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The reinforced concrete housing for the linear electron accelerator had unusually severe requirements for dimensional stability. These special requirements resulted in a "tailored" structural concrete specification with particular emphasis placed on temperature control, shrinkage, and quality. Included is a brief description of the preliminary concrete investigations and the concrete specification highlights. The construction methods, quality control, properties of the concrete, recent dimensional changes in the structure, cracking, and epoxy injection are discussed. [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]

A kinetic study of the reaction between calcium chloride and portland cement was made. It was found that: (1) Although calcium chloride reacts with C3A1 the reaction rate, particularly in the presence of gypsum, is too slow to account for the set acceleration; (2) CaCl2 definitely accel-erates strength development in hydrating C3S but does not react chemically with the C3S; (3) Electron micrographic evidence suggests that CaCl2 alters the shape of the hydration products formed when cement sets. [ABSTRACT FROM AUTHOR]