Cement Replacement Materials: Complete Guide

The cement replacement materials are the materials that replace a share of the Portland clinker in the cement and the concrete without sacrificing the performance of the final product: the fly ash from the power plants, the ground granulated blast furnace slag from the iron works, the silica fume from the ferrosilicon furnaces, the natural pozzolans of the volcanic origin, the calcined clays and the limestone filler: the cement that ships today is very often a blended cement: part clinker and part replacement, and the art of the cement chemist is the art of the proportion: how much replacement is safe, what it does to the strength, the heat, the durability and the price: this document of the package is the guide to the subject: the materials, the chemistry, the dosages, the quality control and the practice of the blended cement.

The Complete Cement Technical Package (931 files including this document, the books, the Excel tools, the courses and the presentations: $249.99 one-time: instant download via the PayPal payment) includes the cement replacement reference with its chapters on the supplementary cementitious materials and the blended cements: this article walks the document: why the cement is replaced, the fly ash, the slag, the silica fume, the pozzolans, the limestone, the blended cement standards, the chemistry of the reactions, the strength and the durability, the concrete practice, the quality control and the environmental accounting: the reader finishes with the working knowledge of the modern cements and the honest numbers behind them.

Why the topic matters more today than ever: the cement industry must cut its carbon while the world builds more: each tonne of the clinker releases about 0.83 tonnes of the CO2, and the fastest available lever is the substitution of the clinker by the materials that react with it: the clinker factor of the blended cement falls from the 95% of the CEM I to the 65–75% of the blends, and with it the emissions, the energy and the cost: the replacement materials also bring genuine engineering benefits: the low heat, the sulfate resistance, the denser microstructure and the longer life of the concrete: the modern cement engineer is above all the engineer of the blend, and this document is the manual of the blend: the chemistry first, the practice last.

1. The Concept of the Cement Replacement: The Clinker and Its Substitutes

The cement replacement is the arithmetic of the modern cement: the cement is the clinker ground with the gypsum, and the replacement is the share of the clinker that is substituted by another reactive or filler material: the fraction is called the replacement level, and its limits run from the few percent of the limestone addition to the 70–80% of the high-slag cements:

• The what: the replacement displaces the clinker, not the gypsum: the gypsum stays in the blend as the setting regulator, and the replacement material takes the place of the cementitious part of the mix: 1 tonne of the CEM I contains about 950 kg of the clinker; the CEM II with the 25% fly ash contains about 700 kg of the clinker and 250 kg of the ash;
• The reactive and the filler: the reactive replacements (the slag, the fly ash, the pozzolans, the silica fume) participate in the hydration; the fillers (the limestone, the fine inert rock) are mostly the passive substances that fill the voids and sometimes react a little: the modern cement uses both: the reactive for the long-term strength, the filler for the packing and the economy;
• The three motives: the economy (the replacement costs less than the clinker per tonne), the environment (each tonne of the removed clinker removes about 0.8–0.9 tonnes from the CO2 chain) and the engineering (the low heat, the durability and the denseness that the blends bring);
• The limits: the replacement levels are capped by the standards and by the concrete practice: the early strength falls with the level of the reactive materials because the pozzolanic reactions are slower than the clinker hydration alone: the high-level blends trade the early strength for the late strength and the durability;

The document presents the concept with a simple rule: the replacement is the investment of the late strength against the early strength, plus the environmental dividend: the engineer who blends the cement is the accountant of a three-strand balance: the cost, the carbon and the calendar of the strength: the whole of the document is the toolbox of that accounting.

