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To improve the accuracy of parameter identification and to reduce the test cost in the high-rise structure health monitoring systems , the paper proposes an optimal placement method combines genetic algorithms with improved information matrix criterion (GA-IIM). With traditional improved effective independent method (EFI-DPR), it is easily trapped into bureau of optimum solution, and the proposed method can resolve this problem. The solutions were coded by a two-dimensional integer array, each line stored a feasible solution and compulsory mutation was adopted to avoid the solution reappeared in the same position. To improve the convergence speed, each generation of optimal group was kept to the next one to participate in the competition. With the improved information matrix criterion embedded in the genetic algorithms, the placement design was produced. This technique was used to optimize the sensor placement of a nineteenth layer frame structure. Comparing the optimized sensor placement of the proposed method with that of improved effective independent method by the modal assurance criterion and the mean square error, the proposed method performs better.

Some long-term properties such as anti-carbonation properties, shrinkage, penetrability of chloride ion of fly ash concrete with nano-CaCO3 middle slurry were studied. Test results showed that the properties of anti-carbonation and impenetrability for chloride of fly ash concrete increased by adding nano-CaCO3 middle slurry because the tiny hole was filled by nano-CaCO3 and the density of concrete increased. But at the same time, the shrinkage of fly ash concrete with and without nano-CaCO3 was the same. Results of SEM also implied the hydration degree of fly ash could be increased by nano-CaCO3.

Based on designed and manufactured test equipment of concrete early age shrinkage, the influence of shrinkage reduce agent (SRA) on early age autogenous shrinkage of concrete was researched. The test results show that early age autogenous shrinkage of concrete was reduced with SRA added and the shrinkage-reducing ratio increased with concrete strength grade heightened. SRA could also greatly reduce early age autogenous shrinkage of concrete added with pulverized ly ash or slag. Superplasticizer would increse early age autogenous shrinkage of concrete, and the shrinkage was larger than those without superplasticizer, even the SRA mixed into. Furthermore, early age curing should be enhanced for concrete with superplasticizer.