New Cement Specification and Cement Types Road Pavements Forum Thursday 17 May 2001

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New Cement Specification and Cement TypesRoad
Pavements Forum Thursday 17 May 2001
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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

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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

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SABS adopts new cement standards in 1996

• SABS ENV 197-1 covering Common Cements
• SABS ENV 413-1 covering Masonry Cements

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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

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Nomenclature (cont.)

• Extender type
• S - Blastfurnace slag
• D - Silica fume
• V or W - Fly ash
• L - Limestone
• M - Composite

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Nomenclature (cont.)

• Strength grade

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Nomenclature (cont.)

• Example CEM II B-W 42,5
• Portland fly ash cement
• Containing 21 to 35 fly ash
• 2-day-strength gt 10 MPa
• 28-day-strength gt 42,5 and lt 62,5 MPa

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Average 28-day compressive strength of OPC/CEM I
42,5
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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.)

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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

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Thank you all for your attendance