RU2163610C2 - Method of preparing sulfur-asphalt-concrete - Google Patents

Abstract

FIELD: building materials industry, more particularly coatings of highways, aerodromes, sport grounds, automobile parking areas. SUBSTANCE: method comprises reacting sulfur with dicyclopentadiene and subsequently mixing modified sulfur with bitumen and filler. Reaction of sulfur with dicyclopentadiene is carried out by stirring the whole with submerged sulfur pump for 45-60 min at 140-145 C. Sulfur bitumen is then prepared by intensively stirring modified sulfur and bitumen in reactor for 25-35 min at ratios from 1:1 to 1:5 and subsequently mixing the resulting sulfur-bitumen with mineral filler. Dicyclopentadiene is added in amount of 1.8-2.5 wt.%. EFFECT: improved physico-mechanical properties of asphalt-concrete by varying parameters conditions and parameters of production process. 5 cl, 2 ex

Description

 The invention relates to building materials, in particular to asphalt mixtures used for paving roads, airfields, sports fields, car parks, etc.

 There is a method of producing an asphalt concrete mixture [1] by mixing heated bitumen with sulfur-containing waste in a ratio of 1: 0.9-1.3, followed by mixing the resulting binder with heated mineral material, which is used as crushed stone, gravel, and stone tile grinding waste quartz sand fraction 0.05-5 mm in a ratio of 1.2-1.8: 1. With final mixing, waste can be added to the mixture in a ratio of 1: 3.6-5.4, which is a waste product of a state district power station.

 However, according to the known method, sulfur-containing wastes, for example, filter cake, available only in plants for the production of sulfur from ore, are transported economically to concrete plants. Used sulfur-containing waste in a known method must be dried from 12 to 15 wt.% Up to 0.5-1 wt.%. In addition, they contain a significant amount of marl, which adversely affects the quality of the resulting asphalt concrete, in particular, reduces the adhesion of a solid mineral filler with a binder.

 The closest technical solution to the claimed is a method of producing asphalt concrete [2], including the interaction of sulfur with dicyclopentadiene, followed by mixing modified sulfur with road bitumen and mineral filler. The resulting composition contains a fibrous filler, which is used as fiberglass or asbestos, as well as an inorganic filler, such as talc, etc. The amount of sulfuric system in the composition is from 1.25 to 25 parts per 1 part of bitumen. Sulfur system includes from 50 to 97 wt.% Sulfur, 1 - 10% dicyclopentadiene, 1 - 5% fiberglass, 1 - 20% powdered inorganic filler.

 The disadvantages of the known method for producing asphalt concrete are that when sulfur is supplied to the mixer simultaneously with bitumen and filler, where the mixing time is 1-2 minutes, a mechanical mixture of components is obtained, the physico-mechanical characteristics of which will be lower in comparison with the composition obtained by preliminary intensive mixing of sulfur and bitumen.

 Also, according to the known method, the modified sulfur is pre-mixed with the filler, in connection with which the kinematic viscosity of the mixture increases, which complicates further transportation and mixing with other components. The presence of the stage of preliminary mixing of sulfur with the filler necessitates an additional unit, which also complicates and increases the cost of the technological process as a whole and requires the reconstruction of existing asphalt plants.

 The basis of the invention is the task of improving the technology for producing asphalt in the direction of improving its physical and mechanical properties by changing the conditions and parameters of the process.

The problem is solved in that in the method for producing sulfur-asphalt concrete, comprising the interaction of sulfur with dicyclopentadiene followed by mixing of modified sulfur with bitumen and a filler, according to the invention, the interaction of sulfur with dicyclopentadiene is carried out by intensive mixing with a submersible sulfur pump for 45-60 minutes at a temperature of 140 - 145 ^o C, then pre-receive sulfur bitumen by mixing in the reactor modified sulfur and bitumen for 25 to 35 minutes at a ratio of 1: 1 to 1: 1.5 followed by by mixing the obtained sulfur bitumen with a mineral filler.

 Dicyclopentadiene is administered in an amount of 1.5 to 2.5 wt.%.

 Serobitum is introduced in an amount at which its volume concentration corresponds to the volume concentration of ordinary bitumen for a given brand of concrete and type of filler.

 The preliminary production of sulfur bitumen by mixing sulfur and bitumen in the reactor for 25 - 35 minutes ensures the implementation of chemical reactions between sulfur and bitumen components, which increases the plasticity of the material, reduces penitration and increases ductility, providing a generally high quality of the resulting asphalt concrete.

