Reinforcement of ultra-low dosage of polycarboxylate ether (PCE) grafted nano-silica sol to the mechanical and durable properties of cement mortar
Jianxiong Miao, Liqun Lu, Jinyang Jiang
Abstract
How good dispersion of nano-SiO2 (NS) plays a great influence on how strong reinforcing efficiency to cement-based materials. In this study, a novel nanohybrid of polycarboxylate ether (PCE) grafted nano-silica sol ([email protected]) was prepared by sol–gel methods to chemically adsorb PCE onto NSS. The developed nanohybrid showed a higher ultraviolet–visible (UV–Vis) absorbance and slower sedimentation in alkaline solutions, indicating the better dispersion and stability of [email protected] than that of untreated NSS. By this way, only 0.05 wt.% addition of [email protected] was helpful to refine the capillary pore size and reduce the total porosity of cement mortar, which in turn improved the compressive and flexural strength of cement mortar by 18.34% and 10.5% at 28 days, respectively. In addition, a reinforcing index (R index) with the ratio of strength enhancement % to dosage % was proposed, indicating that the R index of [email protected] showed 10 times higher than that of other NS-based nanomaterials reported in literatures, addressing the highly reinforcing efficiency of [email protected] to cement mortar. Furthermore, water absorption coefficient of cement mortar was therefore reduced by 12.7% with 0.2 wt.% addition of [email protected] In conclusion, such an ultra-low dosage of [email protected] with better dispersion and stability exhibited great potential to reinforce cement-based materials with highly efficiency, lower cost and reduced carbon emissions.