Multilevel inverter consists of base cells that have the same structure as active power line conditioner. This allows to use the inverter cells as the VAR-compensator in uninterruptible power supply systems. The advantage of this system is increasing the allowable current range that can be correctly compensated. All the necessary changes for such mode provides control system algorithm only. Keywords-uninterruptible power supply; multilevel inverter; compensation; active power line conditioner.I.

No abstract

The standard methods for testing road pavements by loading have been widely applied to assess the road pavements maintenance during design, construction and survey stages and especially for the Pavement Management System purposes. These test methods were classified by the type of an applied load as static loading, cyclic loading or impulse loading tests. The paper reviews the above mentioned test methods from the aspects of their scopes, advantages, and general requirements for testing in accordance with the world-wide experience in road building industry. Static loading shall be positioned as the simplest and low-cost test method that permits the testing of relatively thick pavement constructions but does not allow the measurements of deflection bowl. Cyclic loading is more convenient for thinner pavements testing and, together with surface moduli, permits the measurements of deflection bowl. Impulse loading is the most representative test method that simulates traffic loading most adequately and permits the deflection bowl measurements as well. Impulse load can be applied using “high-weigh” device such as falling weight deflectometer, or light weight deflectometer thus given the possibility for testing road pavements with a monolithic upper layer or an unbound layer (base layer, sub-base, sub-grade layer). Standard methods for testing road pavements by loading were widely implemented to measure the surface moduli, the deflection bowl values and also, for rigid pavements, the load transfer efficiency in an area of joint or crack. Surface moduli and deflection bowl values are effectively used, mainly through the back-calculation processes, to assess the stiffness of pavement layers, the life span of road pavements and also for the project or network level testing of road pavements. These tasks rise as high actual for Ukraine intended to be integrated in the EU transport system, where trucks weighing up to 40 tonnes are permitted for international hauling. Considering the necessity for expansion of network level testing to assess the bearing capacity of road pavements and to set restrictions for trafficking at some critical conditions especially seasonal those, the conclusions state the need to process related national standards as national normative documents aiming on: – implementation of standard international classification of methods for testing the road pavements by loading considering the type of loading; – widening the requirements for proceeding of tests; – improvement the pavement management system. Keywords: road pavement; non-destructive testing; static loading; cyclic loading; dynamic loading.

No abstract

Introduction. This paper presents the results of the standardization of requirements for granular mixtures bound by mineral binders for bases, sub-bases and top layers of road pavements used as framework for national standard «Crushed stone materials and gravel materials for the road building industry — Specifications. Part 3: The materials bound by mineral binders». Standardization. The standard covers the requirements for crushed stone-sand and sand-gravel mixtures treated with mineral binders and derived from them hardened materials as well as the requirements for source constituents. Mineral binder for the standardized type of road materials shall be selected from following main constituents: cement, slag or fly ash each separately or combinations thereof using an activator if required. Standard mixtures shall be produced in a factory or mixed in situ on the road surface. Clauses of the standard also comprise the requirements for mixtures and related hardened materials from active slag or ash-slag materials which can act as the main constituent of the mixture (aggregate) and part of the binder. Standardized mandatory characteristics include mixtures physical properties comprising grading envelopes, and mechanical properties; the obligatory sections of the standard include requirements on quality control, transporting and marking of mixtures. Conclusions. Conclusions outline main results of standardization in view of the ongoing works on processing the related European Norms as national normative documents. It is emphasized that the developed standard supplements the fundamental requirements of adapted European normative documents regarding the composition and properties of said mixtures, particularly the requirements on frost resistance. The subsequent work shall be aimed at the adaptation of national regulations on road pavement design and construction to implement the newly standardized requirements for hydraulically bound mixtures.