Ready-Mix Volume, Weight & Cost Calculator — 2026 Specifications & Pricing Guide
C35/45 concrete is a high-strength structural concrete grade widely specified across the United Kingdom for demanding applications in multi-storey buildings, infrastructure, precast manufacture, marine engineering, and post-tensioned construction. Designated as RC35 under the BS 8500 named mix system, C35/45 delivers a characteristic compressive cube strength of 45 N/mm² at 28 days — 80% stronger than the standard GEN3 / C20/25 used in domestic foundations and 12.5% stronger than C32/40 for the most heavily loaded structural elements and severe exposure environments.
The designation C35/45 follows the Eurocode convention: C for concrete, 35 for the characteristic cylinder strength in N/mm², and 45 for the characteristic cube strength in N/mm² — both measured at 28 days. In UK structural design to Eurocode 2 (BS EN 1992), the cylinder strength of 35 N/mm² is used directly in design equations for flexure, shear, and compressive stress, while the cube strength of 45 N/mm² is the value confirmed by quality control cube tests at the batching plant and on site. C35/45 sits at the upper end of the standard ready-mix concrete grade range — above it, concrete grades transition into the high-performance and ultra-high-performance categories that are predominantly the preserve of specialist precast manufacture and major infrastructure projects.
In 2026, the price of C35/45 concrete per cubic metre in the UK ranges from approximately £160 to £215 per m³ for standard ready-mix delivered by transit mixer, rising to £185–£260/m³ in London and the South East. The higher cost compared to C32/40 reflects the further increased cement content (360 kg/m³ minimum), a tighter maximum water-cement ratio of 0.45, the near-universal requirement for high-performance superplasticiser admixtures, and the more rigorous quality assurance and conformity testing protocols associated with this strength class. Understanding when C35/45 is the correct — and necessary — specification, and what the total delivered cost will be for your specific project, is the purpose of this guide.
C35/45 concrete is not a general-purpose grade — it is a deliberately chosen specification for applications where structural demands, durability requirements, or a combination of both exceed what lower grades can reliably deliver. The most common applications for C35/45 in UK construction in 2026 are:
Structural columns in multi-storey buildings: In commercial, residential, and mixed-use buildings of five storeys and above, the cumulative gravity loads from floors, walls, cladding, and occupants can generate column axial forces of several megawattons (MN). Using C35/45 rather than C30/37 in heavily loaded columns allows the structural engineer to specify a smaller column cross-section — reducing the visual intrusion of columns into usable floor space and simplifying the architectural layout. On a typical multi-storey scheme, the saving in column area from upgrading to C35/45 can easily justify the £20–£30/m³ concrete premium through increased net lettable or saleable area.
Post-tensioned slabs and flat slabs: Post-tensioned concrete construction — where high-strength steel tendons are tensioned after the concrete has hardened, placing the concrete into beneficial compression — requires concrete strong enough to sustain the high local bearing stresses around tendon anchorages without local crushing. C35/45 is the minimum grade commonly used for post-tensioned ground floor slabs and suspended flat slabs in UK commercial and residential construction, with some engineers specifying C40/50 for the most slender slab designs. The higher compressive strength also improves the slab's resistance to punching shear around column heads — one of the critical design checks for flat slab construction.
Transfer beams and transfer structures: In buildings where columns or walls from upper floors are stopped and their loads transferred to fewer, larger columns at a lower level, the transfer structure must carry enormous concentrated loads. Transfer beams and transfer slabs in C35/45 or C40/50 allow these elements to be designed with manageable depths while maintaining adequate structural capacity and durability over the building's full design service life of typically 50–100 years.
Bridge decks and infrastructure elements: Highway and railway bridge decks in the UK are routinely specified in C35/45 or C40/50 under the requirements of the Design Manual for Roads and Bridges (DMRB) and Network Rail standards. The combination of high traffic loading, de-icing salt chloride attack, freeze-thaw exposure, and the very long design service life required for public infrastructure (typically 120 years for highway bridges) demands the highest practical concrete durability, achieved through the C35/45 strength class with appropriately blended cements and maximum cover to reinforcement.
