Abstract: In civil engineering construction, mass concreting of a thick foundation slab is not uncommon. The non-stop operation could lead to elevated temperature above 90°C. It is derived from the exothermic chemical reaction. The elevated temperature favors the delayed Ettringite crystal formation, which would generate micro-cracks and hence deteriorate the strength of concrete. This paper presents a review and a project to validate the delayed Ettringite degradation through a simulated laboratory environment.

• Publication Date: 22-Feb-2015
• DOI: 10.15224/978-1-63248-039-2-29
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Abstract: The nondominated sorting genetic algorithm with elitism (NSGA-II) is widely used due to its good performance on solving multiobjective optimization problems. In each iteration of NSGA-II, truncation selection is performed based on the rank and crowding distance of each solution. There are, however, drawbacks in this process. These drawbacks to some extent cause overlapping solutions in the population and have an affection on the spread of nondominated solutions, which reduces the diversity of the obtained solution set. In this paper, 4 causes for generation of the overlapping solutions are investigated firstly. A new technique for alleviating this phenomenon is incorporated to enhance the capability of NSGA-II. The improved algorithm is referred to as NSGA-II+ in this paper. In NSGA-II+, overlapping solutions are removed during the truncation selection from the merged population (which is a combination of parent population and offspring population) after ranking in each iteration. The

• Publication Date: 22-Feb-2015
• DOI: 10.15224/978-1-63248-039-2-30
• Views: 0
• Downloads: 0