2. The Fly Ash: The Fine Pozzolan of the Power Stations

The fly ash is the ash of the coal-fired power plants, captured by the filters from the flue gases: the fine spherical glassy particles built of the silica, the alumina, the iron and the unburned carbon: the fly ash is the most widely used supplementary cementitious material of the industry:

• The classes: the classification follows the calcium content: the low-lime class F ash (the combined silica-alumina-iron typically above 70%) from the anthracite and the bituminous coals is the pozzolanic ash that consumes the lime; the high-lime class C ash from the lignite and the sub-bituminous coals carries enough calcium to be partly self-cementing: the class F is the standard of the cement industry;
• The quality parameters: the loss on ignition (the unburned carbon, typically limited to 4–6% in the standards: the carbon hurts the air entrainment and the admixtures), the fineness (the residue on the 45 micron sieve, typically below 30–35%: the finer the ash, the more reactive), the free lime and the sulfates;
• The reactivity: the ash reacts the pozzolanic way: the calcium hydroxide of the cement plus the silica and the alumina of the ash gives the extra C-S-H and the aluminate hydrates: the glassy spheres react from the surface, slowly, and the blend with the 15–30% ash reaches the reference strength at about the 28–56 days and passes it at the 90 days and beyond;
• The benefits in the mix: the low heat of hydration (the mass concrete of the dams and the foundations), the improved workability (the spherical grains roll and lubricate the mix), the sulfate resistance, the mitigation of the aggregate reaction and the pore refinement of the concrete;

The fly ash is also the question of the supply: the availability follows the power plants, and the carbon content of the ash varies with the furnace operation: the document covers the ash selection, the acceptance and the mixing levels, and treats the ash as what it is in the modern economy: the commercial co-product with the specified quality, not the waste to dump: the ash is counted, tested and blended like any other raw material of the plant.

3. The Ground Granulated Blast Furnace Slag: The Latent Hydraulic of the Iron Works

The slag is the highest-value replacement of the industry: the molten blast furnace slag of the iron making is quenched rapidly in the water or the air into the glassy granules, and the granules are ground to the cement fineness into the ground granulated blast furnace slag (the GGGBS): the slag is not a pozzolan: it is a latent hydraulic material with the cement-like chemistry of its own:

• The latent hydraulicity: the slag glass carries the lime, the silica, the alumina and the magnesia in the proportions broadly similar to the cement: wetted alone, it reacts very slowly; activated by the alkaline environment of the Portland cement (the calcium hydroxide and the alkalis) it hydrates into its own C-S-H: the cement in the blend is the flame that ignites the slag;
• The replacement levels: the 20–35% in the Portland-slag cements, the 35–66% in the blast furnace cements of the CEM III/A-B class, and the 66–80% in the CEM III/C: the higher the slag, the lower the heat, the slower the early strength, the higher the long-term strength and the denser the corrosion-resistant hydrate mass;
• The properties the slag brings: the very low heat of the hydration (the mass concrete), the high sulfate resistance, the resistance to the chloride penetration of the marine structures, the resistance to the alkali-silica reaction and the pale color of the architectural finishes;
• The quality parameters: the glass content of the granules (80% and more: the crystalline slag barely reacts), the fineness of the grind (400–500 m²/kg by the Blaine: finer than the cement), and the activity index measured by the comparative mortar strength against the straight cement: the activity index is the industry’s instrument of the slag quality;

The slag is the highest-volume carbon-free substitute of the clinker: the CEM III cements carry the lowest carbon per tonne of any commercial cement, and at the 90 days their strength exceeds the straight cements: the classic trade of the slag is the time: the concrete that can wait for the strength and needs the durability and the low heat is the concrete of the slag: the marine works, the mass pours, the foundations of the cold climates: the document’s chapters cover the slag proportions, the activators and the curing demands, so that the engineer uses the slag where it pays and keeps the quick ordinary cement where the calendar rules.

4. The Silica Fume: The Densifier of the High Performance

The silica fume is the finest member of the family: the sub-micron spheres of the amorphous silica captured from the smoke of the ferrosilicon and the silicon furnaces: the particles of 0.1–0.5 micron disperse between the cement grains, and the humblest material of the family gives the highest performance per kilogram:

• The pozzolanic peak: the silica surface area per mass is enormous, so the fume consumes the lime of the cement at a fast rate and produces the density of the C-S-H: the high-performance concretes of the 80–150 MPa use the silica fume at 5–10% with the low water and the superplasticizers;
• The packing and the pore: the sub-micron spheres fill the interstices between the cement grains and sever the channels of the concrete permeability: the blended concrete with the fume is the densest and the most impermeable of the family: the material of the underground, the marine and the repair structures;
• The doses and the practice: the typical 5–10% by the mass of the cementitious materials: the fume raises the water demand of the paste and must be balanced with the superplasticizer: the material is sold in the slurry or the densified form, and its handling is the specialist matter (the dust of the fume is the hazard and the care of the silo);
• The alkali sink: the fume binds the alkalis and the lime of the pore water into the C-S-H, mitigating the alkali-silica reaction of the reactive aggregates: the designer of the aggressive environments reaches for the fume when the local aggregates are the doubtful ones;

The silica fume is the specialist tool rather than the bulk replacement: the availability is small and the price is high relative to the cement, so the fume serves the high-performance niche and the repair, while the fly ash and the slag serve the bulk: the document’s chapter explains the doses, the water corrections, the curing conditions and the supply, and it gives the honest verdict: the fume in every pour is the misunderstanding of the economy; the fume where the pore and the alkal subject rules, is the engineering of the best grade.

5. The Natural Pozzolans and the Calcined Clays: The Materials of the Earth

The pozzolans are the oldest cement of the civilization: the Romans built with the volcanic ash of the Mediterranean, and the same family serves the modern industry where the fly ash and the slag are scarce: the natural pozzolans and the calcined clays are the mass of the earth’s own cement:

• The natural pozzolans: the volcanic tuffs, the pumices, the diatomaceous earths and the glassy hydrothermal rocks contain the amorphous silica and the glassy aluminates that react with the lime: the activity depends on the glass content and the fineness: the standards (the EN 197-1 pozzolan definitions and the pozzolanicity tests) govern the acceptance;
• The calcined clays: the kaolinitic clays heated to 600–850°C transform into the metakaolin: the reactive aluminosilicate with the activity approaching the silica fume at the moderate levels: the clay is the most abundant raw material on the earth, and the calcined clay is the candidate of the vast scale;
• The LC3 blend: the limestone calcined clay cement: the clinker (about 40–50%) with the calcined clay (about 30%), the limestone (about 15–20%) and the gypsum: the LC3 delivers the 42.5 class strength with roughly the 40% lower CO2 per tonne than the CEM I: the carbo-aluminate chemistry between the clay, the limestone and the aluminate gives the strength that the sum of the parts would not predict: the LC3 is the most discussed innovation of the decade in the cement research;

The natural materials carry the geography: the quality varies with the source, the composition and the firing, and the document’s acceptance chapters normalize the variability: the activity tests, the fineness and the limits separate the good pozzolan from the sand that only resembles it: the calcined clay, in particular, is the replacement of the abundant: the earth has more clay than it will ever have the iron or the coal, and the cement of the next decades is the cement of the clay.

6. The Limestone and the Fine Fillers: The Cheap Stone That Reacts a Little

The limestone filler is the least celebrated and the most widely used of the replacements: the limestone powder joins the cement at the levels up to about 20% in the standards, and the industry now knows that it is not an inert filler at all:

• The physical role: the filler particles pack between the cement grains, reducing the void space and the water demand of the concrete: the cement with the fine limestone grinds easily (the soft mineral), the concrete flows better and finishes better at the same water:
• The chemical role: the calcite of the limestone reacts with the aluminate phases and the calcium hydroxide to form the calcium carbo-aluminates, and the carbo-aluminates stabilize the ettringite: the limestone plugs the aluminate side that the gypsum alone cannot fully tame: the reaction is modest but real, and the clever coupling with the calcined clay (the LC3) is built on it;
• The standards: the EN 197-1 allows the limestone in the CEM II/A-L (6–20% of the limestone) and the CEM II/B-L classes with the purity limits (the CaCO3 content, the organic carbon limit); the ASTM C595 (the Portland-limestone cement) matches the concept: the limestone cements are the everyday cements of the present industry;
• The trade-offs: the high limestone levels cost the strength (its own reaction is weak), so the best practice couples the limestone with a reactive SCM: the ternary blends of the limestone, the fly ash or the slag and the clinker: two modest replacements often perform better than one large one: the coupling is the modern recipe;

The limestone changes the economics first: it is the cheapest material of the plant, and each tonne of the limestone in the cement is a tonne of the fuel and the calcination avoided: the standards stop the mixture far before the physics ask, and the honest plant publishes the composition on the certificate: the limestone cement is a good cement when the composition is honest and the design respects its character: the document’s chapter covers the proportions and the certificates: the bluff and the treasure are both on the label, and the engineer reads the label.