Precast concrete elements: Prestressed precast concrete — including standard pretensioned bridge beams (Y-beams, M-beams), floor beams, double-tee slabs, and architectural cladding panels — is predominantly manufactured in C35/45 or higher. The controlled factory environment of a precast plant allows the tight quality control required for C35/45 to be achieved consistently and economically, and the high early strength of C35/45 with CEM I 52.5N cement allows prestress to be transferred to the concrete in as little as 12–16 hours — enabling rapid demoulding and turnaround of the casting beds.
Bored and driven concrete piles: Concrete bored piles — ranging from 300mm diameter mini-piles to 1,500mm diameter large-diameter bored piles — are commonly specified in C35/45 to provide adequate structural capacity within the pile cross-section while resisting the harsh chemical conditions encountered below ground, including groundwater aggressivity, chloride from saline groundwater, and physical damage during installation. The high cement content and low water-cement ratio of C35/45 also reduces the permeability of the pile concrete, limiting the rate of chloride ingress to the reinforcement over the pile's design life.
The price of C35/45 concrete per cubic metre in the UK in 2026 is driven by the combination of high cement content, specialist admixture requirements, tighter batching tolerances, and more rigorous quality assurance compared to standard domestic concrete grades. Several factors contribute to the final delivered price on any specific project:
Full ready-mix transit mixer (6m³ minimum): £160–£215 per m³ for standard RC35 / C35/45 concrete across most of England. The mid-point of approximately £185/m³ is a useful planning figure for the Midlands and North of England. London prices consistently reach £200–£245/m³ due to higher operating costs, congestion charges, and the greater proportion of specialist cement mixes required for London's complex urban ground conditions. Delivery within the standard radius is typically included in the per-m³ price, with mileage surcharges applying beyond approximately 20–30km from the batching plant.
Cement and admixture cost drivers: At 360 kg/m³ minimum cement content with a high-performance superplasticiser required to achieve adequate workability at maximum w/c 0.45, the raw material cost of C35/45 concrete is meaningfully higher than lower grades. Cement prices in 2026 remain elevated compared to the 2019–2021 baseline — energy costs for cement clinker manufacture, which involves heating limestone and clay to approximately 1,450°C in a rotary kiln, have not fully retreated from the 2021–2023 energy crisis peaks. This structural cost increase filters through to every ready-mix grade, but disproportionately affects high-cement-content mixes like C35/45 and above.
Quality assurance premium: C35/45 concrete must be supplied from a QSRMC (Quality Scheme for Ready Mixed Concrete) or BSI-assessed batching plant with full traceability of all constituent materials, regular third-party auditing, and comprehensive plant testing. The administrative and quality system overhead of maintaining these certification schemes adds approximately £3–£8/m³ to the production cost of higher-grade concretes, compared to standard GEN3 production which is less intensively monitored.
Short-load charges and minimum order penalties: As with all ready-mix grades, the minimum order for a standard transit mixer delivery of C35/45 is typically 6m³. Short-load surcharges for orders below this minimum are typically £60–£150 per delivery for C35/45 — higher than for standard GEN3, reflecting the higher value of the concrete and the greater relative cost to the plant of batching a small quantity of a high-specification mix.
Ready-Mix Suppliers — C35/45 UK 2026: Hanson Concrete UK | Aggregate Industries | Tarmac Ready Mix | CEMEX UK | Technical standards: BSI Group | Structural guidance: The Concrete Centre
A standard C35/45 / RC35 concrete mix design for UK structural applications requires precise proportioning and careful quality control at every stage of production. A typical C35/45 mix per cubic metre contains approximately: 360–400 kg of Portland cement or blended cement binder (CEM I 52.5N for precast and early-strength applications; CEM II/B-V with PFA or CEM III/A with GGBS for in-situ structural pours requiring enhanced durability); 140–158 litres of free water; 580–650 kg of fine aggregate (zone 2–3 sharp sand); 1,020–1,110 kg of 20mm or 14mm coarse aggregate; 3–6 litres of high-range water reducer (superplasticiser); and optionally 0.1–0.3 litres of air-entraining admixture for freeze-thaw exposed applications.
