GOST 31108-2020Portland Cement

Four grades, one corridor, and a standard the buyer already knows

In August 2026 Gaz-Trans International was asked a narrow question: what would it take to supply Russian-quality cement to Türkiye at scale, and — in a later phase — onward into the European Union. This dossier is the answer, and it begins by narrowing the field. Russian works produce the full modern range, from CEM 0 through CEM V, alongside a shelf of special binders. Almost none of that range is relevant to a Turkish buyer.

Four grades carry the volume. CEM I 42.5N is the most versatile and the most easily resold. CEM I 42.5R is what precast yards and ready-mix plants ask for when early strength decides the pour cycle. CEM II/A-L 42.5N offers the best balance of cost against performance. CEM III/A 42.5N is the grade that port, tunnel and hydraulic engineering work is written around. Everything that follows exists to explain why those four, and not the others.

The commercial position is equally narrow. Sanctions have closed most of the European outlet for Russian cement, and producers have turned toward the CIS, the Caucasus, Central Asia and the Middle East. Türkiye sits at the near edge of that redirection — a short sea leg from the loading ports, with a construction sector large enough to absorb contracted volume rather than occasional spot parcels.

Cement is not a mixture that dries. It is a hydraulic binder — a finely ground powder that reacts chemically with water, forms new crystalline and gel phases, and hardens under water as readily as in air. Everything a buyer pays for is contained in that reaction and in how fast it proceeds.

The powder is made by burning a precisely proportioned meal of limestone and clay to roughly 1,450 °C. At that temperature the charge partially melts and re-forms as clinker: dark, glassy nodules the size of gravel. Clinker is then ground together with three to five per cent gypsum, which is what stops the cement from flash-setting in the mixer. Mineral additions, where the standard permits them, are inter-ground at the same stage.

Four clinker minerals do the work, and their proportions decide almost everything a specification cares about: how early strength arrives, how much heat is released while it does, and how the hardened paste behaves against sulfate and sea water. A CEM I 42.5R and a CEM III/A 42.5N differ far less in what they contain than in how those contents are balanced and diluted.

Cement production is a sequence of six operations, and only one of them involves fire. The other five exist to make the fire predictable.

Between eighty and ninety per cent of the raw meal is limestone; the balance is clay or shale supplying silica and alumina, corrected with iron ore, sand or bauxite where the deposit falls short. The meal is dried, ground to a flour and homogenised before it enters the preheater tower — a stack of cyclones that recovers heat from the kiln gases and calcines most of the limestone before the material ever reaches the rotary kiln.

In the kiln the charge climbs to roughly 1,450 °C, partially melts and re-forms as clinker. It is then quenched in a grate cooler — quickly, because slow cooling coarsens the crystal structure and costs strength — and stored. Grinding is the last operation and the most electricity-hungry: clinker, gypsum and any permitted mineral addition are milled together to whatever fineness the grade requires.

Modern classification rests on EN 197-1, with which Russia's GOST 31108-2020 is aligned. The older GOST 10178 is steadily disappearing, surviving mainly in the commercial shorthand M400 and M500. Under the modern system every cement belongs to one of five families, and the family is defined by one variable: how much of the binder is clinker, and how much is something else.

That single ratio propagates through everything. More clinker means faster strength, more heat, higher cost and more CO₂. Less clinker — displaced by granulated blast-furnace slag, limestone, fly ash or natural pozzolana — means slower strength, cooler concrete, better resistance to sulfate and sea water, and a lower price. A buyer does not really choose a cement by name; they choose a position on that ratio, and the family name follows.

CEM I 42.5 H, decoded left to right

A cement designation is a compressed specification. Every element in it is load-bearing, and a buyer who reads it correctly rarely needs the data sheet.

Take CEM I 42.5 H. CEM names the material as cement. I places it in the first family — no mineral additions. 42.5 is the guaranteed compressive strength at 28 days, in megapascals. H denotes a normal rate of early strength development. Change that last letter to B, which European practice writes as R, and the same chemistry ground finer becomes a rapid-hardening cement.

