Preparation And Performance Of Acrylic Mortar Repair Materials Modified By Nano Materials Suitable For Low Temperature Environment

With the rapid development of the global economy,highways,airports,and other transportation infrastructure play an increasingly important role in the development of our country and the global economy.The increased intensity of the operation of transportation infrastructure has contributed to the development of the national economy on the one hand,and on the other hand has led to the deterioration of the coating condition of the original pavement more easily and the aggravation of pavement defects.In this case,if we want to keep the pavement open and minimize the negative economic growth caused by the suspension of pavement operation or the reduction of road throughput,we need to accelerate the rate of pavement rehabilitation,shorten the maintenance time and achieve efficient rehabilitation.At the same time,China’s seasonal permafrost area can reach 5,137,000 square kilometers,accounting for 53.5%of the country’s land area.China’s unique geographic environment and the surrounding security environment presents a serious challenge and demanding requirements for national defense security and people’s livelihood,such as airport runways,bunkers and other facilities can not be built and repaired using traditional cement concrete in extreme environments,how to quickly build and efficiently repair high-strength pavements and buildings in high cold areas is an effective guarantee for national defense security,but also to protect people’s livelihood and the solid development of economic construction solid foundation.Conventional cement concrete is a non-homogeneous and brittle material,and concrete structures are highly susceptible to damage such as cracking and even spalling under the influence of external loads and the environment.In extreme environments,the average winter temperature can reach about-25°C or even lower,causing water to freeze.Therefore,traditional cement concrete materials are no longer adequate for practical applications.Therefore,there is an urgent need for the development of materials for rapid construction and repair of pavements and buildings in extreme environments,which in turn can meet the technical needs of national defense and people’s livelihood for such materials.Highly doped repair materials based on methyl methacrylate binders are cold-curing systems,which have a wide range of curing temperatures（from-30 to-30°C）,fast hardening,high physical and mechanical properties,and other characteristics that can be applied to many important jobs.The high curing rate and the use of properties achieved can reduce the construction time and put into use quickly compared to composites with other types of adhesives,and is currently the most ideal material to meet these requirements.The effects of initiator and accelerator contents（from 3.0%to 5.0%for BPO and from 5.0%to 8.0%for DMPT）and mastic sand ratio on the curing time,compressive strength and flexural strength of the specimens under the action of benzoyl peroxide（BPO）-N,N-dimethyl-p-toluidine（DMPT）redox system at-25°C were studied in detail in this paper.Based on the optimal ratio of BPO-DMPT,the compressive strength and flexural strength of the specimens were significantly changed by changing the glue-sand ratio of the acrylate repair material.The optimal glue-sand ratio ratio at this temperature was selected by considering the economic factors,the curing time of the specimens and the physical and mechanical properties of the specimens.The physical and mechanical properties of the acrylate mortar repair materials were modified and studied using isometric,one-dimensional and two-dimensional nanomaterials as doping materials,and the results showed that the nanomaterials with all contents in almost any dimension used in this paper could improve the compressive strength of the specimens.The nano-materials of Si₃N₄,MW-CNTs,Si C and Al₂O₃ have a better effect on the compressive strength of acrylic mortar repair materials and can have a significant impact.Different contents of nano-doped materials have different effects on the improvement of flexural strength of acrylic mortar repair materials,among which the four nano-materials,Si₃N₄,MW-CNTs,B₄C and Fe₂O₃,have more obvious effects on the improvement of flexural properties of acrylic mortar repair materials and are able to produce significant effects.In order to further improve the physical and mechanical properties of nanomaterial-reinforced resin matrix composites,the three-dimensional nanomaterial Si C-OH@APTES-g-CFs-COOH was prepared by self-assembling silicon carbide（Si C）@γ-aminopropyltriethoxysilane on the surface of carbon fibers usingγ-aminopropyltriethoxysilane（APTES）treatment.The nanomaterials were subjected to FT-IR,SEM,XRD,XPS,etc.The mechanical properties of the successfully prepared three-dimensional nano-Si C-OH@APTES-g-CFs-COOH were also tested by introducing it into the acrylic mortar repair material.