CS259296B1 - Antifreezing synthetical aggregates into wear layer of road surfaces' and pavements' bituminous top courses - Google Patents

Abstract

The solution prevents icing and s associated slippery on bitumen roads and sidewalks in the winter months. The formation of icing is prevented by the additive chloride-containing synthetic aggregate sodium added to the bituminous wear layer road and pavement covers. The synthetic aggregate is essentially cured, crushed mixture containing by weight % to 40 to 70 wt. technical % sodium chloride, 10 to 20 wt. granite crumb 0 to 4 mm and 20 to 40 pen. wt. cement SPC 325—600. synthetic aggregate is added to the natural aggregates for bitumen production mixtures according to the desired effect in 10% or more by weight. Sightseeing thawing component - sodium chloride - it is released from synthetic for a long time aggregates due to abrasion of honest by the wheels of the means of transport.

Description

The present invention relates to antifreeze synthetic aggregate for the grinding layer of bituminous road and pavement covers.

Under certain weather conditions, in winter months, roadways and sidewalks build up ice, treasury and a layer of conglomerate snow, which increase slippery and thus reduce road safety. To prevent slippage, additives based on the freezing point of aqueous solutions are added to the bitumen coating layer.

In the Federal Republic of Germany, Switzerland, Austria, France, Denmark and the USA, a deicing agent for bituminous mixtures "Ver, glimit" is widespread.

A similar composition based on calcium chloride in the form of granules coated with a sheath of molten polymers is patented in Czechoslovakia. The product is based on a similar principle where, instead of calcium chloride, crystalline sodium chloride coated with polymer and cement dust is used. A common feature of these products is the packaging of the granular or crystalline deicing agent in a package of polymeric or inert materials. When the protective sheath is broken, the de-icing agent dissolves very quickly with rainwater, leaving a cavity in the bitumen layer to allow water to penetrate and break other layers of the mixture. This process significantly reduces the functionality and durability of the antifreeze treatment of the bituminous layer.

These drawbacks are overcome by the invention. The requirement for the gradual dissolution of the additive is met by frost synthetic aggregate, which is added to bituminous road and pavement covers. It is based on the fact that it contains sodium chloride firmly bonded by hardened cement to granite debris. Synthetic aggregates built into the abrasive bitumen cover are abraded by traffic. The exposed sodium chloride forms a solution with a reduced freezing point with air humidity or precipitation. The resulting solution prevents the formation of frost and ice, as well as the trimming of snow to the road surface, allowing better removal by mechanical means. The maximum thawing efficiency is achieved by synthetic aggregates in abrasive bituminous enclosures during precipitation in the temperature range from 0 ° C to -5 ° C.

As a result of better isolation of sodium chloride in synthetic aggregates, the additive gradually dissolves only in the abrasive bitumen layer and thus retains its flood properties until abraded. Reducing icing and facilitating snow removal from the road surface will have a positive effect on minimizing the consumption of chemical road spreading agents used for winter road maintenance.

The process for preparing synthetic aggregates containing 40-70% by weight of sodium chloride is explained in the following examples.

Example 1

Composition of the mixture in the production of 1 ton of synthetic aggregate at 40% NaCl content: troscortland cement

325 - CSN 72 2122 400 kg sodium chloride 400 kg granite grit 0–4 mm 200 kg mixing water 200 kg

Example 2

Composition of the mixture in the production of 1 tonne of synthetic aggregate at 50% sodium chloride content:

troscortland cement 400 400 kg sodium chloride 500 kg granite grit 0-4 mm 100 kg mixing water 200 kg

Example 3

Composition of the mixture in the production of 1 tonne of synthetic aggregate at 70% sodium chloride content:

troscortland cement 600 200 kg sodium chloride 700 kg granite 0-4 mm 100 kg water for mixing 200 kg

Synthetic NaCl-containing aggregate is produced by the same technological process as concrete mixtures using conventional technological equipment.

The invention can be used in the construction of abrasive layers of bituminous roofing and pavement, especially in cases where it is necessary to increase traffic safety in winter conditions. The construction of bituminous covers for roads of honor, especially highways and first- and second-class roads, as well as footpaths for pedestrians, is possible. The structural composition and percentage of synthetic aggregates in the bituminous mixture may vary according to the climatic conditions and requirements of road users.

Example 4

Antifreeze synthetic aggregate · forms part of natural aggregate in all applied fractions in bituminous mixtures. From several possible recipes for the preparation of bituminous mixtures according to the requirements for functionality and quality of road coverings, we present the optimal composition of the bituminous mixture, which was

259 laboratory tested according to ČSN 73 6149 "Asphalt concrete for road coverings":

limestone crushed 8–16 mm 22.30% granite crushed 4-8 mm 18.50% granite crushed 0-4 mm 34.20% limestone flour 3.70% sand 6.50% antifreeze synthetic aggregate 8.60% honest asphalt Petroleum A — 80 6.20%

Laboratory tests of the bitumen mixture of the above recipe, performed by an authorized organization, fully complied with the criteria of ČSN 73 6149.

Claims (1)

The anti-frost synthetic aggregate for the wear layer of bituminous road and pavement covers is characterized in that it contains sodium chloride 40 to 70% by weight and granite grit 0 to 4 mm fraction, 10 to 20 weight percent firmly bonded with cured troscortland cement 325 to 600 containing 20 to 40 weight percent.