The water-cement ratio of C35/45 is a maximum of 0.45 — significantly tighter than the 0.50 permitted for C32/40 and the 0.65 used for standard GEN3 / C20/25 domestic foundations. At this very low water-cement ratio, the concrete without admixture would be far too stiff to place and compact reliably on site. High-range water reducers (HRWRs or superplasticisers) — typically polycarboxylate ether (PCE) based in 2026 — are therefore an essential rather than optional ingredient in every C35/45 mix, capable of reducing the water demand by 20–30% while maintaining adequate workability for pump placement and vibration compaction.
The mean strength of a well-controlled C35/45 mix is typically 52–58 N/mm² cube strength at 28 days — significantly above the characteristic 45 N/mm² specification. This excess of mean over characteristic strength is a deliberate feature of the statistical quality control system in BS 8500: it ensures that 95% of individual cube test results fall above the characteristic strength even when production variability is taken into account. Reputable ready-mix suppliers will be able to provide historical test data demonstrating their mean strength and standard deviation for the C35/45 mix they produce, which is a useful indicator of production quality and consistency.
Post-tensioned concrete construction has become increasingly prevalent in UK commercial and residential development over the past two decades, and C35/45 concrete is the standard minimum specification for most UK post-tensioned slab and beam applications. In post-tensioned construction, high-strength steel tendons — typically 12.9mm diameter 7-wire strand with a characteristic tensile strength of 1,860 N/mm² — are threaded through plastic duct within the formwork before the concrete is poured. After the concrete reaches a minimum specified strength (typically 25–30 N/mm² cube, approximately 3–5 days after casting), the tendons are stressed using hydraulic jacks and locked off at the slab edge. This places the concrete in compression, counteracting the tensile stresses from gravity loading and allowing significantly thinner slabs — typically 225–275mm rather than 350–450mm for an equivalent conventionally reinforced flat slab — over the same span.
The use of C35/45 in post-tensioned construction is important for two primary reasons. First, the high compressive strength ensures that the concrete can sustain the very high local bearing stresses at tendon anchorages — typically 200–400 N/mm² concentrated over a 150mm × 150mm bearing plate — without local crushing or spalling. Second, the very low permeability of C35/45 concrete (resulting from the low water-cement ratio and high cement content) provides excellent resistance to chloride ingress to the tendons — critical because PT tendon strands are far more sensitive to corrosion than conventional mild steel reinforcement due to the high stress under which they operate.
The UK precast concrete industry relies heavily on C35/45 and higher strength concrete grades to produce structural elements that are both efficient in cross-section and sufficiently durable for long service lives in exposed or aggressive environments. Standard pretensioned precast bridge beams — Y-beams, U-beams, T-beams, and box beams — are manufactured in C35/45, C40/50, or even C45/55 depending on the span, loading, and environment. The controlled factory conditions of a precast plant allow the low water-cement ratio of C35/45 to be achieved consistently and the concrete to be steam-cured at elevated temperatures (typically 40–65°C) to accelerate strength gain, enabling tendon stressing in as little as 12–18 hours.
For architectural precast cladding panels, staircases, and facades, C35/45 provides the combination of high strength (enabling thin cross-sections with good edge definition), low permeability (resisting staining and deterioration on exposed surfaces), and consistent quality (essential for achieving the precise finish demanded by architects). The use of CEM I 52.5N cement in precast production — chosen for its rapid early strength development rather than its long-term durability credentials — is appropriate for the factory environment but would not be the first choice for in-situ marine or aggressive-environment concrete, where blended cements with GGBS or PFA provide better long-term chemical resistance.
