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New Cement Specification and Cement Types Road Pavements Forum Thursday 17 May 2001. Historical product range in South Africa. OPC - SABS 471 RHC - SABS 471 PBFC - SABS 636 PC15 (SL or FA) - SABS 831 PFAC - SABS 1466 Masonry cements - no standard. Cement extenders.
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New Cement Specification and Cement TypesRoad Pavements Forum Thursday 17 May 2001
Historical product range in South Africa • OPC - SABS 471 • RHC - SABS 471 • PBFC - SABS 636 • PC15 (SL or FA) - SABS 831 • PFAC - SABS 1466 • Masonry cements - no standard
Cement extenders • SABS 1491 covers the quality of extenders for use at the mixer • Slags from Iscor at Pretoria, Newcastle and Vanderbijlpark were confirmed suitable through research • Fly ashes from Matla and Lethabo were also shown to meet requirements in extensive test programmes
SABS adopts new cement standards in 1996 • SABS ENV 197-1 covering “Common Cements” • SABS ENV 413-1 covering “Masonry Cements”
Nomenclature • CEM I, II, III, IV and V • I - Portland cement • II - Portland ……… cement • III - Blastfurnace cement • IV - Pozzolanic cement • V - Composite cement • A, B or C • indicates level of extender e.g. in CEM II A is 6-20% and B is 21-35%
Nomenclature (cont.) • Extender type • S - Blastfurnace slag • D - Silica fume • V or W - Fly ash • L - Limestone • M - Composite
Nomenclature (cont.) • Strength grade
Nomenclature (cont.) • Example CEM II B-W 42,5 • Portland fly ash cement • Containing 21 to 35% fly ash • 2-day-strength > 10 MPa • 28-day-strength > 42,5 and < 62,5 MPa
Factors to be considered when selecting cement type • Cost of concrete • 28-day compressive strength • Early compressive strength development • Ability to resist aggressive environment • Sensitivity to poor site practices and extent of supervision • Other properties (colour, heat development, control of ASR, etc.)
Cautionary remarks • Do not extrapolate performance data for one cement as representing all cements • Do not assume that what is permitted in Europe will automatically work in SA • Ask for details of product performance from the manufacturer - check uniformity and performance relative to the issues of importance • Do not think that a SABS mark indicates that the cement is fit for any application