Dopravní stavby - Fakulta stavební - Vysoké učení technické v Brně

12812th International Scientific Conference, April 20-22, 2009 Brno, Czech Republicparabola was used with ordinates Y = (d/D) 0,5 *100 (%). The Fuller parabola represents asphalt mixtureswith the densest embedding of aggregate particles. The asphalt mixtures with the designation “I” had thesieve curve above the Fuller parabola at the upper sieve curve range limit; the asphalt mixturesdesignated as “II” had the sieve curve identical with the Fuller parabola; the asphalt mixture designatedas “III” was the typically designed mixture below the Fuller parabola; and, finally, the mixturedesignated as “IV” was designed at the lower limit of the sieve curve range.As the void content is regarded in the Czech mixture design method as the most importantparameter, there were demands to design the mixtures within the void content for:- AC 11 surf in the narrowed interval 3,5 – 4% (according to the CSN 73 6121 = 3 – 5%,ČSN ČSN EN 13108-1 = 2,5 – 4%)- AC 16 bin in the narrowed interval 4 – 5% (according to the CSN 73 6121 = 4 – 7%,ČSN EN 13108-1 = 4 – 6%)The designed asphalt mixtures were compacted with 2x75 blows of the Marshall hammer, whichare prescribed by the Czech standard for heavy traffic pavements. After the optimalization of the bindercontent according to the above mentioned criteria, additionally asphalt mixtures with optimum contentminus 0,5 % were also compacted. The aim of this lowering was the simulation of the in praxis allowedscattering of the dosing at the mixing plant. With regard to the use of these types of asphalt mixtures forheavy traffic with high intensities and respecting the continental climate conditions in the CzechRepublic, the basic non-modified binder 50/70 both for wearing and binder course asphalt mixtures wasused.Figure 1: Sieve curves I, II, III, IV AC 11 surf and sieve curve rangeDesignation of the Binder content ρ bssd ρ max V VMA VFAmixture % kg.m -3 kg.m -3 % % %I AC 11 surfII AC 11 surfIII AC 11 surfIV AC 11 surfoptimum - 0,5% 4,1 2375 2507 5,3 14,8 64optimum 4,6 2394 2489 3,8 14,6 74optimum - 0,5% 4,0 2376 2507 5,2 14,5 64optimum 4,5 2402 2490 3,5 14,1 75optimum - 0,5% 5,1 2353 2471 4,8 16,6 71optimum 5,6 2369 2454 3,5 16,5 79optimum - 0,5% 5,7 2326 2464 5,6 18,6 70optimum 6,2 2343 2438 3,9 18,1 79ČSN 73 6121 - - - 3-5 - -CSN EN 13108-1 - - - 2,5-4 - (75-83)Table 1: Evaluation of mix design for AC 11 surf