РОЗРОБКА ПОЛІМЕРНИХ НАПОВНЕНИХ КОМПОЗИЦІЙ ДЛЯ РЕМОНТУ ШТУЧНИХ СПОРУД ЗАЛІЗНИЧНОГО ТРАНСПОРТУ

Purpose. The article aims the study of the impact the filler content on the bending and compressive strength of polymer materials, determination of the optimal amount of filler, design and application of the composition for the repair of concrete infrastructure objects. Methodology. The strength of the filled polymer composite material was determined by testing the beam samples with dimensions of 40 mm ´ 40 mm ´ 160 mm for compression and bending. The graphic dependencies between strength and different amounts of filler in 50, 100, 150 and 200 mass parts from the total volume of the composition were found. As a filler, the fraction with particle size less than 0.14 mm, obtained as a result of grinding waste of railway reinforced concrete sleepers, was used. Findings. It was established that the dependences of strength during bending and compression have a non-linear character when the amount of filler in the composition increases. The biggest strength both in bending and in compression is demonstrated by samples containing 100 parts by mass of recycled fine filler – 28.5 MPa and 114.0 MPa, respectively, which is compared to the strength of pure polymer (30.0 MPa and 100.5 MPa). Increasing the share of concrete grinding waste in the polymer composition to 200 wt. parts led to a 7-fold decrease in the compressive strength of the polymer solution, and a 2-fold decrease in the bending strength. Originality. The obtained dependencies reveal the mechanism of structure formation in filled compositions, where recycled waste from crushed concrete structures is used as a filler. The smaller the size of the filler particles, the greater their specific surface area and the greater their role in the formation of the interfacial interaction surface. When the number of filler particles increases, the porosity of the material increases too, including due to the porosity of the recycle aggregate itself. It leads to a decrease in its strength and ability to elastic reversible deformation. The resulting dependencies provide a basis for creating calculation models to determine the compositions of polymer composite filled materials considering the aggregate grading of filler. Practical value. The use of crushed waste from destroyed concrete structures as fillers will ensure the reuse and disposal of such waste. The introduction of fine filler into the composition of polymer composite materials will reduce the cost of such materials for repair work and restoration of infrastructure facilities, increase the durability of repaired structures, and reduce the time between repairs.