Experimental study of tensile response of Strain Hardening UHPFRC at early age

Strain Hardening Ultra High Performance Fibre Reinforced Concrete (SH-UHPFRC), has a high tensile strength (over 10 MPa) and exhibit significant strain hardening (several ‰) under tensile loads. These appealing features make it a suitable material for improving the efficiency and durability of new or existing structures. However, in rehabilitation works, when a layer of a new material is applied on an existing structure, due to restraints from the existing structure, the shrinkage deformations lead to high tensile stresses in the new layer, which can lead to premature cracking. To characterize the effect of the restraining conditions, experimental investigations of evolution of autogenous shrinkage and development of eigenstresses were done using a Temperature Stress Testing Machine (TSTM) at quasi-isothermal curing conditions at 20oC, from the time of casting. Tests were done at partial and full restraint conditions to study the development of the eigenstresses. The tests with 100% restraint are the first of their kind on SH-UHPFRC and the results show that under full restraint conditions, the material enters into the strain-hardening zone of the tensile response

Everybody thinks online participation is great – for somebody else: a qualitative and quantitative analysis of perceptions and expectations of online participation in the Green Party Germany

Based on a case study from the Green Party Germany, we discuss the expectations and potential effects of the introduction of new online participation opportunities. These methods are often used in hopes of drawing in a wider group of participants, but existing literature on digital inequality suggests that this is unlikely to happen. Applying a mixed methods approach, we investigate how likely the expectations related to these new opportunities are to be met. We used semi-structure interviews to draw out what effects party members think online participation will have. We then conducted a survey asking members about their plans to change their behaviour. Comparing expectations to prospective behavioural changes, we find that the high hopes of both party members and leaders – to draw in those members who currently do not engage – are likely to be disappointed. Members who are better off, better educated, and already more active, will likely benefit more than those the party hopes to engage. We argue that this is linked to the prevailing digital divide, and that those who are targeted for more participation need to be more actively addressed to achieve broader participation

Rigid fluorinated polyimides with well-defined polystyrene/ poly(pentafluorostyrene) side chains from atom transfer radical polymerization

10.1021/ma0506435Macromolecules38187593-7600MAMO

MALDI-TOF analysis of dendrimer-like poly(ethylene oxide)s

International audienc