| 1. |
- Bissonnette, B., et al.
(författare)
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Recommendations for the repair, the lining or the strengthening of concrete slabs or pavements with bonded cement-based material overlays
- 2013
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Ingår i: Materials and Structures. - : Springer. - 1359-5997 .- 1871-6873. ; 46:3, s. 481-494
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Tidskriftsartikel (refereegranskat)abstract
- The recommendations presented in this publication are inspired by the State of the Art Report edited by the RILEM Technical Committee TC 193 RLS Bonded cement-based material overlays for the repair, the lining or the strengthening of slabs and pavements. The objective is to lay out all the practical aspects to be considered in the design of concrete overlay.bonded concrete overlay process, assessment of the existing structure, surface preparation, overlay materials, design methods, construction procedure and quality control/assurance system, and maintenance.
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| 2. |
- Dias Ferreira Da Silva, Nelson, 1978, et al.
(författare)
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Application of LA-ICP-MS for meso-scale chloride profiling in concrete
- 2013
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Ingår i: Materials and Structures/Materiaux et Constructions. - : Springer Science and Business Media LLC. - 1359-5997 .- 1871-6873. ; 46:8, s. 1369-1381
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Tidskriftsartikel (refereegranskat)abstract
- Chloride represents a major risk for reinforced concrete structures because at a certain concentration, it can promote depassivation of the steel bars and initiate corrosion. Therefore it is important to be able to measure the chloride content in concrete. In this paper the application of laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) for the study of chlorides in concrete is proposed. This scanning technique enables quick multi-element profiling, directly at the sample without the need for further preparation, within a range of sub-millimetre (meso-scale) resolution and with low limits of detection. Optimization of the operating conditions was performed in pressed concrete powder pellets. Linearity of the calibration was verified and limits of detection below 0.05 wt% of cement were determined. Chlorine, calcium and iron distributions were studied in cement based materials of increasing heterogeneity (paste, mortar and concrete). This technique is furthermore proposed for the study of the chloride induced corrosion process, by following element distributions along the concrete-steel interface at the time of depassivation.
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| 3. |
- Edwards, Ylva, et al.
(författare)
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Energy saving and environmental friendly wax concept for polymer modified mastic asphalt
- 2010
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Ingår i: Materials and Structures. - : Springer Science and Business Media LLC. - 1359-5997 .- 1871-6873. ; 43, s. 123-131
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Tidskriftsartikel (refereegranskat)abstract
- This paper focuses on the addition of commercial wax as flow improver in polymer modified bitumen intended for use in mastic asphalt pavements under Nordic climatic conditions. Different aspects are dealt with. The aim of the project is to make mastic asphalt used in Sweden today (for bridges, parking decks etc.) more environment friendly and easier to handle. However, wax modification must not have any noticeable negative impact on the performance of mastic asphalt at medium and lower temperatures. The project involves laboratory testing of wax and polymer modified binder mixtures as well as mastic asphalt mixtures. Effects of adding two commercial waxes to one polymer modified bitumen have been studied. The results show that both waxes have a flow improving/viscosity depressant impact on the polymer modified bitumen at higher temperatures, indicating a possible lower laying temperature for the mastic asphalt if modified with such waxes. Moreover, there is a stiffening effect at medium and high temperatures (below placing temperature), indicating a certain positive effect on stability. Concerning low temperature performance, there are results indicating some negative impact on crack susceptibility at low temperatures, more by the addition of one of the waxes than by addition of the other. However, it could be concluded that using up to at least 4% of either wax additive will improve workability for the mastic asphalt product under investigation making it possible to lower working temperatures without seriously affecting its good performance in any negative way.
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| 4. |
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| 5. |
- Garcia, Alvaro, et al.
(författare)
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A parametric study on the influence of steel wool fibers in dense asphalt concrete
- 2014
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Ingår i: Materials and Structures. - : Springer Science and Business Media LLC. - 1359-5997 .- 1871-6873. ; 47:9, s. 1559-1571
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Tidskriftsartikel (refereegranskat)abstract
- Environmental conditions combined with traffic loads contribute to premature deterioration of asphalt concrete pavements, reducing their strength and durability over time. To improve it, fibers can be incorporated in the mixture. Additionally, electrically conductive fibers can be used for self-healing purposes. In this context, this paper evaluates the influence of flexible steel fibers (steel wool) on the mechanical and physical properties of dense asphalt concrete. With these purposes, 25 different mixtures, with the same aggregate gradation and amount of bitumen, but with two different fibers lengths, four different percentages, and four different diameters of steel wool have been considered. Additionally, the influence of fibers on test specimens with three different types of damage: water damage, salt water damage and ageing have been evaluated through particle loss tests. Moreover, the influence of different temperatures on the flexural strength of dense asphalt concrete with steel wool fibers has been studied. It was found that steel wool fibers do not significantly improve the mechanical properties and damage resistance of dense asphalt concrete. On the other hand, steel wool fibers can change the air void distribution of a mixture, and therefore even reduce its particle loss resistance. As a recommendation, it is indicated that, for induction heating purposes, short fibers, with big diameters should be used, since they do not seem to alter the original properties of dense asphalt concrete.
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| 6. |
- Garcia, Alvaro, et al.
