On The Timing of Default Losses: When and Why?

At the light of what happened in 2010 and 2011, a lot of European countries founded themselves in a difficult position where all the credit rating agencies were downgrading debt states. Problem of solvency and guarantees on the states' bond were perceived as too risky for a Monetary Union as Europe is. Fear of a contagion from Greece as well was threatening the other countries as Italy, Spain, Portugal and Ireland; while Germany and France asked for a division between risky and riskless bond in order to feel more safe. Our paper gets inspiration by Roch and Uhlig (2011), it refers to the Argentinian case examined by Arellano (2008) and examine possible interventions as monetization or bailout as proposed by Cole and Kehoe (2000). We propose a model in which a state defaults and cannot repay a fraction of the old bond; but contrary to Roch and Uhlig that where considering a one-time cost of default we consider default as an accumulation of losses, perceived as unpaid fractions of the old debts. Our contributions to literature is that default immediately imply that economy faces a bad period and, accumulating losses, government will be worse-off. We studied a function for this accumulation of debt period by period, in order to get an idea of the magnitude of this waste of resources that economy will face when experiences a default. Our thesis is that bailouts just postpone the day of reckoning (Roch, Uhlig); so it's better to default before accumulate a lot of debts. What Europe need now is the introduction of new reforms in a controlled default where the Eurozone will be saved in its whole integrity and a state could fail with the future promise of a resurrection. As experience show us, governments are not interested into reducing debts since there are ECB interventions. That clearly create a distortion between countries in the same monetary union, giving to the states just an illusion about their future debtor position.

Recycling of end of life concrete fines (0 - 4 mm) into silica and cement

The purpose of this work is to find a methodology in order to make possible the recycling of fines (0 - 4 mm) in the Construction and Demolition Waste (CDW) process. At the moment this fraction is a not desired by-product: it has high contaminant content, it has to be separated from the coarse fraction, because of its high water absorption which can affect the properties of the concrete. In fact, in some countries the use of fines recycled aggregates is highly restricted or even banned. This work is placed inside the European project C2CA (from Concrete to Cement and Clean Aggregates) and it has been held in the Faculty of Civil Engineering and Geosciences of the Technical University of Delft, in particular, in the laboratory of Resources And Recycling. This research proposes some procedures in order to close the loop of the entire recycling process. After the classification done by ADR (Advanced Dry Recovery) the two fractions "airknife" and "rotor" (that together constitute the fraction 0 - 4 mm) are inserted in a new machine that works at high temperatures. The temperatures analysed in this research are 600 °C and 750 °C, cause at that temperature it is supposed that the cement bounds become very weak. The final goal is "to clean" the coarse fraction (0,250 - 4 mm) from the cement still attached to the sand and try to concentrate the cement paste in the fraction 0 - 0,250 mm. This new set-up is able to dry the material in very few seconds, divide it into two fractions (the coarse one and the fine one) thanks to the air and increase the amount of fines (0 - 0,250 mm) promoting the attrition between the particles through a vibration device. The coarse fraction is then processed in a ball mill in order to improve the result and reach the final goal. Thanks to the high temperature it is possible to markedly reduce the milling time. The sand 0 - 2 mm, after being heated and milled is used to replace 100% of norm sand in mortar production. The results are very promising: the mortar made with recycled sand reaches an early strength, in fact the increment with respect to the mortar made with norm sand is 20% after three days and 7% after seven days. With this research it has been demonstrated that once the temperature is increased it is possible to obtain a clean coarse fraction (0,250 - 4 mm), free from cement paste that is concentrated in the fine fraction 0 - 0,250 mm. The milling time and the drying time can be largely reduced. The recycled sand shows better performance in terms of mechanical properties with respect to the natural one.