7. The Blended Cements of the Standards: The Classes of the Composition

The standards made the blended cements the ordered products, and the cement handbook of the package covers the standards in the detail: this document carries the numbers specific to the blends:

• The EN 197-1 classes: the CEM II/A (the clinker 65–79%) and the CEM II/B (the clinker 65–79% of the class with the listed second letter by the material: S for the slag, P for the natural pozzolan, V for the fly ash, D for the silica fume, L and LL for the limestone, M for the mixture): the CEM III (the slag 36–80%), the CEM IV (the pozzolanic) and the CEM V (the composite): each class is a legal recipe with the property limits and the strength classes (32.5, 42.5, 52.5) with the N (normal) and the R (early) suffix;
• The ASTM systems: the C595 (the blended hydraulic cements: the Type IS with the slag, the Type IP with the pozzolan), and the C1157 (the performance cements classified by the properties rather than the ingredients: the literal performance specification of the American practice);
• The local standards: the Portland-pozzolana cement (the IS 1489 in India), the Portland-slag cement (the IS 455), the composite cements of the several codes: each market names its blends and the document maps the names between the systems;

The taxonomy is a contract: the bag that says the CEM II/A-S tells the buyer exactly what he buys: the producer must conform and the consumer must read: the document’s classification tables translate one standard into another, and the reader of the label in the Benelux district can compare the cement of the local plant with the cement ordered of the import: the standards are the language of the trade, and the blended cement lives in that language.

8. The Chemistry of the Reactions: The Pozzolanic and the Latent

Under the various names, the replacement materials reduce to a handful of chemical reactions that the document lays out before the practical chapters:

• The pozzolanic reaction: the calcium hydroxide of the hydrating cement plus the amorphous silica of the pozzolan (the ash, the fume, the natural, the calcined clay) yields the extra C-S-H: the reaction converts the weak lime reserve into the strong binding gel: the classic: the silica plus the calcium hydroxide and the water give the calcium silicate hydrate: the reaction is slow, which is the reason for the strength calendar;
• The latent hydraulicity: the slag is the material with its own lime: the activation by the cementitious environment lets the slag hydrate to its aluminosilicate hydrate products: the slag reaction is simultaneous with the cement reaction, accelerated below the temperatures: black the cement chemistry of the classical phases;
• The carbo-aluminate reactions: the limestone carbonate with the aluminate of the cement and the clay produces the carbo-aluminato hydrates and the stabilization of the ettringite: the reaction explains the surprising gains of the limestone-clay blends and enlarges the cement chemist’s model beyond the classic Bogue phases;
• The pore densification: the sum of the chemistry is the physics of the pore: the hydrates fill more space, the packing is denser, and the transport of the environment (the water, the chloride, the gas) through the concrete falls by the factors of 2–10 in the well-blended concretes: the durability of the blends is the creep and the pore discipline;

One honest paragraph for the chemist’s pocket: the pozzolanic reaction consumes the lime, which is exactly the lime that the carbonation of the hardened concrete also consumes: the blended concrete must be cared for with the curing and the cover: the document’s chemistry chapter covers the balance of the lime and the reserve, so the engineer knows where the strengths live and where the watches live: the chemistry is the map of both.

