Portland Cement

Joe Diedrich

Technical Services Manager

Beginning of the Industry

• Portland cement was first patented in 1824

• Named after the natural limestone quarried on the Isle of Portland in the English Channel

Portland cement first production dates in the US and Canada.

• North America - 1871 Coplay, Pennsylvania

• Canada – 1889Hull, Quebec

Manufacturing of cement starts at the quarry

Stone is first reduced to 5-inch size, then to 3/4 inch, and stored

Dry process of raw mix preparation

Raw mix changes chemically into clinker

Clinker Gypsum

Clinker is ground with gypsum into portland cement & shipped

Cement recipe

• Limestone – CaO

• Sand – SiO2

• Clay and/or Shale – Al2O3

• Iron Ore or Mill Scale – Fe2O3

• Gypsum

ASTM

C 150

Major Phases of Cement Components

Alite = impure tricalcium silicate (C3S) 50%

Belite = impure dicalcium silicate (C2S) 25%

Aluminate = tricalcium aluminate (C3A) 8%

Ferrite = tetracalcium aluminoferrite (C4AF) 12%

Hydration of the cement compounds

Compound Reaction Rate

Strength Contribution

Heat Contribution

C3S Moderate High Early High

C2S Slow High Later Low

C3A Fast Low Very High

C4AF Moderate Low Moderate

Portland cement hydration

Hydration

• Hydration definition:– The formation of a compound by the combining of

water with some other substance; in concrete, the chemical reaction between hydraulic cement and water

The primary product of the reaction between cement and water:

Calcium Silicate Hydrate (C-S-H gel)

Concrete

Strength

Happens

Calcium

Silicate

Hydrate

Calcium Hydroxide

• A secondary product of the reaction between cement and water.

• Calcium hydroxide is not a binder. It is a water soluble compound that takes up space and serves no useful purpose. Calcium hydroxide can contribute to problems such as sulfate attack

Types of AASHTO M85 and ASTM C150 portland cement

• Type I normal, general-purpose cement• Type IA normal, air-entraining• Type II (MS) moderate sulfate resistance• Type II MH moderate sulfate resistance and

moderate heat of hydration• Type III high early strength

(Typically Type I ground 50% finer)• Type IV low heat of hydration

(very uncommon)• Type V high sulfate resistance

What is the difference between Type I and Type II?

• Type I has no C3A limit, however, a Type II is limited to a maximum of 8% C3A• There is no such thing as a Type I/II cement.• This is slang terminology for a product that meets criteria for both Types.

Type II & Type V Sulfate Resistant

Cements

What’s the difference between a Type II and a Type V?

• Type V has different limitations on the aluminum and iron.• One of the main differences is a lower maximum C3A.• Type V has a maximum limitation on the combination of the iron

and aluminum compounds.

Performance of Concretes with Different W/C-Ratios in Sulfate Soil

Outdoor Sulfate TestType V CementW/C-ratio = 0.65

Type V CementW/C-ratio = 0.39

Type II Moderate Heat Cements

What’s the difference between a Type II and a Type II MH?

Type II MH has a restriction on the combination of C3S and C3A which are related to heat generation.

What’s the difference between a Type II and a Type II MH?

Type II MH has a maximum Blaine of 4300, however if the C3S 4.75(C3A) ≤ 90, this Blaine restriction does not apply.

Type II MH has a lower 3 day and 7 day minimum strength that apply when the optional heat of hydration requirement is specified.

Type IIIHigh Early Strength Cements

What is different about a Type III?

• Type III cements have a higher SO3 maximum limit because of their fineness.• Type III cements also have a higher maximum C3A limit.

White Portland Cement

Blended Hydraulic Cements ASTM C 595 & AASHTO M-240

• Type IS(X) Portland blast-furnace slag cement• can include between 0% and 95% ground granulated blast

furnace slag, encompassing old Types IS, I(SM), and S

• Type IP(X) Portland pozzolan cement• can include between 0% and 40% pozzolan, encompassing

old Types IP and I(PM)

The letter “X” stands for the nominal percentage of the SCM included in the blended cement

Ternary Blended Cements• New Type IT• 1 slag and 1 pozzolan or 2 pozzolans• Same chemical and physical limits for

ternary blended cements as for binary blended cements (IP or IS) with the same predominant SCM

• Amount and type of SCMs used in nomenclature

2009 Cement Specs Update

Ternary Blended Cements• Nomenclature

Format: Type IT(AX)(BY)

Where A and B are SCM types and X and Y are amounts• S=slag or P=pozzolan

• Primary (highest content) SCM listed first

• If X=Y requirements of Type IT(P>S) apply (Type IP)

• Example: Type IT(S25)(P15) contains 25% slag and 15% pozzolan

2009 Cement Specs Update

Ternary Blended Cements

• Since Type IT(S25)(P15) has more slag than pozzolan, requirements are the same as Type IS(25)

• Type IT can meet MS, HS, or LH options

2009 Cement Specs Update

Understanding a Cement Mill

Test Report

Plant and Production Info

Chemical Data

Physical Data

General Info

4 main parts of Cement mill test

report

Understanding a Cement Mill Test Report

• Cement Identification

• Plant

• Production Date & Silo Information

Cement Mill Test Information

• Chemical and Compound Information

• Specification Limits and Type

Cement Mill Test Physical Data

• Physical Test Data

Cement Mill Test Report – Specification Type Required

• Report Identifies what cement type it will meet

NCDOT Portland Cement Requirements

• NCDOT requires cement information when submittal of Form 312 identifying source and type of cement

• Maintain a current cement mill test report on hand

• Verify before and during the project the cement source based upon what is identified with each Bill of Lading (BOL) which should match Form 312

NCDOT Form 312 FORM 312U

North Carolina Department of Transportation, Division of Highways, Materials and Tests Unit Statement of Concrete Mix Design and Source of Materials

Contract Plant Standard Concrete Producer S&W Ready Mix Concrete, Co.

County New Hanover Plant Location & DOT No.

Castle Hayne RM323

Resident Engr. Contractor Class of Concrete

B Non-Vib Date 3/ 10/ 10

Mix Design No. P17BNV8 Contractor’s Signature Note Mix Design Units (US or Metric)

US

Mix Design Proportions Based on SSD Mass of Aggregates

Material Producer Source Qty. per Cu. Yd.

Cement Type I / I I L.A. Cementos Argos Colclinker, Cartagena Columbia

436 lbs.

Pozzolan Flyash Class F The SEFA Group Georgetown, SC 131 lbs. Fine Aggregate American Materials Co. I vanhoe Pit 1134 lbs. Coarse Aggregate Martin Marietta Aggregates Lemon Springs Quarry 1780 lbs. Other Aggregate lbs. Total Water Ground Well 35 gals. Air Entraining Agent BASF Admixtures Micro Air As Required Retarder BASF Admixtures Pozzolith 200N As Required Water Reducer BASF Admixtures Pozzolith 100XR As Required Superplasticizer Corrosion I nhibitor Other

Cement BOL

NCDOT Requirements & Concerns

• Each BOL must be accompanied by a current cement mill test report

• Producers found non-complying with NCDOT requirement (cement and producer) will be removed from the NCDOT approval list

• Alkali Silica Reactivity (ASR) is a very real issue in North Carolina and the NCDOT is addressing this critical area