Flexibility of ‘Clay Mats’

This paper presents a scientific development to addressing the current absence of a convenient technique to identify the ductile to brittle transition of clay mats. The applicability of clay mats can be brought into question if they become brittle due to drying in hot weather / tropical climates. Bentonite clay mats produced with different liquid polymers and at different moisture content were used in the study. The dependence of flexural stiffness on moisture content is presented. All the specimens showed that the flexibility of the clay mat declined exponentially with decreasing moisture content. Often one would adopt the feeling from a finger pressure test to give a perception of the softness / stiffness of the material. The paper also presents an extension of this concept to adopt an appropriately modified Brinell hardness test for the clay mats. Concurrently, 3 point bending tests were carried out on samples of the clay mat to obtain a value for the elastic structural stiffness (EI). The paper further confirms a strong correlation between Brinell Hardness Test and the structural stiffness. This study helps to assess the performance of clay mats with different proportions of additives that have been introduced in the mat manufacture to delay the inevitable drying characteristics of the mat, when exposed to hostile thermal environments