Nano boron nitride modified reactive powder concrete

This paper aims to investigate the effects of particle size and content of nano boron nitride (nano-BN) as well as curing method on the strength and durability of reactive powder concrete (RPC). The enhancing mechanisms are analyzed through performance, X-ray diffraction, nuclear magnetic resonance, thermogravimetry and scanning electron microscope tests. The flexural strength and compressive strength of RPC containing 0.5 wt% of 120 nm nano-BN achieve an increase of 2.65 MPa/15.7% and 11.61 MPa/12.96% at standard curing age of 28 d, respectively. Furthermore, heat curing for 2 d causes the increasing compressive strength of 120 nm nano-BN filled RPC, compared to standard curing for 28 d. For the durability performance, the introduction of 0.5 wt% of 120 nm nano-BN enhances the resistance of RPC with standard curing and heat curing maximally by 55.56% and 34.96%, respectively. The chloride penetration resistance of RPC containing appropriate amount of 120 nm nano-BN is improved by 100%. Experimental results show that the strengthening mechanisms of nano-BN on RPC performances are multifaceted, and can be attributed to small size, nucleation, filling, bridging, lubrication and layered blocking effects.