What is at issue?
As the binding agent, cement is the key component of concrete. When mixed with aggregates and additives it enables the construction of houses, tunnels, bridges and many other structures. Schretter & Cie is a medium-sized enterprise in Tyrol, covering the entire production chain for cement. Limestone and marl are extracted locally in Vils and processed in the company’s own facilities. A wide range of cements is produced: regular construction cement as well as special cements for pavements and ceilings, roads, tunnels and many more applications. Fundamental knowledge and advanced physical and chemical modelling are helping the company to develop better products and make more efficient use of the raw materials locally available.
The research question
The production of cement involves firing and grinding raw materials such as limestone and marl The process might seem simple but a varity of process parameters may be adjusted: raw materials can be mixed in different proportions, fired under different conditions, the binder may be mixed with modern additives such as polypropylene or steel fibres. Which of the maltitude of possibilities is the best? How do the differences affect processing, durability and mechanical properties? Can the available raw materials be used more efficiently without compromising product quality? To answer these questions the company must expand its knowledge base. It needs a detailed understanding of the physical and chemical properties of the components and of the various steps of processing.
Cooperation in the CD Laboratory
Schretter & Cie was attracted by Prof. Lackner’s approach to material science. He is a material technologist considering “cement” and “concrete” analytically by establishing models that enable the company to develop new products. The properties of the individual components were characterized experimentally and fed into model of the processing steps. This enables optimization of the composition of the cement for each specific application, giving the favourite combination of ingredients.
Example: Efficient use of resources
Schretter & Cie operates its own quarries in Tyrol for limestone, marl and gypsum and aims to use its natural resources most efficiently. The primary goal is to save resources while maintaining raising quality, as well as making progress in other areas such as reducing CO2 emissions from the firing and grinding-process. Based on the physical and chemical descriptions and the process modelling, the company can now predict which measures could be helpful. The work within the CD-Lab has already led to the identification of promising approaches and paved the way for progress in process and material technology.
Example: Efficient tunneling
Portland quick cement is a special cement that hardens rapidly. It contains fibres and is produced by very few companies – including Schretter & Cie. The research related to a particular application in tunnel-building: tubbings are pre-fabricated cement segments used in the strengthening of tunnels. The demands on accuracy of fit are extremely high, with a margin of error of only a few millimetres. The logistics at a tunnel site requires tubbings to be delivered “just in time”. They must harden quickly, while fitting as accurately as possible. However, their production is complicated by the use of strengthening fibres. Further development requires a detailed understanding of the various processing steps. As a result of the collaboration in the CD Laboratory the company now has deeper knowledge of the manufacture of particularly suitable concrete and can put the gained knowledge into engineering practice.
