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.

Citation:
Wijeyesekera, D.C., Loh, E.W.K. (2007) ‘Flexibility of ‘Clay Mats’ Proceedings of the AC&T, pp.238-242.