Water uptake in calcium carbonate-rich building materials

Please check whether enrolling in this project is possible by directly contacting the responsible supervisor(s) indicated below as soon as possible. Note that although we announce many topics, we won't be able to offer all of them simultaneously due to limited lab capacity.

Water transport in building materials (e.g., concrete, rocks) is closely related to their durability. Numerous experimental results show that water uptake in concrete has two stages, namely, fast and slow stages. It is clear that the fast stage is controlled by the capillary actions, while the slow stage may be caused by different reasons, such as slow transport in small pores, and the change of local microstructure due to the arrival of water. Our recent results show that the second stage is less obvious for carbonated concrete than the un-carbonated concrete. Our hypotheses are that (1) the microstructure of calcium carbonate is stable so it is less sensitive to water than C-S-H and CH or (2) carbonated concrete has a more uniform pore size distribution.

Lab tests will be conducted to verify our hypotheses. Carbonated concrete and calcium carbonate-rich, such as limestone and chalk, will be used for the comparison. Their microstructures will be imaged by SEM and quantified by nitrogen adsorption. Water uptake tests of these materials will be repeated several times. The student will try to find the correlations between the microstructure and different water uptake stages.

The student enrolling in this project will have the chance to learn various microstructure characterization techniques and carry out certain calculations to simulate the process of water uptake. Previous knowledge of building materials and mathematical modeling is not required.