blank. It is still not transferable. JTG F40 works from T 0610 (rolling thin film oven) or T 0609 (thin film oven), holds mass change within ±0.8 %, requires a retained penetration ratio of at least 61 % for 70# A级, and adds a residue ductility line that tightens by class and zone. Different ageing procedure, different limits, and an extra property on top. A retained penetration figure from a D1754 run is evidence that the binder ages reasonably; it is not evidence of a Chinese pass, and the contract has to name which ageing regime the limits refer to.

What this adds up to

Four class-determining property groups, four gaps. A 60/70 exporter is not one test away from a class claim; he is a small test programme away from knowing which class is even available to him. That programme is cheap relative to a cargo and it is the subject of the next section.

An ASTM D946 certificate proves that the material is 60/70. It does not prove that the material is 70#. It cannot state a quality class, because the class is decided entirely by properties D946 does not control. And it was produced under a test regime other than the one a Chinese acceptance laboratory will use. It is the first document in the file, not the file.

That is not a judgement on the binder. A 60/70 cargo can be excellent material, properly made and honestly certified, and still be unable to answer a single one of the four questions a Chinese project asks. The certificate is doing exactly the job it was designed to do; it was simply designed for a different market.

四种结果 · The four outcomes of the test programme

Once the missing tests are run, one of four things is true, and it is worth knowing in advance what each of them means commercially.

• Everything clears the A级 lines. You have a 70# A级 position and, more valuable than the position, a technical file that supports it line by line. This is the outcome to plan for and it is not the most common one.
• Wax lands between 2.2 % and 3.0 %, or the low-temperature ductility falls short at A级. A级 closes and B级 opens. This is a redirection rather than a loss: B级 is admitted in the lower layers of expressways and class-1 highways and in every layer of the classes below them, which is a substantial share of the paving work being done. The permitted-use matrix is on the quality class page, and it is worth reading before deciding the enquiry is dead.
• Flash point or solubility falls between the ASTM floor and the Chinese floor. This is the outcome exporters least expect, because they have been told the class system is the difficult part. It is not a class problem: 260 °C and 99.5 % are identical in A级, B级 and C级, so a genuine 252 °C flash point or a genuine 99.2 % solubility fails at every class and no reclassification recovers either. A material that is entirely compliant with ASTM D946 can fail 70# outright on these two lines alone.
• Wax above 4.5 %. The material sits outside the JTG F40 road petroleum asphalt table at this grade. That is a sourcing conclusion rather than a negotiating position, and the useful response is to find out what the other production origins available to you measure.

结果出来之前怎么答复 · What to say while the tests are still pending

The test programme takes time, and the enquiry does not wait for it. This is the point at which most 60/70 conversions are lost, and they are lost in the reply rather than in the laboratory. Three replies are available and they are not equally survivable.

The first is to send the D946 certificate and the data sheet and let the buyer draw his own conclusion. It buys a few days and it costs the transaction later, because the missing lines do not become less missing and the buyer eventually discovers that the answer he was given was a document about a different market. The second is to fill the gaps with typical values from a refinery brochure. That is worse: a typical wax figure is a statement about somebody's production average and not about the drums on offer, and once it is written down it becomes the number the material is judged against.

The third is the only one that holds. Say which lines are measured on the batch and give them; say which lines are not measured and say plainly that they are not; name the tests that have been commissioned, the methods they will be run to and when the results are expected; and ask for the class and the zone code so that the 10 °C order can be placed. That reply is shorter than either of the others and it changes what is being negotiated — from whether the seller's paperwork can be believed to when the file will be complete. A buyer who is told in week one that wax has not yet been measured will wait for the number. A buyer who discovers in week six that it was never measured will not.

One caution on the temptation to compete on price during that wait. Imported cargo into China does not fill a national shortage — the way import demand actually arises is the subject of the market hub page — so the discount is being offered into a market that already has an alternative with a complete technical file. A price concession made to cover an incomplete file buys nothing, because it is the one concession that does not survive a failed acceptance test. Spend the money on the tests instead; it is a fraction of the concession and it is the only version that closes the enquiry.

If the object is instead to work out which Chinese numbered grade an ASTM or EN grade should be aimed at in the first place, that mapping question is handled on the grade equivalence page, and the ASTM grade itself is documented on the Bitumen 60/70 page.