The quality assurance requirements for C35/45 concrete are significantly more rigorous than those for standard domestic grades. Under BS 8500-1 and BS EN 206, concrete of this strength class must be produced by a plant operating under a certified quality management system — either the QSRMC (Quality Scheme for Ready Mixed Concrete) or an equivalent BSI-assessed scheme. These schemes involve: third-party auditing of the batching plant at least twice per year; regular testing of all constituent materials; daily or weekly plant cube testing to monitor production variability; maintenance of a documented quality system covering all aspects of concrete production; and provision of a declaration of performance (DoP) or equivalent conformity documentation with each delivery.
On site, the standard quality control protocol for C35/45 structural pours involves: taking cube samples from the delivered concrete per BS EN 12350-1 (minimum one set of six cubes per 50m³ or per day's pour — three tested at 7 days, three at 28 days); checking the slump of each truck load on arrival; recording the time of batching from the delivery ticket and rejecting any load that exceeds the 90-minute limit; and retaining all delivery tickets in a permanent project file. For post-tensioned slabs, additional in-situ concrete testing is typically required to verify that the minimum stressing strength has been achieved before tendon stressing begins — this may involve cube tests at 3 or 4 days, or the use of maturity monitoring equipment embedded in the slab.
| Region | C35/45 / RC35 per m³ | C32/40 / RC32 per m³ | C40/50 / RC40 per m³ | Notes |
|---|---|---|---|---|
| London | £200–£245 | £185–£225 | £218–£268 | Highest in UK — ULEZ / congestion / access surcharges |
| South East England | £190–£228 | £175–£210 | £208–£250 | High demand; competitive but premium pricing |
| South West England | £178–£215 | £165–£198 | £195–£235 | Rural mileage surcharges add cost on remote sites |
| East Anglia | £172–£208 | £160–£192 | £188–£228 | Good plant coverage in most urban areas |
| Midlands (national avg.) | £165–£205 | £155–£188 | £182–£222 | Close to UK average — good supplier competition |
| North West England | £162–£200 | £152–£185 | £178–£218 | Competitive market with multiple major suppliers |
| Yorkshire & Humber | £160–£198 | £150–£182 | £175–£215 | Good availability and pricing across the region |
| North East England | £158–£192 | £148–£178 | £172–£210 | Lowest prices in England for C35/45 |
| Wales | £165–£208 | £155–£190 | £182–£228 | Rural areas significant surcharges — plan delivery carefully |
| Scotland (Central Belt) | £162–£200 | £150–£185 | £178–£218 | Good supply in Glasgow / Edinburgh corridor |
| Scotland (Highlands / Islands) | £200–£270 | £185–£250 | £220–£295 | Remote surcharges significant — precast or site-mix may be preferred |
| Northern Ireland | £158–£192 | £148–£178 | £172–£210 | Competitive local market with good plant coverage |
Prices are indicative May 2026 trade account estimates for standard RC35 / C35/45 ready-mix. Specialist blended cement mixes for aggressive exposure (marine, very high sulfate) typically add £10–£22/m³. Cash / retail prices 12–22% higher. Always obtain at least two quotes — prices can vary 20–28% across the UK.
