High penetrating mixtures for road bases

Abstract

The state of the Russia road network requires a significant number of construction and repair measures, including those aimed at increasing the durability of road bases. A wide range of high penetrating mixtures (HPM) has been developed from composite binders (CB), crushed to S_sp = 500 m²/kg, obtained on the basis of CEM I 42.5 N of Belgorod Cement, partially replaced by technogenic resources with the addition of the superplasticizer Poliplast PFK-NLM. The viscosity characteristics of the developed mixtures indicate their high penetrating ability, because the flow time of the studied materials through the Marsh viscometer at V/B = 0.62 and a water flow rate of 140 l/m³ is 33-39 seconds. The onset of setting is at least 75 minutes, which allows for effective fastening of road pavement bases. The composite binder contributes to a significant increase in the early compressive strength of HPM (up to 56% compared to the control composition) and flexural strength (up to 75%). The ratio of tensile strength in bending and compression one of the developed compositions (on the second day is 0.13, on the seventh one is 0.11, and at grade age is 0.12) often exceeds the similar characteristic of the control composition, despite the replacement of Portland cement by more than 50 wt. % of waste from wet magnetic separation (WMS) of ferruginous quartzites, technogenic fibrous materials (TFM) and superplasticizer (SP), which indicates the development of crack resistance of the material. It was established that the deformation characteristics of the mixture hardened with CB-50SP + 1% TFM increased by 112% compared to the mixture with CEM I 42.5 N cement. Studies of the deformative properties of mixtures allow to conclude that, based on the developed HPM and crushed stone from metamorphic shales, it is possible to obtain concrete for road foundations that comply with the regulatory documentation for this type of construction. Testing of samples of reinforced crushed stone foundations for the entire range of physical and mechanical properties and operational characteristics showed that the developed HPM compositions make it possible to obtain class B5 – B10 concrete when strengthening crushed stone foundations, and they can be used in the construction of foundations of category II highways