Application of the maturity method in slipforming operations
thesisposted on 08.06.2021, 07:56 by Christos Anagnostopoulos
The main objective of this thesis is to study the application of the maturity method in slipforming operations so as to provide more efficient means of the construction planning of a project. The main target of this research is to use the maturity method to establish the initial setting times and then apply those times to estimate the slipform mockup time and speed. In this research various maturity functions are compared and the most efficient one is used. The apparent activation energy (E) and the temperature sensitivity factor (B) are, examined so as to understand their effect on the maturity function and also to establish a relationship between them and the retarder dosage. Furthermore, the "FHP Strength Model (SFHP)" and the "Rate Constant Model (SkY' are used to evaluate their competence in representing the strength development of a concrete mixture in the laboratory and in the field. Also, the maturity method is used to estimate the times of mockup and then compared with the "Penetration Resistance", "2°C Temperature Increase", "Rod", and "Conductivity" methods. Furthermore, an example is presented and the mock-up times are established based on various initial concrete temperatures and slipform layer arrangements. Finally a computer program is developed to establish the mockup times, time of concrete placement, and the slipform speed during the removal process. The results of this research showed that the Carino and Tank maturity function is preferred for the calculation of the maturity indexes. Also, it is found that a linear relationship between the retarder dosage and E or B can be established. Moreover, it is shown that E or B can be estimated by the method suggested by Pinto and Hover. In addition, a new strength-maturity model is suggested. Finally, it is found that the maturity method can be used with efficiency to establish the slipform mockup times, the time of the concrete layer, and the slipform speed.