Using single sided 1H nuclear magnetic resonance to investigate water absorption and stability of earth-based building materials

: There is an increasing interest in the use of earth-based building materials to improve the environmental footprint of our built environment. One of the crucial features currently limiting its use is the inferior resistance of the clay binder to water absorption and erosion. Furthermore, there is a lack of meaningful quantitative measurement methods for characterising earthen material as building material. Here, we study the water absorption into earth-based materials with 1 H single-sided nuclear magnetic resonance. Samples are prepared using an elaborate extrusion process and preconditioned under several typical moisture conditions. We demonstrate the use of the 1 H NMR technique to visualize the water absorption and to quantify the capillary water absorption. The latter increases with a more water-reducing preconditioning. Furthermore, the technique allows for the visualisation of the internal swelling of the clay binder, illustrating the strong influence of sample preconditioning.