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 – 1889 Hull, Quebec
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 • 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) C Calcium Concrete S Silicate Strength H Hydrate Happens
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.
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.
Outdoor Sulfate Test Type V Cement W/C-ratio = 0.65 Type V Cement W/C-ratio = 0.39
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.
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.
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 Blended Hydraulic CementsASTM C 595 & AASHTO M-240
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
4 main parts of Cement mill test report Plant and Production Info Chemical Data Physical Data General Info
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 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