ABSTRACT
The occurrence of intense rainfalls with high erosion potential in roads is expected under a climate change scenario. Malfunction or defective discharge systems may cause downslope soil erosion through scour and runoff, and therefore it is important to increase slope resilience by adopting adequate protection solutions. This paper presents an experimental study where the effectiveness of biocementation through enzymatically induced carbonate precipitation (EICP) was investigated as an alternative to a traditional solution consisting in adopting a riprap cover. Two identical small-scale slopes were built with dry uniform grading size sand in the laboratory. The first slope was treated with enzyme and the second with a calcareous rip rap cover. Both were subjected to a water thread of 0.13 l/min simulating a culvert outflow. For the enzyme-treated slope no scour or runoff erosion have occurred under this concentrated water jet, while resistance to runoff erosion was observed but scour erosion has occurred for the slope where the traditional solution was adopted. Both tests ended when the first signs of instability appeared after saturation. The two methods have prevented runoff erosion of the slopes, but only EICP prevented scour erosion, proofing the efficiency of this treatment against ravine formation. The paper ends discussing the main practical aspects of both solutions, presenting advantages and limitations.