| Method | Min. Order | Price per m³ (2026) | Delivery / Mobilisation | Short Load Fee | Best For |
|---|---|---|---|---|---|
| Ready-mix transit mixer | 6m³ (typical) | £160–£215/m³ | Included up to ~25km | £60–£150 if <6m³ | In-situ structural pours >4m³ — columns, beams, slabs |
| Mini-mix (small drum truck) | 0.25m³ | £225–£300/m³ | £32–£70 fixed | None | Small column bases, isolated pours 0.25–3m³ |
| Volumetric / on-site mix | None | £188–£240/m³ | £45–£100 mobilisation | None — pay per m³ used | Precise volumes 1–10m³, isolated elements, no waste |
| Precast plant supply | Full element | £185–£260/m³ equiv. | Delivery + crane included | N/A | Beams, piles, panels, stairs — factory control preferred |
| Pump + ready-mix combined | 6m³ concrete | £160–£215/m³ + pump | Pump: £450–£1,400/day | As per transit mixer | Virtually all in-situ C35/45 structural pours |
| Grade | BS 8500 Name | Cube Strength | Cylinder Strength | Max w/c | Min. Cement (kg/m³) | Price per m³ (2026) | Typical Use |
|---|---|---|---|---|---|---|---|
| C20/25 | GEN3 | 25 N/mm² | 20 N/mm² | 0.65 | 240 | £125–£160 | Strip foundations, oversite, garage slabs |
| C25/30 | RC25 / FND2 | 30 N/mm² | 25 N/mm² | 0.60 | 280 | £135–£175 | RC slabs, mildly aggressive ground (AC-2) |
| C28/35 | RC28 / FND3 | 35 N/mm² | 28 N/mm² | 0.55 | 320 | £142–£182 | Moderate aggressive ground (AC-3), exposed slabs |
| C30/37 | RC30 | 37 N/mm² | 30 N/mm² | 0.55 | 300 | £145–£185 | Exposed RC elements, car parks (XD1/XD2), XF3 |
| C32/40 | RC32 / FND4 | 40 N/mm² | 32 N/mm² | 0.50 | 340 | £155–£200 | AC-4 ground, car parks (XD3/XF4), marine XS3 |
| C35/45 ★ | RC35 | 45 N/mm² | 35 N/mm² | 0.45 | 360 | £160–£215 | High-rise columns, PT slabs, bridge decks, precast, piles |
| C40/50 | RC40 | 50 N/mm² | 40 N/mm² | 0.40 | 380 | £175–£230 | High-rise, marine severe, post-tensioned specialist |
| C45/55 | RC45 | 55 N/mm² | 45 N/mm² | 0.35 | 400 | £195–£260 | Very high strength precast, long-span bridge beams |
| C50/60+ | Special / HSC | 60+ N/mm² | 50+ N/mm² | ≤0.30 | 420+ | £220–£320+ | Ultra-high strength — specialist precast / research |
★ C35/45 / RC35 is the focus of this page. All prices are indicative May 2026 UK trade account ready-mix estimates. Specialist exposure class mixes (marine, aggressive ground) typically add £10–£25/m³. Confirm current pricing with your local supplier.
| Constituent | In-Situ Structural (RC35) | Precast / PT (RC35) | Notes |
|---|---|---|---|
| Cement / binder | 360–380 kg (CEM III or CEM II) | 370–400 kg (CEM I 52.5N) | CEM III/GGBS for durability; CEM I 52.5N for rapid early strength in precast |
| Free water | 140–158 litres | 130–150 litres | Lower water in precast — higher binder gives more strength |
| Fine aggregate (sharp sand) | 580–650 kg | 560–630 kg | Zone 2–3 BS EN 12620. Cleaner aggregate reduces admixture demand. |
| Coarse aggregate | 1,020–1,110 kg (20mm) | 980–1,070 kg (14mm or 10mm) | Smaller NMS preferred in precast for surface finish quality |
| Superplasticiser (PCE-based HRWR) | 3.5–6.5 litres | 4.0–8.0 litres | Essential at w/c ≤ 0.45. Polycarboxylate ether (PCE) standard in 2026. |
| Air-entraining admixture | 0–0.25 litres | Rarely used | Required for XF3/XF4 freeze-thaw + de-icing exposure. Target 4–6% air. |
| Retarder | 0–2.5 litres | Not typically used | For large in-situ pours, hot weather, or long transport times. |
| Water-cement ratio (w/c) | ≤ 0.45 | ≤ 0.40 | Tightest of the standard ready-mix grades. Never add water on site. |
| Fresh density | ~2,400–2,440 kg/m³ | ~2,410–2,450 kg/m³ | ~2.42 tonnes/m³ for structural dead load calculations. |
| 28-day cube strength (characteristic) | ≥ 45 N/mm² | ≥ 45 N/mm² | Mean strength typically 52–60 N/mm² to achieve characteristic with margin. |
| 7-day cube strength (indicative) | ~33–36 N/mm² (CEM III) | ~38–44 N/mm² (CEM I 52.5N) | Higher with CEM I 52.5N — enables earlier stressing in PT construction. |
C35/45 achieves a characteristic cube strength of 45 N/mm² at 28 days — 80% stronger than GEN3 / C20/25 (25 N/mm²) and 12.5% stronger than C32/40 (40 N/mm²). The cylinder strength of 35 N/mm² is used directly in Eurocode 2 structural design.
