Discussion of the evolution of the chloride migration coefficient of Portland cement concrete tested by the rapid chloride migration (RCM) test at long-term curing periods up to 5 years
Chloride-induced corrosion of reinforced concrete is one of the main deterioration mechanisms leading to shortening of the service life of concrete structures. Therefore, assessment of the resistance of concrete to chloride ingress plays an important role in predicting the service life of such structures. The Rapid Chloride Migration (RCM) test is one of the accelerated test methods commonly used in Europe. It is commonly assumed that for a properly cured Portland cement concrete without degradation, the chloride migration coefficient should decrease with increasing curing age due to on-going hydration and microstructure densification. However, recent experiments show that the rapid chloride migration coefficient of Portland cement concrete decreases at early curing age, but increases at later curing ages up to 5 years. In this paper, the evolution of the rapid chloride migration coefficient of Portland cement concrete during long-term curing periods up to 5 years is discussed. The test conditions for the RCM test and the test results obtained from RCM tests are described. Finally, possible causes for the increase in DRCM that occurred during late curing of the samples are investigated in order to explain this increase.
Proper Characterisation of Pore Size Distribution in Cementitious Materials
In this paper, a mathematic morphology measurement with the name of opening operation was applied to section images for the assessment of pore size distribution in cement pastes. This method is compared with other methods for characterising pore size distribution, including the experimental technique of mercury intrusion porosimetry, the conventional image analysis by area histogram and a direct approach by a simulation model. The comparison study reveals that the so-called opening distribution technique yields realistic structural information of pore size distribution in cement pastes. The proper characterisation of pore size distribution is of significant importance to permeability prediction of cementitious materials and thereby to durability studies of the materials.
Human reproduction: irrational but in most cases morally defensible
While I am inclined to agree that in most cases a choice to become pregnant and bring to birth a child is an irrational choice, unlike Professor Hayry,1 I believe that choosing to do so is far from being necessarily immoral. In fact I will argue that it is often these irrational (but morally defensible) choices which make human life the valuable commodity many of us believe it is.

Hayry argues that not only is the choice to have children always an irrational choice, but also it is necessarily an immoral choice. Thus, for Hayry “human reproduction is fundamentally immoral”.1 He claims it is important to point out to prospective parents that their urge to have children is irrational. From this, he argues, it follows that once this is accepted the use of advance technologies to assist conception should be reassessed, and furthermore, the irrationality and immorality of having children should become a legitimate part of guidance given to those expressing a wish to have children.

According to Hayry the reason it is irrational and immoral to choose to bring to birth a child is that “having a child can always realistically lead to the worse possible outcome, when the alternative is not having a child”.1 He argues that when people consider having children they are faced with the choice between deciding not to have children and thus harming or benefiting no-one (this, it is argued has a value of zero), or having children where this life may be good or bad, and thus the value of this choice can be …