Comprehensive Testing Techniques for the Measurement of Shrinkage and Structural Changes of Fine-Grained Cement-Based Composites during Ageing

Barbara Kucharczyková,Libor Topolář,Dalibor Kocáb,Petr Misák,Petr Daněk

doi:10.1155/2017/3832072

Barbara Kucharczyková, Libor Topolář + Show 3 more

Open Access

https://doi.org/10.1155/2017/3832072

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Abstract

The paper deals with an experimental analysis focusing on the utilization of a specific measurement technique for determining the development of shrinkage and for monitoring structural changes in fine-grained cement-based composites during their ageing. Advanced measurement equipment and procedure allowing simultaneous measurement of length changes, mass losses, acoustic responses, and temperature development were designed and verified by the experimental investigation. The main scope of the experiments performed was focused on finding the relationships between the characteristics being investigated while maintaining a uniform test setup. For the purpose of the experimental measurement, three fine-grained cement composite mixtures were designed and manufactured. The mixtures differed in the water-to-cement ratio (w/c) and in the amount of plasticizer. The measurement outputs are presented in the form of diagrams showing the relations between the studied parameters, such as relative length changes, mass losses, temperature progress, and acoustic emission (AE) activity during solidification of the composites. The measurement results showed close relations between the examined characteristics. The progress of relative length changes together with the progress of mass losses and temperature development is reflected in the AE activity. The advanced measurement procedure and technique provided valuable information about the behaviour of cement-based composites during early setting and long-term hardening.

Highlights

The determination of the volume change development and crack formation in cement-based composites is currently receiving attention from civil engineers and concrete producers
The experimental investigation made use of advanced measurement equipment and procedure allowing the simultaneous measurement of length changes, mass losses, acoustic responses, and temperature development
The measurement of relative length changes together with the recorded progress of mass losses and temperature measured inside the test specimens provided comprehensive information about the behaviour of the material in the early stage of its setting and hardening

Summary

Introduction

The determination of the volume change development and crack formation in cement-based composites is currently receiving attention from civil engineers and concrete producers. The current testing approach is based on the earliest possible identification of disruptions in the internal structure of structural elements, which facilitates early diagnostics of the problem allowing relevant precautions to be taken in order to prevent later collapse of the structure being designed. The reason why this area is being focused on is because many problems with cracking of cement composites arise at early ages [3,4,5]. The duct contains some sound-propagation medium [8]

Experimental Part

Test Equipment and Procedures

Results and Discussion

Conclusion