This book describes procedures and methodologies used predominantly to obtain a diagnosis of damaged concrete possibly caused by Alkali-Aggregate Reaction (AAR). It has two primary objectives, namely firstly to identify the presence of AAR reaction, and whether or not the reaction is the primary or contributory cause of damage in the concrete; and secondly, to establish its intensity (severity) in various members of a structure. It includes aspects such as field inspection of the structure, sampling, petrographic examination of core samples, and supplementary tests and analyses on cores, such as mechanical tests and chemical analysis. Evaluation of test data for prognosis, consequences and appraisal will be more fully set out in AAR-6.2.

In the 1910's and 20's, economic pressures and the rise of the motorbus produced dramatic changes in the streetcar industry. A promising solution to ensure profitability was the introduction of the so-called "Safety Car" designed by Stone and Webster Corp. engineer Charles O. Birney. This type of small trolley featured several innovations, including "deadman" controls that automatically cut power to the motors and applied brakes in an emergency. The main attraction for transit companies however was the fact that the cars' design allowed a man to both run the car and take fares. The elimination of the conductor without any apparent compromise in safety sold the public on the cars and produced an immediate cost savings. This high quality booklet is a reprint of two brochures originally produced by Westinghouse Electric and Manufacturing Co. and General Electric to promote these efficient streetcars.