アスファルトコンクリートにおける粗骨材の最大粒径に関する一実験

抄録

It is the main purpose of this study to ascertain whether or not the maximum size of coarse aggregate will affect the stability of asphaltic concrete and the optimum percentage of its coarse aggregate.
In this study, crushed stone, natural river sand and limestone powder were used for aggregate. The maximum sizes of crushed stone were 25, 20, 13 and 10mm. The percentages of coarse aggregate (>2.5mm) were 65, 60, 55, 50, and 45. The asphalt content varied from 5.5% to 9.5%. The properties of asphalt mixtures were evaluated by the Marshall test.
The main conclusions to be drawn from the date obtained are as follows:
(1) The maximum size between 13 and 25mm had negligible effect on the Marshall stability, whereas considerable reduction in stability was obtained when 10mm size was used. Therefore, 13mm size can be used for dense-graded asphaltic concrete.
(2) The maximum size between 10 and 25mm had little effect on the optimum percentage of coarse aggregate. Consequently, it is not necessary to change the ratio of fine aggregate to coarse aggregate, when 13mm size is used instead of 20mm size.
(3) The authors regard the specific limit of Japan Road Association for gradation of overall aggregate of dense-graded asphaltic concrete as appropriate.