In blended cements a second index sits between the family and the class: A or B for how much addition is present, then a letter for what that addition is. CEM II/A-L 42.5N is a Portland-limestone cement at the low addition band. CEM II/B-M 42.5N carries a higher, mixed addition. CEM III/A 42.5N is a blast-furnace cement sitting at the lower slag band of its family.

The figure in a grade designation — 22.5, 32.5, 42.5, 52.5 — is the guaranteed minimum compressive strength in megapascals at twenty-eight days. It is a floor. Works routinely produce above it, and a producer who did not would be gambling an entire consignment on a single test result.

The letter that follows is the other half of the specification, and it is often the half that decides a project's economics. N — written H in Russian designation — means a normal rate of early strength development. R, written B, means high early strength: the same class at twenty-eight days, reached faster over the first two. A precast yard buying 42.5R is not buying more strength. It is buying a shorter mould cycle.

The two are not interchangeable in a contract, and the choice between them is not a matter of preference. Specifying R where N would serve buys a finer grind that the works has to pay for and the structure will never use. Specifying N where the programme needs R gives back a casting cycle every day of the job. Both belong on the shortlist for exactly that reason.

Demand in Türkiye distributes across ready-mix producers, construction companies and infrastructure projects in a pattern stable enough to plan a supply programme against. Two grades dominate, a third takes the cost-sensitive volume, and a fourth serves the works where durability rather than schedule is the binding constraint.

CEM I 42.5R and CEM I 42.5N sit at the top together, and they are not substitutes. The R goes where cycle time is the cost — ready-mix plants, precast beds, contractors carrying liquidated damages on the calendar. The N goes into general construction, housing and commercial work, where it is simply the most reliable and most easily traded cement in the world.

Below them, CEM II/A-L 42.5N absorbs the housing and infrastructure volume that is optimising on cost and on heat of hydration, and CEM III/A 42.5N takes ports, bridges, tunnels, marine structures and hydrotechnical work. That last grade never leads on tonnage and never leaves the list, because nothing else in the range survives sea water for a century.

Eighteen plants, a third of a market, and a map drawn by limestone

Cement is, by volume, one of the largest construction materials produced in Russia. Output is distributed across almost every federal district — enough to supply the domestic market and to make export possible to the CIS, the Caucasus, Central Asia and parts of the Middle East.

Production concentrates where two conditions coincide: limestone deposits and large consumer markets. That geography is fixed — a works cannot be moved closer to a port — and it is the first thing to verify when a specific plant is nominated against a shipment.

CEMROS is the largest player by a wide margin: eighteen cement plants and more than twenty production facilities, producing roughly 20.9 million tonnes a year — about a third of the Russian market. Gaz-Trans International works with this producer on a regular basis. The remaining share is divided among several large producers and independent works.

Cement is a bulk commodity that behaves badly. It is hygroscopic, it flows like a liquid when aerated and like rock when it is not, and it is worthless the moment it meets water. Every packaging decision is therefore a trade between handling cost and the risk of losing the cargo outright.

Bulk is the cheapest format and the reference basis for everything else. Big bags of one or one and a half tonnes are the most popular format among exporters, because they tolerate imperfect port infrastructure and can be broken down on site without a silo. Small sacks are a retail and small-parcel format, not appropriate for deliveries to Türkiye at the volumes discussed here. Containers are the fallback where a berth or a lot size will not support a bulk vessel.

The differences between them are not marginal. Big bags add the bag itself, the filling line, the pallet and the extra handling — and they add all of it to every single tonne. Fifty-kilogram sacks add more again, several times over. That is why sacking is a retail decision rather than a shipping one, and why a seaborne consignment of any size is quoted in bulk unless the receiving end genuinely cannot take it.

A low-margin cargo, and the arithmetic that follows from it

Cement is a low-margin cargo. That single fact explains more about how this trade behaves than any specification in the preceding sections.

A typical delivered cost divides four ways. Production accounts for fifty-five to sixty-five per cent. Rail haulage to the port takes fifteen to thirty. Transshipment — the movement between rail wagon and vessel — takes five to ten. Sea freight takes ten to twenty. Only the first of those four adds value to the material. The remaining three are friction, and together they can consume close to half the landed price.

