ACI 212.3R-16 Report on Chemical Admixtures for Concrete

ACI 212.3R-16 Report on Chemical Admixtures for Concrete. 4.2—Use of chemical admixtures in sustainable construction The use of chemical admixtures can benefcially infu- ence the environmental impact of concrete construction in a number of areas. These include, but are not limited to: a) During concrete production: i. Reduce the amount of natural resources used in the manufacture of concrete or concrete products by: 1. Reducing the amount of potable batch water used through the use of normal-, mid-, and high-range water reducers (Chapter 6) 2. Reducing the amount of cementitious material used (Chapter 6) 3. Reusing fresh stabilized concrete or concrete wash water through the use of extended set-control admixtures (Chapter 9) 4. Reducing the duration time and temperature required to heat/steam cure precast/prestressed concrete (Chapters 6, 7, and 20) ii. Reduce or eliminate process-water-treated discharge though application of extended set-control admixtures during truck washout, enabling the gray water thus produced to be used in concrete production (Chapter 9) b) During construction: i. Reduce the initial emissions footprint and embodied energy of concrete materials either by: 1. Reducing the amount of cement needed, or allowing alternative cementitious materials with lower environmental signature, while maintaining the same or improved concrete properties (Chapters 6 and 20) 2. Reducing the actual volume of concrete needed through application of admixtures to achieve higher strength, with beneft both in cementitious materials and aggregate volumes; this requires alternate structural design (Chapter 20) 5.2—Materials for air entrainment Many materials can function as air-entraining admixtures. Those materials, however, that are used to create cellular concrete by creating gas bubbles inside the concrete are not acceptable air-entraining admixtures (ACI 523.1R). Examples of these materials include hydrogen peroxide and powdered aluminum. 5.2.1 Water-soluble compounds—Water-soluble, air- entraining admixtures are formulated using salts of wood resins, synthetic detergents, salts of petroleum acids, salts of proteinaceous acids, fatty and resinous acids and their salts, and organic salts of sulfonated hydrocarbons. Not every material that fts the preceding description, however, will produce a desirable air-void system. All air-entraining admixtures should meet the requirements of ASTM C260/ C260M. Most commercial air-entraining admixtures are in liquid form, although a few are powders, fakes, or semi- solids. The proprietary name and the net quantity in pounds (kilograms) or gallons (liters) should be indicated on the containers in which the admixture is delivered.ACI 212.3R pdf download.