Projects / Programmes
The use of non-destructive ultrasonic method for the determination of the initial setting time of cement based materials in practice
| Code |
Science |
Field |
Subfield |
| 2.01.03 |
Engineering sciences and technologies |
Civil engineering |
Constructions in civil engineering |
| Code |
Science |
Field |
| T150 |
Technological sciences |
Material technology |
| Code |
Science |
Field |
| 2.01 |
Engineering and Technology |
Civil engineering |
cementitious materials, additives, hydration, setting, non-destructive techniques, ultrasound, artificial neural networks
Researchers (1)
| no. |
Code |
Name and surname |
Research area |
Role |
Period |
No. of publicationsNo. of publications |
| 1. |
27666 |
PhD Gregor Trtnik |
Civil engineering |
Head |
2011 - 2013 |
117 |
Organisations (1)
Abstract
Cement based materials (in the following "cementitious materials") are used more than any other man-made materials and have therefore a significant impact on the pollution of the environment, especially during the production of cement. Unfortunately, a majority of standard (destructive) tests require many test specimens to be made, which stay useless at the end of testing and thus present an additional impact on the environment. Therefore, several non-destructive ("ND") methods were developed to evaluate some properties of hardened cementitious materials. In contrast, a ND testing of fresh cementitious materials still remains a great challenge.
The proposed research project is therefore focused on the development of an appropriate ND method to evaluate the most important properties of cementitious materials at early ages directly in-situ. Two ultrasonic ("US") methods, namely US wave transmission ("USWT") and US wave reflection ("USWR") method, will be used and their ability to monitor a hydration, formation of structure and setting times of cementitious materials directly in-situ will be studied. These methods, a corresponding equipment, and a computer software were developed during a PhD project at IGMAT Building Materials Institute and successfully tested on different cementitious materials without additives under a laboratory-controlled conditions (Trtnik, 2009a).
Unfortunately, due to the several positive effects of additives in cement composites, the materials without additives are not used in an every day construction practice. Therefore, a sensitivity of the ND methods to the presence of additives in cementitious materials under actual ambient conditions has to be fulfilled in order to use these methods directly in-situ. Thus, a comprehensive study of the suitability of the proposed US methods to detect the influence of different additives and new cement types with low CO2 emission on the hydration process and formation of structure of cementitious materials at early ages under the real ambient conditions will be performed. Being the most important characteristics of fresh cementitious materials, setting times will be also taken into account, which are highly infected by the presence of additives. The possibility of using USWT and USWR methods as well as their combination to estimate the initial and final setting time of cementitious materials with additives will be therefore studied. Experimental part of the research project will be performed at IGMAT Institute as well as directly in-situ. All research equipment is available at IGMAT Institute to adequately perform the proposed project.
As an addition, a numerical model to predict the setting process of cementitious materials with additives with respect to the mixture composition and ambient conditions will be performed on the basis of the experimental results. This program will allow concrete technologists to perform an optimal recipe of the concrete mixture according to the actual ambient conditions.
The ability of these methods to detect the presence of additives under the real ambient conditions would improve the use value of the methods to a high degree and present an important step from a pure scientific research to an every day construction practice. The main contributions of the project are the possibility of the direct determination of the setting time as well as a ND continuous monitoring of the formation of structure and strength of cementitious materials with additives directly in-situ. Using the numerical model developed, one would be able to predict the hydration process, formation of structure, setting times, and compressive strength of cementitious materials with additives on the basis of the mixture composition and ambient conditions.
Results of the research project would contribute to the development of a ND setting time and hydration process determination directly in situ and would consequently present a direct impact for the economy and science.
Significance for science
It is estimated that the results of the project have several important impacts on the development of science, such as: - development of a new, non-destructive procedure, allowing accurate and unambiguous identification of setting period of arbitrary CBM, regardless of the presence of aggregates and chemical and mineral admixtures in the material’s composition (points 6.1 and 6.3), - Development of a new, non-destructive US technique, allowing analyzing the influence of various types of superplasticizers on the development of the hydration and formation of structure process of CBMs (point 6.2), - proving adequacy of the US wave reflection method for monitoring hydration and formation of structure process of CBMs and development of a numerical procedure for determination of initial and final setting time of cement pastes on the basis of the experimental results of the performed US method (point 6.4) - preparation of a review article, summarizing the most important findings in the field of US testing of early age hydration and formation of structure of different CBMs (point 6.5)
Significance for the country
We estimate that the results of the postdoc project present an important impact for the development of Slovenia, especially due to the development of a new, universal technique, allowing determination of various early age properties of CBMs simultaneously and continuously on the basis of relatively simple measurements of transmission of US P-waves through hydrating CBM. Consequently, the method would be applicable to various fields in civil engineering: • Cement manufacturing: a new universal advanced technique for monitoring various phenomena that appear during the formation of structure process, setting, and other essential properties of new cement types, • Chemical and mineral admixtures manufacturing: a new universal advanced technique to analyze the influence of different admixtures on the rate of formation of structure process, setting, and other essential properties of different CBMs, • Research laboratories, universities: a new universal advanced technique to determine the influence of the CBM's composition on various formation of structure phenomena and the development of early age properties of CBMs, • In-situ testing method: a new, advanced, non-destructive, and accurate method to determine different characteristics of CBMs directly in-situ without performing additional test specimens. Therefore, the results of the proposed project could have an important impact and will improve the design of CBMs' mixtures, contribute to the development of new materials, and allow performing more durable structures. Due to improved CBMs as well as higher quality of construction, the results will reduce the pollution of the environment (especially during the production of cement) and will contribute to a better construction scheduling. Consequently, the results will contribute to a more economical, more durable construction of higher quality, which will help civil engineering companies. This is of importance in a recession time as a slump in industrial production, investment, and construction in Slovenia continues.
Most important scientific results
Annual report
2011,
2012,
final report,
complete report on dLib.si
Most important socioeconomically and culturally relevant results
Annual report
2011,
2012,
final report,
complete report on dLib.si
