Effect of adding carbon nanotubes on the freeze-thaw and thermal fatigue resistance of latex modified mortar

Abstract

This paper aims to investigate the effect of adding carbon nanotubes (CNTs) on the durability of latex modified mortar (LMM). Up to 2.5% of CNTs by wt. of styrene-butadiene latex (SBR latex) CNTs were added to latex modified mortar (LMM) specimens before they are subjected to two different thermal tests: freeze-thaw and thermal fatigue. LMM specimens were subjected to a number of freeze-thaw cycles according to American Society for Testing and Materials (ASTM) C-666 in order to simulate winter outdoor conditions in the United States (US) northern areas. Also, the specimens were subjected to thermal fatigue cycles similar to summer outdoor conditions. A large number of specimens were prepared in cubes, cylinders, and prisms, and were mechanically tested in compression, splitting tension, and flexure in order to evaluate the LMM specimens after the thermal exposure. Compression and tension specimens were tested after 50% and after 100% of the total number of cycles in order to assess the effect of the number of cycles on the mechanical performance. For LMM prims, dimensional stability was assessed first by monitoring the development of shrinkage strains during the application of thermal cycles. The LMM prisms were then tested in flexure after the completion of all the thermal cycles. The effectiveness of adding CNTs was evaluated by comparing between the performance of control LMM specimens and those with different CNTs contents. CNTs were found to alter the compressive strength, tensile strength, and flexural load carrying capacity of LMM specimens.