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Copyright of Beton- Und Stahlbetonbau is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Here a possible alternative joint design in plain concrete pavements was investigated. The basis for this is to cover the concrete pavement with a thin jointless carbon reinforced concrete layer (CRC layer) of 50 to 70 mm as the top concrete. In the process, the classic joints already present in the lower concrete layer are also covered. The carbon reinforcement with a very high load capacity is intended to generate a finely distributed crack pattern in the upper concrete layer, thus preventing the penetration of moisture and other fluids into the joint area. This method thus represents an alternative to conventional joint sealing. Such a construction method is applicable both in the context of repair and new construction measures. In addition to tests on the cracking behaviour of CRC for concrete pavements, the main focus was on tests on large scale composite beams (classic jointed lower concrete + CRC layer). The focus was on the effects of static and cyclic bending on the material behaviour of the CRC over the moving joints in the lower concrete and the bond behaviour of lower and carbon reinforced concrete. The influence of differently designed bond breakers on the crack formation in the joint area was also considered.

Copyright of Beton- Und Stahlbetonbau is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Kurzfassung: In Sonderfällen des Betonbaus wird ein Materialverhalten angestrebt, das sich durch ein hohes plastisches Stauchvermögen auszeichnet. Zwar liegen bereits erste Ansätze für solche Betone vor, abgesicherte Kenntnisse zum Stauchverhalten sowie zu den maßgeblichen Einflussgrößen sind aufgrund fehlender experimenteller Studien jedoch bisher äußerst begrenzt. Der vorliegende Beitrag beschreibt experimentelle Untersuchungen zum Stauchverhalten stark porosierter Betone. Das Ziel war es, das Stauchverhalten grundlegend zu charakterisieren und relevante material‐ sowie versuchstechnische Einflussparameter zu identifizieren und zu quantifizieren. Die Porosierung der Betone erfolgte durch die Verwendung von Blähglas und Schaumstoffperlen in Kombination mit einem Schaumbildner. Durch die Variation des Wasserzementwertes wurde auch der Einfluss der Matrixfestigkeit berücksichtigt. Das Stauchverhalten wurde in einaxialen Druckversuchen unter Voll‐ und Teilflächenbelastung untersucht. Des Weiteren wurden die Stauchversuche sowohl mit als auch ohne Umschnürung durchgeführt, um den Einfluss der Querdehnungsbehinderung zu ermitteln. Die wesentlichen Untersuchungsergebnisse werden anhand der ermittelten Spannungs‐Verformungskurven sowie der erfassten Struktur‐ und Gefügeänderungen von gestauchten Proben dargelegt. [ABSTRACT FROM AUTHOR]

Deck caps of bridges—in Germany shortly known as "bridge caps"—are usually made of steel reinforced concrete to form the anchoring area for the guardrail of bridge deck edges on existing cantilever slabs. Combined with protective devices, the outside arranged deck caps provide safety against lateral breaking or crashes of vehicles. Due to their exposed position in the cross section of bridges and the particularly intensive stresses, the deck caps are considered as wear parts and have to be renewed several times during the service life of a bridge. The decisive factor here is the discrepancy between the frost resistance of the concrete and the crack width restriction. On the one hand, only very small cracks (<0.2 mm) can be accepted to prevent corrosion of the rebars under the strong exposure of these elements. To confine crack widths without applying an excessively high degree of reinforcement, a low concrete compressive strength is advantageous. On the other hand, a sufficient frost resistance requires a correspondingly high compressive strength. With carbon reinforcement, these contrary points could be defused and simultaneously the needed durability could be provided. Therefore, slightly modified deck cap concretes combined with a carbon reinforcement mesh were tested to examine the bond behavior with and without freeze–thaw attack. To prove the characteristics of this combined system, the crack formation and crack distribution were investigated experimentally. The test results were compared to calculated values from a mathematically tool to be able to develop different reinforcement concepts in future that can ensure an optimized crack formation and crack width for deck caps. [ABSTRACT FROM AUTHOR]