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Concretes made with water-reducing retarders showed improved freezethaw durability, primarily as a result of increased strength. Specimens made from constant slump, constant cement factor mixtures containing several agents at various dosage levels had higher flexural and compressive strengths than the control specimens. Flexural strengths at 7 and 28 days correlated significantly with durability factor. Microscopic studies indicated that there were minor differences between the air void systems of control and test concretes. In particular, spacing factors increased with retardation. This appeared to result from air entrainment by the water-reducing retarders and from bubble dissolution. [ABSTRACT FROM AUTHOR]

This third report of ACI Committee 212, Admixtures for Concrete, updates the previous reports of 1944 and 1954. In this report admixtures are classified in 15 groups according to type of materials constituting the admixtures, or to the characteristic effects of their use. Where an admixture possesses properties identifiable with more than one group it is discussed with the group that describes its most important effect on concrete. Types of admixtures discussed are: (1) accelerating; (2) water-reducing and set-controlling; (3) grouting; (4) air-entraining; (5) air-detraining; (6) gas-forming; (7) expansion-producing; (8) finely divided mineral; (9) damp-proofing and permeability-reducing; (10) bonding; (11) alkali-aggregate-expansion-reducing; (12) corrosion-inhibiting; (13) fungicidal, germicidal, and insecticidal; (14) flocculating; and (15) coloring. An extensive list of references is included. [ABSTRACT FROM AUTHOR]

These specifications are a reference standard which the engineer or archi-tect may make applicable to any building project by citing them in the project specifications. Individual chapters or sections cannot be copied into project specifications since their meanings will be changed by taking them out of context. The specifications must be supplemented by designating or specifying individual project requirements. Four lists are provided listing places in these specifications and items that will require, or may require, specific treatment by the specification writer. The list of items requiring designation or specification are classed as: mandatory; additional mandatory, items designated or specified if the subject matter applies to the project; re-quirements at variance with these provisions; and requirements which are purely optional. [ABSTRACT FROM AUTHOR]

Recommendations for producing good interior and exterior portland cement plastering are described. Subjects covered are: important factors involved, materials, proportioning and mixing, sampling and testing, methods of application, bases, crack control, application and curing, and decorative finishes. [ABSTRACT FROM AUTHOR]

Recommendations are given on the applicability of shotcrete to different types of construction, material requirements, and application procedures. Equipment requirements are given for both the dry mix and wet mix processes. The testing of shotcrete is covered in some detail. The necessity for a well-qualified application crew is stressed. [ABSTRACT FROM AUTHOR]

These specifications are a reference standard which the engineer or architect may make applicable to any building project by citing them in the project specifications. Individual chapters or sections should not be copied into project specifications since their meanings will be changed by taking them out of context. The specifications need to be supplemented by designating or specifying individual project requirements. Four lists are provided listing places in these specifications and items that will require, or may require, specific treatment by the specification writer. The list of items requiring designation or specification are classed as: mandatory; additional mandatory, items designated or specified if the subject matter applies to the project; requirements at variance with these provisions; and requirements which are purely optional. [ABSTRACT FROM AUTHOR]

The general requirements for producing satisfactory concrete during cold weather are discussed, as are methods for achieving these requirements. It Is emphasized that for many structural concretes, protection considerably in excess of that required to insure freedom from damage by early freezing is required to assure safe development of strength. Accelerators, keeping of temperature records, heating of materials, subgrade preparation, protective insulating coverings, heated enclosures, curing, and form removal are discussed. Supplementary material on the effect of curing temperatures on concrete strength is referenced in authoritative sources. A list of selected references is included. [ABSTRACT FROM AUTHOR]

Set retarded concrete placed in a bridge deck and finished with conventional equipment exhibited a severe surface deterioration in the form of flaking several days after paving. Similar concrete placed in the approach slab on a granular subgrade did not flake. Laboratory and field investigations showed that the flaking was due to the formation of a weak plane immediately below the surface of the concrete and was closely connected with the bleeding characteristics of the mix. The solution was found in reducing the bleeding rate of the concrete by a change in the type of set retarding admixture. [ABSTRACT FROM AUTHOR]

These specifications are a reference standard which the engineer or architect may make applicable to any building project by citing them in the project specifications. Individual chapters or sections should not be copied into project specifications since their meanings will be changed by taking them out of context. The specifications need to be supplemented by designating or specifying individual project requirements. Four lists are provided listing places in these specifications and items that will require, or may require, specific treatment by the specification writer. The list of items requiring designation or specification are classed as: mandatory; additional mandatory, items designated or specified if the subject matter applies to the project; requirements at variance with these provisions; and requirements which are purely optional. [ABSTRACT FROM AUTHOR]

The general requirements for producing satisfactory concrete during cold weather are discussed, as are methods for achieving these require-ments. It is emphasized that for many structural concretes, protection con-siderably In excess of that required to insure freedom from damage by early freezing is required to assure safe development of strength. Accelerators, keeping of temperature records, heating of materials, subgrade preparation, protective insulating coverings, heated enclosures, curing, and form removal are discussed. Supplementary material on the effect of curing temperatures on concrete strength is referenced in authoritative sources. A list of selected references is included. [ABSTRACT FROM AUTHOR]