(författare)
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Influence of cement content and environmental humidity on asphalt emulsion and cement composites performance
- 2013
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Ingår i: Materials and Structures. - : Springer Science and Business Media LLC. - 1359-5997 .- 1871-6873. ; 46:8, s. 1275-1289
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Tidskriftsartikel (refereegranskat)abstract
- Asphalt and cement concrete are the most popular materials used in the construction of roads, highways, bridge deck surface layers and pavements in airports and other areas with heavy wheel roads. Whereas asphalt possesses, compared to concrete, the advantages of a short curing period, high skid resistance and easy maintenance, it also shows lower fatigue durability, ravelling and rutting due to repeated concentrated loads and susceptibility to temperature changes and moisture. On the other hand, concrete pavements are initially more expensive, have lower driving comfort and are susceptible to cracking due to volume changes and to salt damage. A material with low-environmental impact and with advantages of both asphalt and concrete may be obtained by combining bitumen emulsions and a cementitious material. In this paper, cold asphalt mixtures with different amounts of cement were tested with Marshall stability tests. Selected mixtures were also cured at different environmental relative humidity (35, 70 and 90 % RH). By monitoring the mass of the specimens and estimating the water bound by the cement, the total water remaining in the mixtures was calculated. Details of the microstructure in the mixtures were examined with X-ray microtomography. According to the results of the present study, cement contributes to the hardening of cold asphalt mixtures both by creating cement paste bridges between the aggregates and by removing water from the mixtures through cement hydration. Asphalt and cement composites appear to be promising materials for implementation in real pavements, although their rate of hardening needs to be improved further.
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| 7. |
- Gram, Annika, et al.
(författare)
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Numerical Simulation of Fresh SCC Flow : Applications
- 2011
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Ingår i: Materials and Structures. - : Springer Science and Business Media LLC. - 1359-5997 .- 1871-6873. ; 44:4, s. 805-813
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Tidskriftsartikel (refereegranskat)abstract
- Numerical simulation of self-compacting concrete (SCC) flow shows great potential for developing into a powerful tool for prediction of SCC form filling. Numerical simulation is also of interest for modelling small scale material phenomena. This paper presents three different applications useful for modelling different phenomena on different scales: (i) particles, each representing an aggregate in the concrete, (ii) fluid, modelling concrete as a homogeneous liquid and (iii) particle in fluid, studying details of flow. The methods are compared and evaluated in order to give the reader a quick guidance into the world of possibilities that open up with numerical simulation.
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| 8. |
- Groot, Caspar, et al.
(författare)
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RILEM TC 203-RHM: Repair mortars for historic masonry : Performance requirements for renders and plasters
- 2012
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Ingår i: Materials and Structures. - 1359-5997 .- 1871-6873. ; 45:9, s. 1277–1285-
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Tidskriftsartikel (refereegranskat)abstract
- This article gives a summary of functional_x000D_ and performance requirements for renders and plasters_x000D_ for historic masonry (design, execution and maintenance)._x000D_ Specific attention has been paid to degradation_x000D_ effects, such as caused by salt crystallization and_x000D_ freeze–thaw cycling. Traditional as well as designed_x000D_ prefab mortars are considered for repair intervention.
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| 9. |
- Gudmarsson, Anders, 1983-, et al.
(författare)
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Application of resonant acoustic spectroscopy to asphalt concrete beams for determination of the dynamic modulus
- 2012
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Ingår i: Materials and Structures. - : Springer Netherlands. - 1359-5997 .- 1871-6873. ; 45:12, s. 1903-1913
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, a new application of resonant acoustic spectroscopy (RAS) is examined for constructing asphalt concrete mastercurves from seismic testing. The frequency-dependent material properties can be characterized from multiple modes of vibration through the use of RAS. Beam-shaped asphalt specimens are tested at multiple temperatures to determine the resonance frequencies of the specimens. The resonance frequencies are estimated by applying a small load impulse and measuring the resulting acceleration through the specimens. Using RAS, the material properties of the specimens are determined numerically using the measured resonance frequencies. The results presented show that the frequency-dependent dynamic modulus of the asphalt concrete specimens can be characterized using several modes of vibration at each testing temperature.
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| 10. |
- Harryson, Peter, 1963
(författare)
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Bond between fibre reinforced concrete and fibre reinforced polymers
- 2011
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Ingår i: Materials and Structures/Materiaux et Constructions. - : Springer Science and Business Media LLC. - 1359-5997. ; 44:1, s. 377-389
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Tidskriftsartikel (refereegranskat)abstract
- An experimental study of the bond between ultra-high-performance steel-fibre reinforced concrete (UHPSFRC) cast upon glass-fibre reinforced polymer (GFRP) sheets, as well as of the bond between epoxy-jointed precast UHPSFRC sheets, has been conducted at Chalmers University of Technology. Both shear and tension tests have been performed. Several surface treatments of the different interfaces have been tested. For the joint interface between UHPSFRC and GFRP the best performance was found for a surface with double-bent steel fibres added to epoxy overspread with sand coating, which were allowed to harden prior to casting the concrete. For the epoxy-jointed concrete sheets the best performance was found for a surface where the smooth 'formwork side' was sand-blasted before the epoxy gluing. However, it was concluded that more testing is needed before decisive recommendations can be made. In addition, materials tests of the UHPSFRC have been conducted in both tension and compression.
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