ACI 225R-19 Guide to the Selection and Use of Hydraulic Cements

ACI 225R-19 Guide to the Selection and Use of Hydraulic Cements. 3.2.1 Masonry cements—These are used in masonry mortars. They are specifed in ASTM C91/C91M and their use is covered by ASTM C270 and ACI 530/530.1. Plastic and mortar cements are also used in mortars and specifed in ASTM C1328/C1328M and ASTM C1329/C1329M, respectively. In Canada, masonry and mortar cements are specifed in CSA A3002. 3.2.2 Special colored cements—Certain portland cements can give the fnished product special colors, such as white or buf, which are used for architectural purposes. White and buf cements are usually furnished to meet ASTM C150/ C150M specifcations. 3.2.3 Modifed portland cements—Modifed portland cements as described in ASTM C90, which are sometimes referred to as block cements, are manufactured to meet the needs of the concrete masonry unit manufacturing industry. 3.2.4 Expansive or shrinkage-compensating cements— These are designed to expand a small amount during the frst few days of hydration to ofset the efects of later drying shrinkage. Their purpose is to reduce cracking resulting from volume decrease due to shrinkage or to cause stressing of reinforcing steel (ACI 223R). Those manufactured in the U.S. depend on the formation of a higher-than-usual amount of ettringite during hydration of the cement to cause the expansion (ASTM C845/C845M). The expansive ingredient, an anhydrous calcium sulfoaluminate, can be purchased separately. Magnesium or calcium oxide can also be used as expansive agents. 3.2.5 Rapid-hardening hydraulic cements—These are designed to give rapid strength gain during the frst 24 hours of hydration. Four categories of performance are specifed in ASTM C1600/C1600M with strength requirements from 1.5 to 24 hours. Rapid-hardening hydraulic cements can be used in the same application as portland and blended cements, and usually include processing or functional additions. They are typically used for repair applications or where very rapid strength gain is needed. 3.2.6 Regulated-set cements—Regulated-set cements are similar in composition to portland cements, except that the clinker from which they are made contains a small quantity of fuorine. They are formulated to have unusually short setting times followed by development of a moderate early strength. 3.2.7 Well cements—Well cements are manufactured specifcally for use in sealing spaces between well casings and linings, and the surrounding geological formations. They are usually required to comply with API 10A. These cements specifed in API 10A can also meet ASTM speci- fcations—for example, Class G well cements meeting API 10A often meet...