In the BS 8500 designated mix system, C35/45 is ordered as RC35 from UK ready-mix suppliers. Always specify RC35 when ordering — not just "C35" — to ensure the correct minimum cement content, maximum w/c ratio, and aggregate specification are used.
Standard RC35 / C35/45 ready-mix costs £160–£215/m³ in 2026. London prices reach £200–£245/m³. The North East of England offers the lowest prices at approximately £158–£192/m³. Always obtain at least two supplier quotes before ordering.
The maximum water-cement ratio for C35/45 is 0.45 — the tightest of the standard in-situ grades. Superplasticiser (PCE-based HRWR) is essential in every C35/45 mix. Never add water on site under any circumstances — even 5 litres extra per m³ can cause 28-day cube test failures.
C35/45 requires at least 360 kg/m³ of cement or binder — 50% more than GEN3's 240 kg/m³. For specialist exposure applications with blended cements, total binder content may reach 380–420 kg/m³, significantly increasing production cost per m³.
C35/45 is the standard minimum concrete grade for post-tensioned slabs and flat slabs in UK commercial construction. The high compressive strength handles tendon anchorage bearing stresses and the low w/c provides excellent chloride resistance to protect the PT tendons.
C35/45 concrete must be supplied from a QSRMC or BSI-assessed batching plant with full third-party quality audit, constituent material traceability, and regular plant cube testing. Always request a Declaration of Performance (DoP) or conformity certificate with every delivery.
Site cube testing per BS EN 12350-1 is mandatory for virtually all C35/45 structural pours. Minimum one set of 6 cubes per 50m³ or per day's pour — 3 at 7 days, 3 at 28 days. For PT construction, early-age testing (3–4 days) confirms minimum stressing strength.
Fresh C35/45 concrete weighs approximately 2,400–2,440 kg/m³ (~2.42 t/m³). A 6m³ transit mixer carries ~14.5 tonnes of concrete — total truck GVW approximately 27–31 tonnes. Always verify site access road and any culvert or bridge capacity before the truck arrives.
The low w/c and high superplasticiser content of C35/45 — typically delivered at S3–S4 slump — requires pump placement for virtually all structural pours. Book a boom pump (£450–£1,400/day) or line pump (£400–£700/day) in advance. Pump prime slurry must not enter the structural pour.
RC35 with CEM I 52.5N reaches approximately 80–82% of 28-day cube strength at 7 days. With CEM III (high-GGBS) blends, 7-day strength is 60–70% of 28-day — important for formwork striking decisions on large structural elements.
C35/45 must be cured for a minimum of 7 days — typically with curing compound applied immediately after finishing, or polythene sheeting sealed at edges. In wind or temperatures above 25°C, mist-spraying the surface before curing compound application prevents rapid evaporation and premature drying.
C35/45 is a high-strength structural concrete with a characteristic compressive cube strength of 45 N/mm² at 28 days, designated RC35 under the BS 8500 named mix system. It is specified in the UK for structurally demanding applications including: columns in multi-storey buildings where small cross-sections must carry large loads; post-tensioned slabs and flat slabs in commercial and residential construction; transfer beams and transfer structures; bridge decks and highway infrastructure; bored and driven concrete piles; precast structural elements including pretensioned beams and bridge units; and marine structures requiring very long service life and maximum chloride resistance. It is not a domestic or general-purpose grade — its specification should always be confirmed by a structural engineer.
