DOI: 10.33868/0365-8392-2020-4-264-47-51
© Serhii Holovko, PhD, Senior Research Officer, e-mail: vdo@dorndi.org.ua, ORCID: 0000-0002-9517-7049
(M. P. Shulgin State Road Research Institute State Enterprise)
A NEW APPROACH TO REPAIR OF NON-RIGID ROAD PAVEMENT TRANSITIONAL TYPE
Abstract. Earlier, due to insufficient financing of the road industry, funds were allocated on a leftover basis for the repair of local roads, over time the condition of these roads has deteriorated significantly. So, given the ramified network of local roads, the issue of restoring the condition of local roads is a very urgent problem.
Conducted exploratory studies of the application of stabilization technology to restore the condition of local roads show that this technology is progressive, since it allows reusing existing materials while ensuring the required strength of the pavement. However, design engineers rarely use this technology, probably due to insufficient research on this approach. The task is to investigate the possibility of using stabilization technology with the use of crushed stone layers of different composition and their maximum reuse, when repairing transitional pavements.
Analysis shows that there are many cases where transitional structures have significant heterogeneity and low strength. This is formed due to a weak crushed stone base and waterlogging of the subgrade soils. Over time, soil particles penetrate into the crushed stone layer and weaken the contacts between the crushed stones, as a result of which rut, pits and subsidence form on the road, which significantly complicates the movement of vehicles.
Studies of the composition of existing bases show that if in a dispersed system the amount of crushed stone grains is more than 50% by volume, then a contact frame is formed in the material. Intergranular voids are filled with soil or fine aggregate, processing with such a small amount of a mineral binder (cement or lime) allows it to be significantly strengthened, as well as to create bonds between the soil and crushed stone.
Modern self-propelled soil mixing machines (recycler-stabilizer) allow in one pass to perform milling (loosening) and mixing of materials of existing transitional pavement to a depth of 40 cm. Taking into account the dependence of the distribution of normal stress in a two-layer half-space, it can be seen that stabilization of the foundation to a depth of 40 cm will allow the subgrade soil to work without exceeding the permissible shear deformations.
The construction of the experimental site in Berezivka, Odessa region, confirmed the assumptions about the effectiveness of the proposed solution to restore the strength of transitional pavement.
Keywords: non-rigid pavement of transition type, modulus of elasticity, stabilization, rubble, soil, cold recycling.
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