An Experiment on Incorporation of Bentonite Clay in Mortar

Abstract

Mortar refers to a binding paste which is workable in nature and consistency, used as a binder in construction activities such as stone bonding in stone masonry, brick bonding in brick masonry and as well as in concrete works. Mortar is often used as a means for decorative works attaining to its workable nature, which in this project I have intended to enhance. Mortar is further used as a sealant in order to fill cracks and gaps within the structure. The term mortar is taken from the Latin term “mortarium” which means crushed. Mortar is often prepared by mixing a suitable binder, fine aggregate or in simpler terms sand and water by a fixed proportion by mass or volume. The ratio of the constituents depends on the quality and magnitude of the work being done. Mortar gains its strength due to the various chemical reactions that occur while the mortar is being cured in water, gaining 99% strength in 28 days. The most used binder in modern times is Portland cement, which was used at the onset of 20th century. A common binder prevailing in the past was lime and the associated mortar mix was called lime mortar. A major part of this project lies in the use of clay as a substitute for sand in mortar. Clay refers to a fine-grained soil deriving its origin from naturally occurring rocks that have undergone chemical weathering. Clay mineral can be classified into three types i.e. Kaolinite, montmorillonite and illite. The type of clay that has been used in this experiment is Bentonite which is a volcanic in origin and has montmorillonite as a major constituent. Clay has water entrapped within its structure and the amount of water depends on the type of clay mineral being dealt with. One of the major properties of clay that I have tried to exploit in this project is its plastic nature i.e. the ability of the soil to gain resistance against shear failure by sliding as they get into a dry state as opposed to possessing very little or no resistance to the same when they absorb water. Attaining help of various properties of clay, in this project I will try to evaluate the various properties of a mortar cube by mixing a fixed proportion by mass of clay in the same and present my observations