Experimental and molecular dynamic study on the interfacial strengthening mechanism of PE fiber/cement mortar using advanced oxidation processes

The hydrophobic and chemical inert surface properties of polyethylene (PE) fibers greatly limit its reinforcing efficiency to cement mortar. A novel surface treatment strategy, advanced oxidation processes (AOPs), which has been widely used to oxide organic debris existing in sewage, will be tentatively introduced to activate the surface properties of PE fibers by grafting oxygen functional groups. The experimental results suggest that a certain amount of hydroxyl groups can be successfully grated on PE fibers by controlling the AOPs parameters, leading to the strengthened interfacial bond of PE fiber/cement matrix and improved ductility of the composite. The tensile strain capacity of PE fibers with 5 % and 10 % hydroxyl groups reinforced cement mortar (PEOH5/Mortar and PEOH10/Mortar) is 52.4 % and 128.6 % times higher than that of the PE/Mortar. By analyzing the molecular interaction between the fiber and calcium silicate hydroxide (CSH), it is found that due to the newly formed H bond and more stable structure at the fiber/CSH interface, the interfacial potential energy of PEOH5/CSH and PEOH10/CSH is greatly enhanced by 19.1 % and 66.0 %, respectively, and a more compacted interface structure can be therefore formed, which strongly supports the strengthened interface of PEOH fiber/cement matrix. Overall, the effectiveness and feasibility of using AOPs to treat PE fibers for improving the interfacial properties of PE fiber/cement matrix are concluded, which sheds a light to develop a novel PE fiber reinforced cement mortar with enhanced ductile properties.

Automated summary

The study investigates the use of advanced oxidation processes (AOPs) to improve the reinforcing efficiency of polyethylene (PE) fibers in cement mortar. The addition of a certain amount of hydroxyl groups can enhance the interfacial bond of PE fiber/cement matrix and improve the ductility of the composite, showing higher tensile strain capacity.