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The alkali reactivity of siliceous aggregates depends on the microstructural disorder of the aggregate, plus further factors that can increase the phenomenon. The use of infrared (IR) spectroscopy to quantify this disorder is suggested. A simple graphic elaboration of an IR spectrum allows one to determine a disorder coefficient Cd. This allows one to compare rapidly and with assurance the different degrees of disorder for a number of siliceous minerals. Using as reference some samples whose alkali reactivity has been determined in a different way, a Cd limit value has been fixed. For this Cd value, the disorder is such as to raise no doubt about the aggregate susceptibility to alkali-silica reaction. This method can also be applied to calcareous aggregates that include siliceous minerals; if these inclusions are more than 10 percent, it is possible to use the sample without exclusion of the calcareous matrix phase.

Alkali-aggregate reaction is essentially a reaction between the hydroxyl ions in the pore solution of a mortar or concrete and the siliceous (or other alkali-susceptible) minerals in the aggregate. Study of the pore solution chemistry of mature cement pastes, mortars, and concretes has been possible in recent years through the development of pore solution expression techniques. This paper reviews the progress that has been made in explaining the phenomena associated with alkali-aggregate reactions in terms of pore solution composition. In particular, consideration is given to the effects of alkali level and water content of the concrete on the severity of reaction, the role of alkalis in pulverized fuel ashes, granulated blast furnace slags, and other cement replacement materials in determining their effectiveness in preventing damage and the contribution to pore solution alkalinity made by salt contamination of aggregates and deicing salts.

Design methods for buried pipe are fairly well established, but durability is not normally given proper consideration. Durability of a pipe is a consideration as significant as its hydraulic and structural functions. The definition of a durable concrete pipe contains three variables that must be evaluated: the required performance, the properties of precast concrete pipe, and the service conditions. This paper discusses these variables and presents guidelines on how they can be evaluated and on current countermeasures for anticipated aggressive environments.

Concrete structures in the northern regions of Japan have a higher risk of deterioration due to freezing and thawing because of the cold climate and heavy snows. The resistance of concrete to freezing and thawing is studied actively in the laboratory in Japan, but there is still much to be studied about the deterioration of concrete structures exposed in the field. A survey of the deterioration of concrete used in road bridges was made in Iwate Prefecture, a district in northeastern Japan where there are many different climatic conditions. Over 300 bridges were examined. The majority of bridges observed were damaged to some degree by freezing and thawing. The degree of deterioration differed in different parts of the bridges. Although the main cause of deterioration is presumed to be poor construction, it can be pointed out that the lack of consideration for design of these structures adds significantly to their deterioration. The degree of deterioration also depends on regional climatic conditions. In this report, the relation between the degree of observed deterioration and the climatic conditions is discussed.

The design of a durable concrete mixture and the control of that mixture during construction commonly involves the measurement of properties relating directly to structural attributes, strength, or modulus of elasticity. Of these, compressive strength, along with cement, water, and air content, are most easily measured, and variations in these properties can be related to variations in durability. A personal computer using spreadsheet software and/or an HP-41C program provides a quick means to: (a) evaluate a proposed mixture; (b) establish laboratory trial batch proportions; (c) determine if the trial batch balances; (d) provide adjustments for subsequent trial batches; and (e) evaluate the variations in the production of concrete based upon the compressive strength. A normal-weight concrete mixture that balances provides reasonable assurance that properties and proportions are correct for evaluating durability attributes of mixtures. Data-base management and graphics features of the spreadsheet programs may be used to help evaluate variations in strength during construction, which may be indicative of variations of durability attributes.