In May 2026, C35/45 / RC35 ready-mix concrete costs approximately £160–£215 per m³ delivered by transit mixer across most of England, with the Midlands close to the national average of approximately £165–£205/m³. London and the South East are at the top of the range at £200–£245/m³. The North East of England is the most competitive at approximately £158–£192/m³. Mini-mix delivery costs £225–£300/m³; volumetric on-site mixing costs £188–£240/m³. Always obtain at least two local quotes — prices vary by 20–28% across the UK and specialist exposure-class mixes add a further £10–£22/m³.
C35/45 has a characteristic cube strength of 45 N/mm² versus 40 N/mm² for C32/40 — a 12.5% increase in strength. The maximum water-cement ratio is 0.45 for C35/45 versus 0.50 for C32/40, and the minimum cement content is 360 kg/m³ versus 340 kg/m³. The structural significance is that C35/45 allows structural engineers to design more slender columns, thinner slabs, and longer spans for the same structural loading. In practice, C32/40 covers the most demanding standard exposure classes (XD3, XF4, XS3) — C35/45 is typically chosen for structural strength reasons rather than purely durability reasons, though its lower w/c also provides somewhat better durability than C32/40 in the same exposure class. In 2026, C35/45 typically costs £5–£20/m³ more than C32/40 depending on region and supplier.
C35/45 costs more than lower grades for several compounding reasons: the minimum cement content is 360 kg/m³ versus 300–340 kg/m³ for C30/37 and C32/40 — more cement is the largest single cost driver; the maximum w/c of 0.45 demands a higher dose of high-performance superplasticiser (PCE-based HRWR) at approximately £2–£4/litre; the more rigorous plant quality control and QSRMC third-party auditing adds overhead to production costs; and the tighter conformity requirements mean more plant cube testing and greater administrative burden per m³ produced. Combined, these factors add approximately £15–£30/m³ over C30/37 pricing. The structural benefits — smaller column sections, thinner slabs, longer spans — typically justify this premium on projects where space efficiency drives commercial value.
For most structural in-situ C35/45 pours placed by pump, specify S3 slump (100–150mm) as a minimum, or S4 (160mm+) for heavily reinforced sections where concrete must flow around congested bars without vibration assistance. At the maximum w/c of 0.45, C35/45 without superplasticiser would have an S0 or S1 slump — far too stiff for structural concrete placement. The required workability is achieved entirely through the superplasticiser, not by adding water. For self-compacting concrete (SCC) versions of C35/45 used in complex precast molds or congested reinforcement, the slump-flow target is typically 600–750mm measured by the flow table method per BS EN 12350-8.
The volume of concrete required for any element is calculated as: length (m) × width (m) × depth (m) = volume (m³). For cylinders (piles, columns), use: π/4 × diameter² × length. Add 10% wastage for in-situ structural pours — a cold joint in a C35/45 column or beam is a serious structural defect requiring engineering assessment and potentially costly remediation. Use the calculator at the top of this page for standard rectangular pours. For complex shapes, break the element into simple rectangles and sum the volumes. Always round up to the nearest 0.5m³. For large pours over multiple truck loads, ensure you have continuous supply booked — stopping a C35/45 structural pour creates a cold joint that may require the structural engineer's written acceptance.
Yes — conformity cube testing per BS EN 12350-1 is a mandatory quality requirement for all C35/45 structural pours and is normally specified by the structural engineer as a project quality requirement from the outset. Take a minimum of one set of six cubes per 50m³ of concrete placed, or per continuous pour — testing three cubes at 7 days and three at 28 days at an accredited testing laboratory. For post-tensioned construction, additional cubes tested at 3 or 4 days are required to verify the minimum stressing strength before tendon jacking begins. Retain all delivery tickets, cube test reports, and conformity certificates in a permanent quality file for the project — these documents may be required by the building owner, mortgagee, or future purchaser for the full design service life of the structure.
