8/12/2023 0 Comments Road base mixed with cement![]() ![]() ![]() 70%, and after water conditioning (ITS wet) the increase was 250%, significantly improving the water sensitivity (TSR). It was shown that the addition of 2% of Portland cement to the mixture improved its indirect tensile strength in dry conditions (ITS dry) by approx. An amount of RAP equal to 20% was used in research by Niazi and Jalili for assessing the effect of Portland cement and hydrated lime on the properties of a mineral-binder mixture with foamed asphalt. These percentages typically obtain high levels of mechanical performance and resistance to moisture. The most commonly used amount of reclaimed asphalt is in the range of 20–70% depending on the specific construction, climatic or operating conditions of the rehabilitated pavements, enabling the reuse (recycling) of a large amount of other used building materials. It should be borne in mind that the layout of the existing construction layers determines the percentage share of individual components in the mixture of the recycled base course. Materials obtained from the above-mentioned layers come in the form of reclaimed asphalt pavement (RAP), reclaimed cement concrete (RCC) and reclaimed aggregates (RA) from unbound mixtures, which all can be used in the composition of a recycled road base layer. Most of the roads reconstructed with this technology are pavements with flexible or semi-rigid structures and the processed structural layers may, in addition to asphalt layers, include improved subgrade, cement concrete and unbound mixtures. The main purpose of using deep cold recycling technology is to maximize the use of the material obtained from the old worn-out layers of the road surface. Recycling techniques are now widely used in road construction and they most prominently include producing top asphalt pavement courses with reclaimed asphalt pavement (RAP) and deep cold recycling techniques, enabling road bases to be produced using recycled materials in high quantities, as well as other underlying structural materials. Use of Recycled Materials in Pavement’s Upper Structural Layers The small effects of the incorporation of reclaimed cement concrete were attributed to the time passed typically between the demolition and new pavement construction and to the presence of a second binding material-bitumen.ġ.1. The obtained differences between the mixtures were not found to be statistically significant. The mixtures containing reclaimed cement concrete were characterized by increased uniaxial compressive strengths after each curing period (3, 4, 7, 14 and 28 days)-by 11.5 kPa on average and e.g., 498 kPa vs. The tests were performed using two mixtures, i.e., a reference mixture and a mixture containing 25% reclaimed cement concrete. Because reclaimed cement concrete, unlike natural aggregates, is expected to have a residue of the non-hydrated cement covering the aggregate grains, which may result in a secondary cementation process after its application in a road base, this avenue was explored by tracking the time evolution of the compressive strength of the final material. The paper presents the results of exploratory research on the use of reclaimed cement concrete in cold-recycled mixes with foamed bitumen. ![]()
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