Study On Static And Dynamic Mechanical Properties And Application Of Unsaturated Polyester Polymer Concrete

With the rapid development of China's economy,the highway traffic volume increased sharply,the demand for rapid repair of road pavement is increasingly strong in our country,hence the demand for ultra-early strong concrete is increasing year by year.Based on the research results of predecessors and actual demands,this study proposed an unsaturated polyester polymer concrete(UPPC)and steel fiber unsaturated polyester polymer concrete(SF-UPPC)which can meet the requirements of highway emergency repair construction.The static and dynamic mechanical properties of UPPC and SF-UPPC were studied,and the repair process was optimized.This paper first expounded the research significance of the subject,summarized the research status of high performance repair materials,introduced the dynamic performance testing technology of materials,optimized the UPPC proportion ratio,and carried out static and dynamic experiments and field repaired experiments of UPPC and SF-UPPC.In this paper,through uniformity experiment,orthogonal experiment and grading experiment,a series of proportion ratio optimization studies were carried out on UPPC with 6-hour cubic compressive strength over 30 MPa at room temperature and vibration-free conditions,and the optimal proportion ratio was obtained.SF-UPPC with different steel fiber content was tested.The results shown that with the increase of steel fiber content,the workability of the concrete becomes worse,and the volume content of steel fiber should not exceed 1.5%.In this paper,quasi-static compression,splitting tension and uniaxial compression experiments of UPPC with curing ages of 6 hours,3 days,7 days and 28 days and SF-UPPC with curing age of 28 days were carried out by using MATEST press machine.The experimental results shown that UPPC has high early strength,the compressive strength and splitting tensile strength of cubic specimens cured for 6 hours respective reach 40 MPa and 6.5 MPa,which are 50%~60% of the strength cured for 28 days,while the elastic modulus of UPPC is only half of that of ordinary cement concrete.With the increase of steel fiber content,the compressive strength and splitting tensile strength of the concrete increased,but the elastic modulus changed little.The modified phenomenological constitutive equations applicable to UPPC and SF-UPPC were obtained,and the error analysis was carried out.The results shown that the relative error is less than 5%,which can accurately describe material properties.In this paper,dynamic compression and splitting tensile tests of UPPC with curing ages of 6 hours,3 days,7 days and 28 days and SF-UPPC with curing age of 28 days were carried out using split Hopkinson pressure bar(SHPB)setup.The experimental results shown that this concrete is a strain rate sensitive material.With the increase of loading strain rate,the dynamic strength of the concrete increased;with the increase of curing age,the strain rate sensitivity decreased;with the addition of steel fibers,the strain rate sensitivity of the concrete decreased sharply.The results shown that the strain rate effect equation of ordinary cement concrete in European code is not applicable to UPPC and SF-UPPC,hence the empirical formula parameters were corrected and the modified empirical formulas applicable to this study were obtained.Many on-site repairing experiments has been carried out in this paper.The experimental results shown that the early strength performance of UPPC can meet emergency repairing,and can open closed traffic within 6 hours.The shrinkage of UPPC is large,which is the main factor affecting the durability after repairing.The shrinkage mainly concentrates on the chemical shrinkage during the hardening process of materials,and the negative effect of shrinkage can be weakened by post-pouring.SF0.5-UPPC has better applicability and crack resistance,SF0.5-UPPC has better durability than UPPC with the same conditions.