A Novel Approach for the Rheological Behaviour of Polymer Modified Untreated and Treated Sisal Fibre Reinforced Cement Mortar Composites

Abstract

Polymers and natural fibres in cement composites have long been used in construction activities due to their prospective behaviors. The interactive effect of polymer and natural fibre in fresh cement composites will poses complex influence, which in turn directly influences the strength and durability performances. Moreover, it is implied that the study on the fresh characteristics of cement mortar composites involves multiple rheological properties. To study the rheological properties of cement mortar composites no unified tests are available to evaluate and understand the fresh behaviour. The previous studies on rheology of cement mortar as been carried out using various test equipments such as laboratory vane shear apparatus, direct shear test, flow table, mini-cone slump, LCL workabilimeter, viscometer and rheometers. The tests listed above from various literatures provided useful information on rheological behaviour in terms of flowability, cohesion, yield stress, slump and plastic viscosity. Hence in the present study, the rheological behaviour of cement mortar composites has been studied with two parameter system i.e. flow value (measures mobility of mix) and cohesion (measures stability of mix). In this investigation, rheological behaviour of polymer modified untreated and treated sisal fibre reinforced cement mortar composite for 1:3 mortar have been carried out using flow table test and vane shear test. The parameters considered in this study are water/cement ratio, Polymer dosage and fibre content with and without treatment (silica fume with polymer coating). From the results, it is noticed that the increase of fibre content decreases the flow value but, increases the cohesion of the composite. On the other hand increase of polymer content increases the flow value but, decreases the cohesion. Also, it is observed that the untreated fibre exhibited higher flow and lesser cohesion, as compared to the treated fibre composites. Regression relationships are obtained for flow value and cohesion of various mixes adopted in this study.