Technically yes — C35/45 is structurally and durability-wise more than adequate for any domestic application. However, it is significantly over-specified and over-priced for domestic use. A standard domestic garage floor or driveway requires only GEN3 / C20/25 (25 N/mm²) — using C35/45 adds approximately £60–£80 per m³ in concrete cost without any practical benefit for domestic vehicle loading and foot traffic. The lower workability of C35/45 at low w/c also makes surface finishing more demanding for non-specialist contractors. Reserve C35/45 for the structural applications it is designed for — columns, PT slabs, piles, bridge decks — and use GEN3 or C25/30 for domestic floors.
Under standard UK curing conditions (15–20°C), C35/45 with CEM I 52.5N cement reaches approximately 80–85% of its 28-day cube strength at 7 days. With CEM III blended cement (high GGBS), 7-day strength is typically 62–72% of 28-day. For post-tensioned construction, the minimum stressing strength (typically 25–35 N/mm² cube) is usually reached at 3–5 days with CEM I 52.5N. Full 28-day characteristic strength is achieved at 28 days — but the concrete continues to strengthen beyond 28 days, reaching 110–130% of 28-day strength at 90 days, particularly with blended cements containing GGBS. This long-term strength gain is beneficial for structural capacity but should not be relied upon in design without specific assessment.
Minimum reinforcement cover for C35/45 depends on the exposure class and design service life, as specified by the structural engineer per Eurocode 2 (BS EN 1992-1-1) and BS 8500-1. Typical minimum values for common applications: XC3 / XC4 (moderate / high humidity external) — 35–40mm; XD2 / XD3 (chloride from de-icing, wet-dry) — 45–55mm; XS2 / XS3 (marine, submerged / tidal zones) — 50–75mm depending on 50-year or 100-year design life; bridge decks per DMRB — typically 50–75mm. These minimum values include the allowance for construction tolerance and the concrete quality factor — they must be achieved consistently using calibrated spacers at the spacings specified in the structural engineer's drawings. Cover measurement surveys are standard QA practice on major structural concrete projects.
C40/50 has a characteristic cube strength of 50 N/mm² versus 45 N/mm² for C35/45 — an 11% increase in strength. The maximum w/c drops from 0.45 to 0.40, and the minimum cement content rises from 360 to 380 kg/m³. In structural design, C40/50 allows further reduction in column cross-sections and slab depths where C35/45 is already at its limit, and it is used for the most demanding marine and chloride-exposure applications requiring a 100-year design life. In 2026, C40/50 costs approximately £175–£230/m³ — a premium of approximately £15–£25/m³ over C35/45 that is justified when the structural or durability analysis requires the additional strength or impermeability. C40/50 is also the standard grade for many precast bridge beams in the UK where long spans and prestress levels push concrete stress limits beyond what C35/45 can accommodate.
C35/45 / RC35 ready-mix concrete is supplied by all major UK concrete producers including Hanson, Aggregate Industries, Tarmac, and CEMEX from QSRMC-certified batching plants across the UK. Not all plants stock C35/45 as a standard product — contact your preferred supplier in advance to confirm availability, the specific cement blend they use, and to request historical conformity test data. For specialist blended cement mixes (marine, high sulfate), additional lead time of 2–5 working days may be required while the specialist cement is sourced. For small volumes, volumetric concrete suppliers can mix C35/45 on site but confirm the mix design meets RC35 specification before accepting delivery.
Additional Resources 2026: Ready-mix at Hanson Concrete | Tarmac Ready Mix | CEMEX UK | Standards at BSI Group | Technical guidance at The Concrete Centre | Structural engineers at IStructE | Building control at LABC | Infrastructure at CIHT
© 2026 C35/45 Concrete Price per Cubic Metre UK. All prices are indicative May 2026 estimates. Concrete specification must be confirmed by a structural engineer. Always request a QSRMC conformity certificate from your ready-mix supplier for structural C35/45 pours.