Heavyweight Concrete
Uses : producers have supplied this specialty performance ..:
1- hospitals in x-ray protection
2- bridge designers to provide counterweights on lift bridges
3- designers of nuclear power plants
Mixture proportioning:
Procedures outlined in ACI 211.1 should be used for mixture proportioning. Typical proportions for heavyweight concrete are shown in Table 2.
MATERIALS :
Cement
Cements conforming to ASTM C 150, which would be suitable for conventional concrete and produce the required physical properties, are suitable for use in heavyweight concrete.
Aggregate
Thorough examination and evaluation of heavyweight aggregate sources are necessary to obtain material suitable for the type of shielding required.3 These sources are limited, and a material survey should be conducted to determine availability, chemical and physical qualities
Mixing water
Water and ice to be used in heavyweight concrete should conform to the requirements of ACI 301 or ASTM C 94. In addition, water should be clean and free from injurious amounts of oil, acid, alkali, organic matter, or other deleterious substances.
Admixtures
Conventionally placed heavyweight concrete may contain a chemical admixture meeting ASTM C 494 requirements for Type A or D. Type F or G may also be used to improve the placeability and reduce the tendency for segregation.
Control tests
Conventional heavyweight concrete—The quality of the concrete produced should be controlled by an established pro- gram of sampling and testing. This program should conform to the requirements of national standards such as ACI 318 and to the requirements of the construction specifications. Quality control tests of freshly mixed concrete should include tests of density, temperature, slump, and air content made in accor- dance with appropriate ASTM test
1- hospitals in x-ray protection
2- bridge designers to provide counterweights on lift bridges
3- designers of nuclear power plants
Mixture proportioning:
Procedures outlined in ACI 211.1 should be used for mixture proportioning. Typical proportions for heavyweight concrete are shown in Table 2.
MATERIALS :
Cement
Cements conforming to ASTM C 150, which would be suitable for conventional concrete and produce the required physical properties, are suitable for use in heavyweight concrete.
Aggregate
Thorough examination and evaluation of heavyweight aggregate sources are necessary to obtain material suitable for the type of shielding required.3 These sources are limited, and a material survey should be conducted to determine availability, chemical and physical qualities
Mixing water
Water and ice to be used in heavyweight concrete should conform to the requirements of ACI 301 or ASTM C 94. In addition, water should be clean and free from injurious amounts of oil, acid, alkali, organic matter, or other deleterious substances.
Admixtures
Conventionally placed heavyweight concrete may contain a chemical admixture meeting ASTM C 494 requirements for Type A or D. Type F or G may also be used to improve the placeability and reduce the tendency for segregation.
Control tests
Conventional heavyweight concrete—The quality of the concrete produced should be controlled by an established pro- gram of sampling and testing. This program should conform to the requirements of national standards such as ACI 318 and to the requirements of the construction specifications. Quality control tests of freshly mixed concrete should include tests of density, temperature, slump, and air content made in accor- dance with appropriate ASTM test