Composite Cement Testing Dyckerhoff Germany

1. Composite CementTesting Dyckerhoff Germany Denver, June 2012, Heiko Plack

2. Test Programme • Combinationstested (varyingcontents): Cementitiouscomponent: • API Class G (medium coarsecement, Blaine 3.100 cm2/g) • API Class G + CEM I 42,5 N (medium finecement, Blaine 3.900 cm2/g) • API Class H (coarsecement , Blaine 2.550 cm2/g) Additive: • Silicaflour • Medium fine (Blaine 3.200 cm2/g) • Coarse (Blaine 1.000 cm2/g) • Natural pozzolan (veryfine, Blaine 8.000 cm2/g) • Variationsinclude also changingwater-to-cement/blendratio = slurrydensity • Blendsweretestedaccordingtophysical API Spec 10A requirements

3. Components Involved (Characterization)

4. DiscussionOfResults • Assumption (Dyckerhoff proposal): Standardizationeffortstarget on specifying a „basic“ cement, and not a „specialcement“, e.g. lightweightcement (coveredby Lafarge NA proposal) • = slurrydensityforperformancetestingis > 1.800 g/cm3 • Additives do affecttheslurrydensityby • theirown absolute densitydifferingfrom Portland cement • higherspecificsurfaceareaincreasingthewaterdemand • = difficulttospecifythewater-to-cement/blendratio, likeforcurrentbasiccements, G and H • However, mostimportantperformancerequirementsidentifiedas • Free fluid (slurrystability) • Max. consistency 15 – 30‘ („rheology“) • Thickening time Schedule 5 („pumping time“) • Compressivestrength 8h@140°F („later“ strength)

5. DiscussionOfResults – Conclusion (I) • Blendsof different cementcomponents (reactivity / fineness) + silicaflourof different finenesshavebeentested (+ a veryfinenaturalpozzolan) • Apart fromthecontentofusedcomponentsthewater-to-cement/blendratiohasbeenvariedrespectivelyadjusted. • Itis evident that a cementmanufacturerhassufficientdegreeoffreedomtoadjustphysicalperformancepropertiesof a compositecementbyvarying • Cement type (reactivity) • Additive finenessandcontent • Water-to-cement/blendratio

6. DiscussionOfResults – Conclusion (II) • Thus • nomaximumormininimshareof additive istobespecified, • nowater-to-cementratioistobespecified, • instead, a slurrydensityrangeistobespecifiedforperformancetesting

7. Conclusion / Suggestion (I) - Lafarge NA proposal Suggestion tospecifytwonew API Spec 10A Composite CementClasseswiththefollowingphysicalrequirements: • Composite cement#1 (API Class E?) → Lafarge NA results / proposal: • Additives: Pozzolanic (natural + artificial), listofmaterialstobedefined! • Slurrydensityforperformancetesting: 12,0 lb/gal< SG < 16,7 lb/gal • Free fluid: < 5,9% • API Schedule 5 thickening time: TT > 90‘ • Max. consistency 15 – 30‘: < 30 Bc • Compressivestrength24h@100°F: > 500 psi NochemicalrequirementstobespecifiedforbothnewClasses!

8. Conclusion / Suggestions (II) – Dyckerhoff proposal • Composite cement#2 (API Class F?) → Dyckerhoff results / proposal • Consideredas a „basiccement“ • Additives: Silicaflour + Pozzolans • Slurrydensityforperformancetesting: 15,0 lb/gal< SG < 16,7 lb/gal • Free fluid: < 5,9% • API Schedule 5 thickening time: 90‘ < TT < 120‘ (130‘?) • Compressivestrength 8h@140°F: > 1.000 psi Nochemicalrequirementstobespecified ! However, classificationas HSR grade possibleif • Portland clinkerusedcomplieswith HSR requirementsofClasses G/H

9. Conclusion / Suggestions(III) • Specifyingslurrydensityrequires a referenceto API RP 10B forthetestmethod. Mudbalancesusuallyavailableat all cementmanufacturer‘slabs, calculationfrom absolute densitiesofcomponentsmay also beconsidered. • Requirementtoprovidetestreportalongwithanyordershallstate: • Slurrydensityatwhichperformancetestswereconducted • Water-to-cement/blendratioatwhichperformancetestswereconducted • Share of Portland cementrespectivelyof additive • Type of additive (silicaflour, fly ash, naturalpozzolan) • + resultsofphysicaltestingasspecified (seeabove) • Chemical specification ???

10. Test Results