In cold asphalt with hard base-bitumen the water breaks out from the bitumen and the binder in the mass solidifies at different rates depending on the containing stone material in the asphalt. If the break occurs before laying the mass becomes unworkable. The intention by this examination is control this process by the mass extraction process should take place when energy is supplied into the mass through a vibrator famine. From previous tests the hypothesis is that the rock flour controls the breaking-process and the workability. Today, the problem is that the mass curing process starts too early and it becomes difficult to manage and work with and the results of the paving are bad. The thesis project also examines coverage and stiffness module, it’s performed on the NCC's road laboratory in Umeå 4/4 - 15/4 in 2016.
Six stone materials from different quarries with different properties are tested. Fraction 0-16 mm from each rock quarry are handmixed, two asphalt samples produced by two different mixing- and assessment-methods. Coverage, workability and the breaking-process are assessed and recorded in a matrix.
Next, replaced ordinary rock flour (0-2 mm) with rock flour from a quarry of a previously known good stone material. With the remaining makadam (2-16 mm) the process are made all over again and the results are analyzed and compared.
An asphalt with rock flour from quarry Supartallen and the remaining makadam from quarry Stöningsberget shows improved results compared with fraction 0-16 mm from quarry Stöningsberget and further tests in laboratory are made with this mixture. These quarries are geographically fairly close to each other, 250 km (about 150 miles), which motivates to choose these quarries for a full scale-test in the future. From these mixtures asphalt-bodies are manufactured by gasket with gyratory compactor and stiffness module is examined.
In the economic and environmental profit attempts are made with a residue from the steel industry. An attempt carried out with the slag from ladles (0-2 mm). The slag is mixed with stone material from quarry Supartallen where workability, breaking process and coverage is investigated. This is an initial attempt to introduce how the asphalt mixture behaves mixed with the slag.
An evaluation was made with matrix where each asphalt mixture included. The asphalt mixture is graded according to machinability, coverage and breaking control. The bowl was analyzed and conclusions about the break could be drawn. Analyzes of the curing process and coverage was made by dismemberment of the mass. The results indicate that the rock flour has a significant role in coverage, extraction at mixing and mining process, however, the stiffness module has the same results in all mixtures. The mere stone flour shouldn’t be the problem but still has a significant role. At the aggregate of Supartallen is so good for the consideration and use of stone materials with similar properties and not rock material with a high amount of SiO2 as it provides poor coverage. The mass harden too quickly may depend on the content of binder, further laboratory work should be done with the binder content in focus.