Erosion Behaviour of Bio-Stabilised Earthen Materials

Development of earthen building materials is one of the answers that the construction sector can provide to tackle the accelerated climate change issue. However, these materials present a wide variability, even at the local scale, and their water durability can be difficult to ensure. In order to improve their durability regarding water and avoid its prejudicial effect on earthen material’s properties, the stabilisation with bio-polymers is an increasingly studied solution. In this paper a ten-minute erosion drip test is developed and performed for various combinations of Breton earths and bio-based additions or surface treatments (linseed oil, xanthan gum, casein, alginate, vegetal varnish and tannins). The final pitting depths and eroded volumes are compared and the evolution of erosion during the test is monitored. These results are also linked to previously obtained water capillary absorption coefficients. The obtained results enable to highlight the impact of bio-based additions on erodibility of earthen materials: linseed oil and xanthan gum help to protect the earth-based samples from erosion. Other original parameters characterizing the erosion of the samples during the drip test are suggested. Limitations of this type of erosion tests are also brought out.

Influence of infiltration on soil erosion in green infrastructures

Rainwater-induced erosion in green geotechnical infrastructures such as a multilayered landfill cover system (MLCS) is a severe concern in the current era. Although vegetation is a proven measure to control erosion in the MLCS, there are other factors such as infiltration rate which influence the control of the phenomenon. Most of the existing studies are limited to understand influence of vegetation on erosion control or infiltration rate alone. In this study, an attempt is made to incorporate infiltration measurements alongside vegetation cover to understand erosion in surface layer of the MLCS. For this purpose, a pilot MLCS was constructed, and erosion of its surface soil was temporally evaluated through soil loss depth of eroded cover surface under the influence of natural as well as simulated rainfall conditions. Alongside erosion, the amount of vegetated cover was evaluated through photographic image analyses and infiltration rate was measured by mini disk infiltrometer. From the observed results, it is understood that soil erosion and infiltration rate depict a contrasting behaviour with growing vegetation. Antecedent moisture contents were observed to show greater influence on such erosion behaviour which was observed during the testing period. Such studies may be helpful to researchers and practicing engineers for understanding performance of various green geotechnical infrastructures and scheduling the maintenance services to increase the longevity of their layered soil systems.