The performance indicators of concrete and reinforced concrete elements are constantly declining due to increased environmental aggression, the use of chemicals to prevent ice, increasing load and intensity of vehicles, temperature changes, cycles of freezing and melting water, and more.
Basalt–plastic reinforcement, which is made in Ukraine with Ukrainian raw materials, has chemical inertness and higher tensile strength compared to traditional metal reinforcement. Therefore, its use can increase the service life of rigid pavements and increase their reliability. To do so, it is necessary to determine the reliability of such structures at the design stage.
The reliability of rigid pavements with basalt–plastic reinforcement by the criterion of crack resistance is presented through the classical model of the difference between resistance and load, which takes into account the normalized Laplace function and the reliability (safety) characteristic. To ensure the crack resistance of the slab, the maximum width of the crack opening mustn't exceed the maximum allowable width , i.e. the condition of crack resistance < = 0,08.
The algorithm for assessing the reliability of rigid pavement by the crack resistance criterion consists the following steps: calculated derivatives for each member of the equation for expected crack opening width and variation coefficient of allowable crack opening Vadop, root mean square value of permissible crack opening Saдоп safety factor for crack resistance βсrc.
According to the analysis of the influence factors on the rigid pavement reliability by the criterion of crack resistance, it was found that the most influential factors include the geometry–designed cross–section: thickness of cement concrete slab, basalt–plastic reinforcement work area, its position relative to the lower facet. All these factors increase the "shoulder of the inner pair of forces".
The limit state of endurance (fatigue) for the grid pavement slab comes from the repeated action of the moving load due to fatigue reinforcement or concrete failure. The coefficient γµ is established in the work, which takes into account the ratio of the reinforcement coefficient in the section with basalt–plastic reinforcement to its usable area, which depends on the reinforcement coefficient and proposes: γ'µ = 0,8 – for cases when reinforcement coefficient is less than the useful area coefficient and γ'µ = 0,4 in otherwise cases. The engineering method of rigid pavement assessing reliability by the criterion of endurance is based on laboratory studies and features of characteristics are revealed at joint work of concrete and basalt–plastic reinforcement in the conditions of cyclic repeated loadings. It is established that the operation of basalt–plastic reinforcement rods in such conditions differs from metal and is given in the work "Algorithm for determining the fatigue strength of non–metallic rod reinforcement".
According to the results of the influence analysis of the factors on the rigid pavement reliability according to the endurance criterion, in addition to these factors (geometry of the designed section with basalt–plastic reinforcement, slab thickness, and relative area of reinforced) the cross–section loading mode is also important.
According to the tests results basalt–plastic reinforcement to determine the strength of static tensile and to determine the fatigue strength of cyclic tensile, the dependence of changes in the physical and mechanical basalt–plastic reinforcement rods characteristics under the static tension and on the cyclic repeated loading action (fatigue test). This work at the Institute of Physics and Mechanics G.V. Karpenko in L’viv in 2014 was conducted.
To test the elements reinforced with basalt–plastic reinforcement, bending, fatigue, was tested in the laboratory of the Department of Building Structures of the National University "L’viv Polytechnic". No specimen was destroyed due to fatigue. Structures with basalt–plastic reinforcement have considerable survivability. They do not collapse during the influence of 88% of crack loading at a dynamic work mode.
The field research purpose was to determine the stiffness (modulus of elasticity) and damping of oscillations on the cement–concrete slabs surface reinforced with metal reinforcement and basalt–plastic reinforcement under the impact load.
Analysis of the change of stress–strain state of rigid pavement structure depending on the cement concrete pavement thickness with and without basalt–plastic reinforcement proved that using cement–concrete pavement, reinforcement increases its reliability and inertness of such fittings.
The dissertation contains the theoretical generalization and the new solution for the scientific problem of rigid pavements effective methods calculation with basalt–plastic reinforcement.
