Carbon Nanotubes Dosage Optimization for Strength Enhancement of Cementitious Composites

Abstract

Concrete is the most common used material for construction in Qatar as well as in the world. Exposure to sever environmental conditions causes physical deterioration of concrete structures and significantly affect the concrete’s strengths and modulus of elasticity. In the last decades, many improvements had been made in concrete technology. Most of these improvements focused at macro and micro level to improve the behavior of concrete. However, better enhancement in the performance of cementitious materials could be achieved at nano level where the cracks start to initiate. The development of reinforcing materials at the nanoscale has opened a new field of research within concrete technology. Nanomaterials were recently entitled to be a promising substitute to the traditional supplementary cementitious materials in order to improve the mechanical properties and the durability of cement-based materials due to its outstanding mechanical and thermal properties and unique geometrical characteristics. This research focuses on carbon nanotubes dosage optimization for strength enhancement of cementitious composites. Four dosages of carbon nanotubes; 0%, 0.05%, 0.1%, and 0.2% by weight of cement; were added into cement mortar to explore the optimum dosage that can lead to big enhancement in mechanical strengths of cementitious composites. The mechanical strengths were investigated in terms of compressive and flexural strengths. The results revealed that adding small amount of carbon nanotubes could enhance the compressive strength of cement mortar but not the flexural strength.