Non-rigid road pavement made of local stone materials strengthened by slag alcaline binder
Authors:   M.P. Shulgin State Road Research Institute State Enterprise - DerzhdorNDI SE, Kyiv, Ukraine, Nahaichuk Vasyl 
Published: March 2021

Abstract Introduction.Road pavement is one of the most material-intensive and expensive elements of the road. The quality and durability of the road as a whole depend on the type of road construction material and the method of its application. Considering the significant needs of the road industry in construction materials, there is a need to find effective materials, the use of which allows building the road pavement that can resist the loadings of modern vehicles during the standard service life of pavement. In order to minimize the cost of construction and the negative impact on the environment, it is advisable to use local stone materials, the use of which allows obtaining the efficient road structures on their basis, requires minimal transportation costs and contributes to environmental protection.Problem statement. On the territory of Ukraine there are many deposits of stone materials and products of their associated processing in the form of crushing screenings [1–5]. These materials can be used as the stone materials for pavement layers arrangement without reinforcing binders, also for improving of their properties by strengthening with various types of binders.For strengthening and improving the properties of stone materials can be used the following:–inorganic binders, which include cement, lime and slag alkaline binder;organic binders, which include bitumen, bituminous emulsions and foamed bitumen–complex binders in the form of combination of cement with bitumen, as well as cement with bitumen emulsion or foamed bitumen.Considering the growth of transport loadings on road structures, it is necessary to provide the use of reliable and durable structures, for the construction of which it can be used available domestic raw materials. Organic binders, which include bitumen imported to Ukraine, are quite expensive and their cost is constantly rising. One of the perspective ways for solving this problem is the use of slag alkaline binders and concretes on their basis in the road construction, using local stone materials of different genesis as aggregates.Purpose. The purpose is to study the possibility of obtaining effective slag alkaline concrete with use as a mineral aggregate the stone materials of different mineralogical composition and strength, suitable for non-rigid pavement layers arrangement, capable to operate under repeated short-term loadings.Materials and methods. The erupted and sedimentary rocks that most widespread in Ukraine were used for study, namely: organic-hemogenic limestones, quartzite-like sandstones and granite materials. Blast furnace granulated slag and soda alkali flux were used as binder components. The mechanical properties and physical and chemical processes that occurred during the slag alkaline hardening were studied, and the technological parameters and the features of preparation of such concretes were studied. The state of the contact zone between the slag alkaline stone binder and various aggregates was determined by a set of methods allowed studding the physical and mechanical characteristics of the contact zone (micro hardness) and determining the distribution of the concentration of basic chemical elements in the contact zone, the composition of new formations and its microstructure.Results. The possibility of obtaining of effective slag alkaline concrete on aggregates of different mineralogical composition and strength that are suitable for non-rigid pavement layers arrangement that are capable for operating under repeated cyclic loadings, was theoretically determined and experimentally confirmed.Keywords: slag alkaline concrete, limestone, granite, sandstone, blast furnace milled granulated