Abstract: During production of asphaltic concrete mixtures, the mix controls of a mixing plant are periodically adjusted to proportion fine aggregate, coarse aggregate, and asphalt cement in accordance with a new Riguez Index test thereby to produce pavement materials which when compacted contains a predetermined, controlled and substantially constant volume of air voids and/or percent voids filled (film thickness). The Riguez Index test is a volumetric analysis method which can quickly, i.e., within an hour, be performed in that it mathematically correlates the variations in the physical properties of the aggregated with the desired voidage to be attained in the compacted mixture. Under the test, both mix design and proportioning at the plant site are performed over a single sieve size, the No. 4 sieve being preferred.

Abstract: A uniform asphalt pavement of substantial area composed of aggregates of varying natural qualities produced by a systematic process including mix design, mix analysis, and plant control methods. A volumetric comparison is mathematically made between blendings of coarse and fine aggregates defined over a single sieve size and a Riguez Index to determine voidage in the compacted aggregate mixture. The Riguez Index is characteristic to the particular fine aggregates used in the blending. For controlling voidage at the mixing plant, the respective quantities of coarse and fine aggregates injected into the mixing plant is controlled over the same single sieve size used for demarcating coarse and fine aggregates in mathematically computing the volumetric comparison. Further, a stability function derived from different combinations of crushed fine and blend sand, and a flexibility function derived from different mix quantities of asphalt cement provide control of flexibility and stability values.

Abstract: An improvement to a laydown machine comprising an unsegregator shroud connected to the ejector chute of the aggregate elevator transporter. The shroud extends around the chute to constrain the path of aggregates as they are fed into the feed box of the paving machine.

Abstract: A mix design method for determining the gradation of coarse and fine aggregates to be combined to achieve a predetermined percentage of air void volume and voids in mineral aggregates for a given quantity of asphalt cement. The method uses a volumetric value known as the Riguez Index which is derived from a compacted representative sample of fine aggregates to be used in the mixing plant. Volumes of graded aggregate composites are calculated at various gradation values below the bulking point and compared with the Riguez Index thereby providing the basis for graphically selecting a particular gradation wherein an aggregate mixture of said particular gradation contains, when compacted, the desired predetermined void volumes. Coarse aggregates and fine aggregates are demarcated by the No. 4 screen.