This article presents the results of fatigue testing and assessment of the mechanical and physical properties of the concrete pavement of the A6 motorway, which was put in service in 1938. After 82 years of operation under heavy traffic loading conditions, the pavement was fully recycled by crushing of the existing concrete and reuse of the reclaimed material in the new courses of pavement placed as part of the motorway renewal project. The main objective of this research was to determine the properties of the tested concrete, including compressive strength, water absorption and freeze-thaw resistance after 150 cycles of alternate freezing and thawing. The resistance of the concrete to the action of de-icing products was also checked. The article also presents the results of petrographic analysis of the aggregates. Additionally, concrete sampled from the pavement was evaluated for freeze-thaw resistance in relation to the determined porosity characteristics. The tested concrete, which was subjected to over 80 years of traffic loading on the A6 motorway, was found to meet the highest requirements as currently applied for the extra heavy-duty pavements. With a compressive strength value in excess of 50 MPa, the tested concrete can be rated at least CC40, according to EN 13877-2:2013-08. The samples were found to satisfy the freeze-thaw resistance requirements of an F150 rating. The air void analysis showed that the analyzed concrete contained 1.6% of micropores, i.e., air voids smaller than 300 μm (A300). The spacing factor, in turn, was below 0.200 mm (L = 0.185 mm). The example of the A6 motorway renewal project served to demonstrate that reclaimed concrete aggregate, obtained by crushing the entire pavement, can be used for production of the new pavement courses.
By recycling used glass containers, we are able to recover and reuse their valuable properties, which is a way to preserve the relevant natural resources and lessen environmental burdens. For example, recycled waste glass (in the form of powder) can be used in the production of concrete. This article analyses the effect of waste glass addition on the properties of C12/15, which is used, for example, as concrete bedding material to support road drainage gutters and kerbs. Ground waste glass was used as a filler in the mix, i.e., without decreasing the amount of cement. Brown glass collected as municipal solid waste was used in this research. The research comprised an experiment prepared on the basis of the central composite design. The independent variables included water/cement ratio and the amount of glass powder, expressed as the glass to cement ratio by weight. The adopted research program mainly included the definition of the concrete compressive strength, water absorption and freeze–thaw resistance after 25 and 100 cycles of freezing and thawing. For selected systems, the characteristics of air voids in hardened concrete were also defined. The beneficial effect of ground waste glass added as a filler to the concrete mixture on the strength and durability of concrete was confirmed by the obtained test results.
This article presents the results of research on the possibility of replacing fly ash with recycled waste glass in lower-strength concrete mixes. The results of testing concrete mixes containing either waste-glass powder or fly ash are presented in the article. A standard C12/15 concrete mix was chosen for the tests based on its common use for producing concrete for footings to support road kerbs and gutters along national roads in the Polish province of West Pomerania. In the first step of the testing procedure, reference mixes were prepared with 22.5% and 45% fly ash in relation to the content of cement. In the next step, mixes were prepared based on the same specification, except that glass powder was added in place of fly ash. The samples were then tested to determine the influence of waste-glass powder on the main properties of the prepared concrete mixes and on the performance of the concrete when hardened. All the samples were tested for 7 and 28-day compressive strength, water absorption, and freeze-thaw resistance in water. Next, the performance parameters of the samples containing waste-glass powder were compared to the reference mixes containing an equal amount of fly ash. The test results and their analysis allow us to conclude that mixes containing glass powder are not only equal to mixes containing fly ash, but even outperform them by a wide margin in terms of durability.
The environmental considerations need to be taken into account in any road resurfacing and upgrading project, for example, by reusing asphalt rubble for production of new pavement courses. Mixtures containing larger amounts of recycled asphalt pavement are improved by adding rejuvenator additives. The tests performed on the recycled asphalt mixtures containing lard imidazoline confirm the suitability of this agent for paving applications. Lard imidazoline was found to improve the stiffness modulus, fatigue performance and resistance to the action of water and freezing temperatures. The parameters obtained at the optimum content of additive complied with the criteria defined for virgin asphalt concrete and other mixtures of that kind.
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