Book Description

This paper reports on the state of the art, from the standpoint of state agencies, of the use of statistical quality assurance procedures for the acceptance of bituminous concrete production and construction. Information on the procedures being used by the 50 state highway agencies, as of the spring of 1978, was obtained through a questionnaire and is reported. The paper deals with two areas involving bituminous concrete: (1) production, which primarily encompasses determining the asphalt content and gradation of the aggregate; and (2) construction, which comprises the roughness, thickness, and density of the pavement. The responses to the questionnaires showed that 25 agencies have a statistical quality assurance specification for accepting production, although three of these agencies stated that the program was still experimental. For construction, 25 states, coincidently, also reported employing a statistical quality assurance program. Most of these have a specification dealing with density. The estimated annual dollar savings were reported to be fromUSD100 000 toUSD1 000 000. For those agencies not now using quality assurance specifications, the specifications of most interest were those for production and for the density and roughness of the pavement. Eleven agencies indicated that they are not now using nor are they contemplating the use of statistical quality assurance specifications.