9. The Strength Development: The Calendar of the Hydrated Blend

The concrete and the cement of the blend are the products of the chemistry and the time, and the document gives the expected strength curves:

• The early strength (2–7 days): the replacement dilutes the fast clinker: at the 20% ash or the 25% slag the strength at the 2–7 days runs at about 70–90% of the straight cement; at the 60–70% slag at 60–80%; the silica fume with the superplasticizer holds the early rate: the early strength is the price of the blend, and the contractors of the fast striping read it with the caution;
• The late strength (28–90 days): the pozzolanic and the latent reaction accelerate far above the reference: the ash catches the parity around the 28–56 days, the slag catches and passes at the 56–90, the fact that at the 28 already exceeds: the late strength of the blend is the income that repays the early deficit;
• The curing: the blends demand the curing more than the straight cement: the pozzolanic reaction needs the moisture for the weeks: the un-cured blended slab is the greatest waste of the blend technology: the document’s tables link the level, the strength class and the required curing duration;
• The mix design: the designers specify the water-cement ratio and the target strength at the 28 days as the standards, and many pick the anti-3 of the 56 or 90 days: the document’s strength tables give the design engineer the data: the w/c, the replacement and the age: the direct path from the class to the mix;

The calendar decides the geometry of the use: the quick-turn products: the low replacement or the fume: the mass pours and the foundations: the slow high-slag: the 90-day contracts: the largest levels: the blend is the payment plan of the strength, and every concrete plant runs on the schedule of the payments: the document’s strength-schedule examples turn the calendar into the concrete decision: the strength curve is read like an offer of the months ahead.

10. The Durability of the Blended Concrete: The Sulfates, the Chlorides, the Alkali

The durability is the strongest argument of the blends: the same pore densification that the chemistry chapter described shows its value in the aggressive environments:

• The sulfate attack: the sulfates of the soil and the groundwater attack the aluminate and the calcium hydroxide of the hardened cement: the slag and the fly ash bind the aluminate and reduce the available lime: the sulfate resistance of the right blend: the blends the standard answer of the sulfate soils;
• The chloride and the reinforcement: the chloride ions of the sea and the de-icing salts reach the reinforcement: the blended concretes (the slag, the ash, the fume) cut the chloride transport by the controlled pore and the binding of the chlorides in the hydrate phases: the marine and the bridgeage structures are the concrete of the blends;
• The alkali-silica reaction (the ASR): the reaction of the alkalis of the cement with the reactive aggregates expands and cracks the concrete: the replacement the alkalis of the cement and the blended C-S-H binds them: the slag and the ash mitigate the ASR and make the reactive aggregate usable under the control;
• The carbonation: the honest warning of the blends: the denser mitigation of the chloride is paid at the atmosphere: the carbonation front of the blended concrete moves, all else equal, a little faster when the reserve of the lime is lower: the reinforcement of the blended concrete needs the full coverage of the cover and the exposure check: the document’s tables give the cover-calculations for each class: the durability of the blends is a design with the measured variables: nothing is free and nothing is lost;

The durability conclusion of the document: the blends are the engineering choice for the specific environments: the sea and the sulfate, the mass and the heat evolution: the aggressive exposures: the blends: the chloride of the first choice: the lime reserve: the carbon: the engineer of the large project carries the document’s exposure tables and selects the class of the ISO environment: the strength of the requested:

11. The quality control of the replacement materials: the acceptance and the consistency

The replacement materials are the industrial products of the varying quality, and the quality control of the SCM is the discipline of the acceptance:

• The fly ash tests: the fineness (the residue on the 45 micron sieve within the 30–40% limit of the class), the loss on ignition (the LOI below the class limit 4–6%), the SO3 and the free lime limits, and the reactivity index against the reference mortar: the EN 450 and the ASTM C618 provide the test and the frequency;
• The slag tests: the glass content (the microscopy of the granulate), the fineness of the grind, and the activity index: the standard requires the minimum strength activity at the 7 days (about 60–75% of the reference) and at the 28 days (about 90–100%): the activity index is the gatekeeper of the slag shipments;
• The natural and the clay tests: the pozzolanicity test (the EN 196-5: the lime consumption of the pozzolan in the fixed environment), the strength activity, the water requirement and the fineness: the calcined clay: the free lime of the raw: the metakaolin reactivity;
• The in-plant blend control: the cement plant meters the SCM into the mill with the weigh feeders (see the materials handling handbook of the package), the product is sampled per shift and the clinker factor of the output is reported: the certificate of the cement states the composition, and the quality system checks the consistency against the declared class;

The quality control of the SCM is the gate of the whole economics: the bad ash and the crystalline slag arrive looking alike, and only the tests open the difference: the document’s acceptance schedules and the frequency of the sampling convert the deliveries into the controlled inputs: the laboratory of the plant is the customs post of the blends, and the checklist of the document is the customs tariff: the unqualified material is turned back at the source: the cheapest insurance of the plant.

