Blended cements are a type of hydraulic cement similar to portland cement. Blended hydraulic cements are produced by blending and inter-grinding two or more types of fine materials: portland cement and one (or two) of the following: limestone, slag, or pozzolans like fly ash, silica fume, or other natural pozzolan such as calcined clay. These blended materials are typically referred to as Supplementary Cementitious Material (SCM). Finely ground limestone used in a blended cement can replace up to 15% of portland cement clinker thereby reducing GHG potential by an additional 10% over ordinary Portland cement.
Blended hydraulic cements must conform to the requirements of ASTM C595 (or AASHTO M 240), Standard Specification for Blended Hydraulic Cements. Blended cements can be used in all aspects of concrete construction in the same manner as portland cements. Blended cements can be used as the sole cementitious material in concrete, such as C150 cements, or they can be used in combination with other supplementary cementitious materials and strategies added at the concrete plant.
ASTM C595 recognizes four classes of blended cements:
- Type IL, Portland-limestone cement
- Type IP, Portland-pozzolan cement
- Type IS, Portland blast-furnace slag cement
- Type IT, Ternary blended cement
Blended cements can be tested to verify special properties like moderate or high sulfate resistance, and low or moderate heat development.
In June of 2020, CalPortland introduced a new line of environmentally friendly ASTM C595 blended cements under the brand of ADVANCEMENTTM. These blended cements provide maximum GHG reduction by reducing clinker content of portland cement with a blend of either limestone, natural pozzolan, or other approved SCM.
For more information please click to visit the ADVANCEMENTTM website