The consequence is direct. When exporting, the distance between the works and the loading port matters more than the distance between the works and the customer. A plant three hundred kilometres from Novorossiysk will land cement in Türkiye more cheaply than a larger, more modern plant fifteen hundred kilometres inland — and no amount of production efficiency closes that gap.

This dossier does not quote a price. Cement pricing moves with fuel, freight, the construction cycle and the size of the parcel in front of it, and a figure printed in a technical document is out of date before it is read. What can be set out in advance is the structure of a quotation — the variables that decide it, and the terms it will be written on.

Two bases exist in this trade and they must never be confused. FOB names the value at the loading port, with the buyer taking the cargo from the ship's rail onward. CFR names it delivered to a Turkish port, with the sea leg included. The two differ by the entire cost of moving a low-margin cargo across a sea. Any offer issued against this dossier will state both, so the freight component stays visible rather than buried inside a single number.

Everything else is a function of four variables. They are set out below in the order in which they actually move the figure.

The five CEM families cover construction. They do not cover everything Russian works produce. Alongside the standard range, plants make oil-well cement, sulfate-resisting cement, road cement, white cement, hydraulic cement, rapid-hardening cement, low-alkali cement and high-strength cement. Each exists because a specific failure mode had to be designed out.

Oil-well cement is the clearest illustration, and it matters here because it is the point at which the cement trade meets the energy trade. A well is cemented by pumping slurry down the casing and back up the annulus, where it must set into a sheath that isolates the producing zone. If that sheath cracks, the well leaks — between formations, between fracture stages, or to surface.

The requirement is unusual: the set cement must be strong and elastic at the same time. Work on the Bazhenov formation, the largest shale play in the Russian Federation, established a stability window of six to nine gigapascals Young's modulus against thirty-two to thirty-six megapascals compressive strength for horizontal wells subjected to multi-stage fracturing. Conventional blends fell outside that window and were destroyed by frac pressure.

Cement arrives with a mill test certificate stating the grade, the strength class, the composition, the fineness and the results of the works' own testing on the production lot. It is a necessary document and it is not, on its own, sufficient — because the certificate describes the cement that left the silo, not the cement that arrived at the berth.

Two things happen in transit. Moisture is the first and the serious one: cement that has taken up water sets in the hold, in the bag or in the silo, and the loss is total rather than proportional. Contamination is the second — a hold that last carried fertiliser or coal, an auger that last moved a different grade — and it shows up as strength that fails to arrive rather than as anything visible on discharge.

Cement also ages in store. Even under cover it takes up atmospheric moisture and carbon dioxide, and strength falls with time. As a working rule the loss becomes measurable after about three months and material beyond six. A consignment bought against a project that then slips is a consignment quietly losing class in the silo.

This dossier follows from a letter of intent dated 8 August 2026, issued by Gaz-Trans International in response to a request for a long-term, large-scale analysis of cement supply to Türkiye and, in a subsequent phase, to European Union countries.

The terms in that letter are stated plainly and deserve restating the same way. Delivery to the Black Sea port is performed by the supplier. The commercial context is equally plain: sanctions applied to the Russian Federation have redirected producers toward the remaining markets, and the seller has not concealed that this is the reason Türkiye is being approached with a long-term proposition rather than occasional cargoes.

For the buyer, that makes the position legible rather than generous. It is a function of a redirected market, not of goodwill, and it should be evaluated as such — including its durability, which is tied to conditions outside the control of either party.

Every statement in this dossier comes from one of four places, and it is worth separating them, because they do not carry the same weight.

The commercial material — the priority grades, the lot sizes, the packaging formats, the producer ranking and the demand distribution — comes from the letter of intent and its accompanying market note, issued by Gaz-Trans International on 8 August 2026. It is the seller's own statement of position and should be read as such. This dossier deliberately quotes no prices.

The technical material — clinker chemistry, the process sequence, the classification tables and the strength framework — is standard cement science, checked against the reference literature listed below. The oil-well case data is drawn from a peer-reviewed conference paper and is cited where it is used.