12. The Concrete Practice and the High-Performance: The Blend of the Pour

The field chapters of the document connect the cement science to the concrete plant: the proportions that the site actually orders:

• The concrete with the fly ash: the typical concrete mixes with the 15–30% ash replacement: the workability rises, the water can drop slightly, and the key of the practice is the extended slump control and the curing: the transport time of the ash concrete is comfortably long: the trucks of the mass pours profit from the ash;
• The concrete with the slag: the 40–70% slag exposes the concrete of the sea and the earthworks: the mix ratios at the water-cement of 0.35–0.45: the finish is slow and even: the high slag mixes are the masters of the heat control: the designer calculates the adiabatic rise: the slag makes the megastructure without the cold joints;
• The high-performance concrete: the fume class: the 5–10% fume with the superplasticizer: the water-cement ratio below 0.35: the strengths above 80 MPa at the 28, the low the permeability: the track, the pylons, the tunnels and the repair layers: the HPC of the document’s tables covers the proportions, the mixing, the pumping and the humid protection;
• The ternary and the LC3 in the field: the clay-limestone blends reach the concrete plants with the new procedures of the mixing and the spraying: the hydration of the LC3 is slightly slower at the start and the curing and the surface finishing call the attention: the document’s field examples of the LC3 in the precast and the brickwork: the future is already the practice in the several regions;

The practice chapters are the place where the document speaks to the ready-mix engineer: the dosage tables, the correction factors of the water, the initial set times and the curing conditions, the carbon output of each mix: the engineer at the plant of the worksheet replaces the levels and reads the strength, the durability and the cost: the better mix of the day is the output of the sheet: the document’s spreadsheets are among the Excel files of the package, and the art of the replacement is practiced with the numbers every morning fresh for the pour.

13. The Environmental Accounting: The CO2 Saved by the Tonne

The replacement is the environmental instrument of the industry, and the document’s honest north:

• The scale: the Portland clinker at about 0.83–0.9 tonnes of the CO2 per tonne: the cement of the world at 4–4.5 billion tonnes produces about 2.4–2.8 billion tonnes of the CO2 (about 7–8% of the human hand): the clinker reduction by the blending is the immediate lever of that sector;
• The unit economics: the CEM I at about 0.85 unit of the CO2 per tonne of the cement: the CEM II/B at about 0.60: the CEM III/B at about 0.35: the CEM III/C at 0.25: with the full life-cycle impacts of the additions their fuels and transport counted: the comparison of the blends vs the same concrete strength: the carbon output per the class of the concrete is the true measure: the strength-based comparison raises in fact the blends: the smaller cement content per the same strength;
• The carbonation uptake: the hardened concrete absorbs the CO2 of the atmosphere over the decades (the re-carbonation of the hydrates): the blends absorb in the secondary life of the rubble: the balance of the emission and the uptake: the document’s numbers: the honest of the industry: the net of the technical: the chemistry of the process:
• The resources: the fly ash and the slag are the industrial residues that would otherwise landfill: the limestone and the clay are the natural resources: the mining of the clay and the calcination earn their own footprints: the engineering of the carbon: the supply to the local sources: the wheels of the hidden energy:

The environmental accounting of the document is the arithmetic of the modern cement policy: the clinker factor of the national cements is the daily news: the roadmaps: the 50% clinker average: the number that once sounded extreme is now the industry consensus of 2-3 decades: the math: the 50% clinker of the world’s cement saves 400 million tonnes of the CO2 per year vs the current: the blending is the bridge between the today and the CCS of the tomorrow: and the document’s number tables let the reader verify every claim: the honesty is the only salesmanship of the environmental chapter.

