This method outlines procedures for obtaining samples of mate-rials processed for use as concrete aggregate or of raw materials being investigated for such use, and selecting material for testing from the samples so obtained. Procedures applicable to a number of typical situations with respect to the nature occurrence, and condition of materials, and with respect to the purposes for which the samples are to be taken are described.

This specification covers chemical agents proposed for use as surface-applied retarders to prolong the period of time during which air-water cutting is effective as a means for cleaning construction joints in concrete or to delay hardening of mortar in surfaces of concrete intended to have an exposed-aggregate finish.