Application of thermosetting v/s thermoplastic polymeric composites and polymeric nanocomposites in cement concrete for greater sustainability

Abstract

Sustainability in cement concrete can be achieved without compromising their load carrying capacities in the probabilistic long term future. Concrete has come a long way from being a 3 phase cement-sand-stone material to a 4 or 5 phase one comprising of polymeric admixtures along with nanomaterials like carbon nanotubes (CNT) additives. Though polymers were introduced in India as late as 1980s they started to gain ground as admixtures for their various value added propositions and with the advent of nanotechnology, polymeric nanocomposites began to address many of concrete’s inherent problems not addressed before. Our Paper attempts to study the comparative effects of two different polymeric types - thermosetting v/s thermoplastics Polymeric Composites & Polymeric Nano Composites made with 1. Conventional Polymers-Melamine Formaldehyde (MF) and 2. Modern Polymers-Polycarboxylate Ether (PCE) in cement mortar matrix. The Paper reports the test results for the mechanical behaviour of ordinary cement mortar composites casted with the different types of polymers with and without nano-material additions on the medium term (28 days) as per Indian standards and long term (365 days) for sustainability issues. The polymers not only helped in adequate dispersion of the water insoluble nanomaterials through ultrasonication but also resulted in better workability of the mix. The result shows that optimized addition of polymeric CNTs (dispersed in thermoplastic PCE) gives a 37% gain in strength at 28 days & increasing the CNT % also provides for latter age (1 year) strength from 38% to 69%. It may be noted that the polymeric composites of thermosetting MF influenced a strength gain of 29% at 28 days but the addition of polymeric nanocomposites (CNTs dispersed in thermosetting MF) failed to produce any satisfactory results at 28 days and showed an appreciable loss in strength at latter ages.