14. The Frequently Asked Questions

What is the maximum safe replacement level of the fly ash in the cement?

The standard commercial level is 15 to 35 percent of the ash in the cement: the higher levels (40–60%) exist in the concrete practice with the prolonged curing and the low-heat purposes: the maximum is set by the early strength of the mix: the classical Portland cements suffer no replacement: the acceptance: the standards CEM II/B-V 42.5N at 21–35%: the replacement is safe when the concrete design accounts for the slower chemistry.

The slag cement is weaker in the first week: is that a problem?

Only when the schedule of the construction demands the early loading or the fast stripping: at the 28 days the slag catches and at the 90 it passes the straight cement: the mass and the underground structures rarely care about the first week and benefit enormously from the heat and the durability: the constructor who needs the truck removed at 12 hours should order the type III and the smaller slag, and the constructor of the foundation should not worry: choose the binder for the real age of the structure, not the fiction of the first week.

Does the limestone in the cement make it cheaper and worse?

The well-blended limestone makes the cement cheaper and in the moderate levels (6–20%) it is not worse when the mix and the design follow: the limestone improves the fresh workability, the packing and the flow, and the chemistry argues with the aluminate reactions positively: the cement is always what the certificate says: the buyer who wants the classic CEM I strength pays for the CEM I: the buyer of the PLC pays the honest price per the MPa of its class: the economics: the two tonne of the PLC may be the strength of the two: the spirit of the buyer cover is the same as any time: it is the certificate that tells.

Should I pair the limestone with the fly ash and the slag?

Yes – the ternary blends outperform the single-replacement blends of the same clinker: the limestone feeds the caro-aluminate chemistry, the fly ash and the slag feed the pozzolanic the duration, and the clinker provides the early strength: the ternary is the industrial default of the modern portfolio: the levels of 10–20% limestone + 15–30% of the pozzolan + the remainder clinker are the working recipes of the CEM II and the CEM III/V families.

How do I verify the quality of a shipment of fly ash?

The carbon content (LOI) below the class limit, the fineness on the 45 micron sieve within the class, the consistency of the density, and the mortar activity index of the day in the lab: samplings per the EN 450 or the ASTM C6111: at least one composite per rail and the weekly: the rejects: the shipment must meet the specified: the same acceptance discipline as any raw material: the cement plant laboratory runs the test in a day and the loading decides the day after.

The concretes of the blends last longer in the marine environment: is that known?

Yes, the chloride transport is the unauthorized factor of the marine concrete, and the blends (particularly the slag at 50–70% and the fume combinations) cut the chloride transport by the order of magnitude compared to the CEM I: the reinforced structure of the marine project is designed with the cover and the concrete class: the blended concrete is the standard of the marine practice and the evidence is the hundred years of the ports: the species continue: the document’s the environmental tables of the marine exposure give the concrete the classes to specify.

15. Conclusion

The cement replacement: the modern heart of the cement industry: the fly ash from the stacks of the power plants, the slag of the iron of the steel, the fume of the silicon, the clay of the earth and the limestone of the quarry: the creations that one tonne of the clinker no longer has to bear: the strength sacrificed early and repaid late, the heat calmed, the pores closed, the atmosphere breathed the smaller bill: the discipline of the blend is the discipline of the proportions, and the engineer’s tool is the honesty of the certificate: the document of the package is the manual of that discipline: the materials, the chemistry, the classes, the dosages, the durability and the money: the whole of the cement replacement in the one library.

The Complete Cement Technical Package (931 files: $249.99, one-time, instant download, lifetime access: PayPal) includes this cement replacement document with the whole library: the cement handbook, the concrete references, the quality manuals and the Excel tools: the new cement of the world is the cement of the blends, and the engineer who masters the blends has mastered the technology of the present and the next decades: the knowledge of the package costs less than the value of a single avoided kiln campaign, and its formulas are the formulas of the modern concrete: the click of the purchase is the click of the future: the value of the package is measured in the tonnes of the clinker it will liberate from the furnace and the years of the structure it will protect.

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