Doctoral theses of the School of Engineering at Aaltodoc (external link)
Doctoral theses of the School of Engineering are available in the open access repository maintained by Aalto, Aaltodoc.
Public defence in Civil Engineering, MSc. Teemu Ojala
Study of automated measurement methods for controlling concrete workability and improving quality control and production sustainability. Aalto University School of Engineering, Department of Civil Engineering.
When
–
Where
Otakaari 1, Espoo, auditorium U5
Event language(s)
English
Title of the thesis: Automated workability control in concrete production
Thesis defender: Teemu Ojala
Opponent: Prof. Wolfgang Kunther, DTU, Denmark
Custos: Prof. Jouni Punkki,Aalto University School of Engineering
The dissertation examines automated measurement techniques for controlling concrete workability, addressing the need for more efficient quality control systems. Traditional methods are laborious and thus can be used to measure only a fraction of the produced concrete, creating a demand for online monitoring techniques. The research focuses on critical properties of fresh concrete such as the workability, water/cement ratio, and air content. These properties must be controlled in all concrete batches to meet the requirements both in fresh and hardened concrete. The findings reveal that high-consistency concrete is susceptible for air instability and aggregate segregation in fresh state especially when modern chemical admixtures are used. To detect the segregation in fresh concrete, AC impedance spectroscopy can be used to effectively monitor segregation during compaction. While microwave absorption and time-domain reflectometry show promise in moisture detection, the acoustic method demonstrate potential for air content determination content in the fresh concrete during the mixing process. Lastly, a developed stereovision framework achieved a great accuracy in classifying concrete consistency directly in the mixer. The studied measurement techniques enable continuous monitoring without manual sampling limitations, providing real-time detection of property variations during the production. The advancements can be used to optimised mix designs with reduced tolerances, resulting in more economical and sustainable concrete production through decreased material consumption, particularly as mix designs become more complex to reduce the carbon footprint.
Keywords: fresh concrete, workability, automatic measurement, quality control, sensor
Thesis available for public display 10 days prior to the defence at Aaltodoc.
Contact information: Teemu Ojala, teemu.ojala@aalto.fi, tel. 0414546303, https://fi.linkedin.com/in/teemuojala
Doctoral theses of the School of Engineering
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