 The ratio of the modified sulfur and bitumen is justified by the obtained optimal indicators, in particular, the softening temperature and the foaming of the sulfur-bitumen mixture.

 Thus, the set of essential features of the claimed invention ensures the achievement of the specified technical result.

 To achieve the industrial applicability of the invention and the possibility of achieving the specified technical result, we present the sequence of operations of the technological process and an example of a specific implementation of the method.

 The method is as follows.

 The technological scheme for producing sulfur-bitumen asphalt concrete includes: a modified sulfur production unit, a sulfur-bitumen preparation unit, and a standard factory installation for producing asphalt concrete. The installation works in the same mode as when receiving asphalt concrete based on bitumen binder.

Modified sulfur is obtained by mixing sulfur and DCPD using a submersible sulfur pump. Moreover, the DCPD is fed to the suction of the pump, operating bypass in the amount of 2 ± 0.5% weight by weight of sulfur. The temperature of the reaction 142 - 145 ^o C. the Time of the reaction 15 - 45 minutes Sulfur bitumen based on modified sulfur and bitumen is produced in the same way as modified sulfur using a bypass bitumen pump. The sulfur content in the mixture is 40 ± 2 wt.%. The temperature with stirring the mixture 145 ± 5 ^o C. the Mixing time 30 ± 5 minutes A homogeneous mixture of sulfur-bitumen is stored in the same reactor with subsequent stirring with a stirrer with a speed of 60-100 rpm. The prepared mixture is pumped to the mixer for the preparation of asphalt concrete with a bitumen pump, and mineral fillers are also supplied here, and the dispersed composition of the filler is determined and prepared in accordance with the brand of the required sulfur-asphalt concrete. The temperature of the solid filler 145 - 150 ^o C. the Mixing time in the mixer 45-120 ^o C.

 The amount of binder is selected from the condition that the volume concentration of the sulfur-bitumen binder is equal to the volume concentration of the bitumen binder for this type of filler.

Case Studies
Example 1

 Serobitum is prepared on the basis of paraffin bitumen grade BND 90/130 and gas sulfur modified with dicyclopentadiene.

Modified sulfur includes 1 ± 2 wt.% Dicyclopentadiene. The modification time is 345 minutes, the reaction temperature is 145 ± 2 ^o C. The time to obtain sulfur bitumen is 30 minutes. The temperature of the mixture is 145-146 ^o C.

 The test results are given in table. 1.

 Example 2

 Serobitum is prepared on the basis of BND 40/60 bitumen and modified gas sulfur.

 The test results are given in table. 2.

 Analysis of the results of the table. 2 indicates that the proposed method for producing sulfur-asphalt concrete provides sulfur bitumen suitable for road construction.

 The preparation of the asphalt mix by the proposed method does not require additional devices and appliances and can be used in conventional asphalt plants.

 The prepared samples from the proposed sulfur-asphalt concrete were tested by the road laboratory in Astrakhan. Test specimens meet the requirements of category G and D asphalt concrete.

 The test results are given in table. 3.

 Samples were prepared on the basis of bitumen grade BND 90/130 and sand and gravel in accordance with GOST 12801-84. Form d = 50.5.

When using sulfur gas and modified, the temperature of the filler and binder did not exceed 150 ^o C.

 The water resistance coefficient of sulfur-asphalt concrete obtained using modified sulfur is 0.72 - 0.75 and 0.64 - 0.68 with prolonged water saturation.

Claims (2)

1. A method of producing sulfur-asphalt concrete, comprising reacting sulfur with dicyclopentadiene followed by mixing modified sulfur with bitumen and a filler, characterized in that the interaction of sulfur with dicyclopentadiene is carried out by vigorous stirring with a submersible sulfur pump for 45-60 minutes at 140-145 ^° C, then serobitumen is preliminarily obtained by mixing in the reactor modified sulfur and bitumen for 25 - 35 minutes at a ratio of 1: 1 to 1: 1.5, followed by mixing the obtained sulfur bitumen with mineral nym filler, wherein serobitum administered in an amount that the concentration of its volume corresponds to the volume of an ordinary concentration for a given grade of bitumen and filler concrete type.  2. The method according to claim 1, characterized in that dicyclopentadiene is administered in an amount of 1.5 to 2.5 wt.%.

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