ABSTRACT
Several organisations devoted considerable time and effort, in the 1960’s and 1970’s, to developing rapid methods for compliance purposes. Each method has since been redrafted and is now documented in BSI DD83. A chemical method was developed by scientists at the then Greater London Council (GLC)[6]. A physical method (pressure filtration) was developed at Messrs. Sandberg[7]. A physical separation system, using dense organic liquids, was developed at Laing[8] and in 1974 the Cement and Concrete Association (now BCA) published a report[9] describing arguably the most rapid technique; the ‘constant volume method of the rapid analysis machine (RAM). The RAM, still commercially available, has been subjected to a very detailed laboratory precision experiment[10], a study into delayed analysis by freezing[11] and field investigations[12].
