Morphological Evaluation of Surface Degradation and Mechanical Properties of Compressed-Earth Blocks (CEB)

Earth architecture has been an ecological alternative since the surrounding materials can be used.The durability of earth elements such as compressed-earth blocks (a soil brick) is less than that of traditional blocks.In the present work, the evaluation of weathered earth-based walls was carried out after six years in the mid-region of the Gulf of Mexico coast (Tampico, Tamaulipas, Mexico) and contrasted with sections of compressed earth block without environmental degradation.The blocks were fabricated from two different blends with the following materials: (A) 50.4% clay soil (Altamira, Tamaulipas, Mexico), 38.4% Medrano sand, 6.4% cement, and 4.8% nopal mucilage aqueous solution (1:10).(B) 50% clay soil, 35% cement, 10% lime, and 5% nopal mucilage aqueous solution.A stochastic model was developed from image analysis to understand the biofilm formation process, and the modification of the compressive strength was evaluated.It was found that the compressive strength decreases (up to 65%) due to degradation.The CEBs stabilized with lime showed no surface changes, and there were no changes in the strength properties.For the cases in which there was degradation, it the fractal dimension and the respective specific surface area were found to have increased.This work can improve the perception of using this material in Mexico's regions, where the humidity levels are potentially dangerous for the earthen structures.Besides, it offers a non-destructive methodology to determine the deterioration of housing walls built with earth elements.