Type I/II (MH): Moderate Heat of Hydration (and Moderate Sulfate Resistance)
Type I/II (MH) Portland Cement is uniquely formulated to provide: 1) the basic performance characteristics of Type I Portland Cement, 2) the moderate sulfate resistance and lower heat of hydration characteristic of Type II Portland Cement, and 3) the slower heat generation of Moderate Heat (MH) Portland Cement by limiting the heat index to a maximum of 100. (The heat index is the sum of C3S + 4.75 C3A). Using MH cements will reduce temperature rise, peak temperature and, minimize temperature related cracking, which is especially important when concrete is placed in warm weather. Type II (MH) can often be used in structures of considerable mass, such as large piers, large foundations, and thick retaining walls, as well as common Type I projects, such as roads, bridges, reinforced concrete buildings, tanks, reservoirs, culverts, water pipe, sidewalks, and masonry units. Suwannee American Cement Company Type I/II (MH) Portland Cement exceeds all applicable ASTM, Federal, State highway and AASHTO specifications for Portland Cement, and can be shipped by bulk or packaged.
Type IL: Portland-Limestone Cement
Type IL Portland Cement is uniquely formulated to reduce the environmental footprint of Portland Cement. This cement is manufactured by intergrinding portland cement clinker with up to 15% limestone. Blended cements such as Type IL are 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 or they can be used in combination with other supplementary cementitious materials added at the concrete plant. Laboratory tests indicate that the performance of concrete made with Type IL cement as a group is similar to that of Type I/II (MH) cement concrete.
Source: Portland Cement Association