DE3001078C2 - Binder for road construction - Google Patents

Description

The invention relates to the use of novel binders for road construction.

An important product of mineral oil refining is bitumen, which is directly or thermally modified Form is used as a binder, especially in road construction.

As a road construction binder, bitumen is derived from coal tar Products replaced because it is cheap to sell at a time when mineral oil was in abundance. coincidence; it also has a larger plasticity range the temperature sensitivity necessary for increased traffic.

Because of the worsening shortage of mineral oil and the increasing conversion of heavy refined products in gasoline and ileizöl EL fractions there will also be bottlenecks in the bitumen supply. There is therefore an urgent need Demand for binders, which, in terms of their raw material base, consist of increasingly scarce mineral oil are more independent and can replace the bituminous binders.

The bituminous binders used so far are in different classes according to the DIN standard 1995 divided according to different degrees of hardness (penetration); Depending on the penetration, there are 7 types of bitumen differentiated. The distillation bitumen is designated with a letter B and a number, which indicates the mean penetration. Have the technically most common types of bitumen in road construction a penetration of 80 to 45.

In addition to bitumen, bitumen-pitch mixtures are used today; the required bad luck will be at produced by the distillation of coal tar.

With the increasing need for bituminous binders for modern road construction, there is a Disadvantage of the previously proposed coal-based binders from the fact that coal tar pitch There is only limited availability for this purpose, as it is a high-quality raw material for the production of carbon products is used. If pitch is to be used as the sole binder component, then also the required plasticity range (difference between softening point (ring and ball) and breaking point (Fraaß)) only through complex thermal modification of the pitch (see e.g. Velske, Building materials theory - bituminous substances, Werner Verlag, Düsseldorf, 1976) achieved.

Another method of achieving the required plasticity margin has been to suspend fine Ground Kohie in coal tar pitch recommended. According to the procedures described in the literature the coal contents are up to 10% (see e.g. P. A. Bradley, Austr. Coal Ind. Res. Lab., Rep. PR 68-5, or S. Bagchee, Res. Ind. (India), 1971, 16, 102). The coal is only used to a very small extent dissolved and therefore does not serve as the actual binder component.

ίο The quality data for those used today Bitumen types are listed in the DIN standard 1995 (Table 1).

Substitution products for bitumen must have this Requirements largely correspond to a problem-free processing and strength after Ensure installation in the street.

The object of the invention was therefore to use a new binder for road construction that meets the requirements of modern road construction is sufficient and largely on the basis of raw materials available in the long term Coal is based.

According to the invention, this object is achieved by the use of a disintegration of comminuted Coal with a mixture of petrochemical and coal-based aromatic solvents with a medium one Boiling point> 350 C, optionally with the addition of other solvents, produced similar to pitch Carbon material, from which optionally up to 15% volatile components up to a boiling point of 300 C topped off and high-boiling aromatic hydrocarbon fractions of the boiling point 320-480 C in Shares of 0-30% have been added with homogenization in the heat, as a road construction binder. The percentages are understood to be percentages by weight. The desired penetration of the novel road construction binder can therefore be achieved adjust by ^ h the proportion and boiling point of the topped off more volatile components as well as through the addition and the boiling point of the highly aromatic

«Ο tar fraction.

The production of pitch-like carbon materials takes place in that one coal with aromatic residues from the steam pyrolysis of petroleum fractions in a mixture with aromatic aromatic mixtures with an average boiling point above 350 ° C as a solvent, optionally with the addition of other solvents, e.g. B. Anthracene oil, disintegrated. the Disintegration takes place at pressures of up to 50 bar and temperatures between 250 and 420 C.

5 <i Surprisingly, it has been shown that the Pitch-like carbon materials according to the invention produced predominantly on a coal-based basis important requirement criteria for bituminous road construction binders, such as penetration, softening behavior and breaking point, as described in the DIN standard 1995, meet. In particular, this is regarding the plasticity range surprising; because the pitch base previously produced directly from coal Binders do not meet the requirements for the high plasticity range of at least 50 C, but rather only show a difference between softening point (ring and ball) and breaking point (Fraaß) of 30 C.

example 1

By disintegrating 25 parts by weight of Weslerholt coal (Volatile content 37-: i8%) with 33.3 parts by weight of pyrolysis oil from the splitting of gas oil (medium

Boiling point 366 C), 25 parts by weight pitch distillate from the heat-pressure treatment (initial boiling point 275 C, 50% to 416 C) of coal tar pitch and 16.7 parts by weight filtered anthracene oil (see H. G. Franck, G. Collin; Steinkohlenteer, Springer, Berlin, 1968, Page 56) becomes a pitch-like carbon material through reaction of the solvent mixture with the coal at 370 ° C. and a reaction time of 3 hours at a maximum pressure of 20 bar. By distillation 10% volatile constituents up to 300 ° C. are separated from this carbon material

The binder obtained in this way is standardized in terms of its properties in comparison with the ones Bitumen types examined; it turns out that the binder according to the invention meets the most important requirement criteria for a bitumen corresponds to B 25 (Table 2).

Example 2

The binder prepared according to Example 1 is 82 parts with 18 parts of a high-boiling aromatic Tar fraction (boiling range 350-450 C) mixed homogeneously with heating.

The resulting binder corresponds to the most important quality criteria a bitumen B 65 (Table 2).

Example 3

25 parts by weight of a flame coal (Ensdorf, Saar, volatile content 39-40%) are 33.3 parts by weight Pyrolysis oil from the cleavage of raw gasoline (mean boiling point 358 C), 25 parts by weight of pitch distillate the heat-pressure treatment of coal tar pitch (initial boiling point 275 C, 50% to 416 C) and 16.7 parts filtered anthracene oil at 370 C and 3 h reaction time disintegrated. The maximum pressure is 45 bar.

12 parts by weight up to 300 ° C. are distilled off from the carbon material obtained in this way.

The binder obtained is mixed with 15 parts by weight of a high-boiling aromatic fraction (see at table 1

game 2) homogenized whereby a binding agent corresponding to bitumen B 45 is obtained (Table 2).

Example 4

From the pitch-like carbon material produced according to Example 3, as described above, 12 parts by weight of low-boiling components were separated off. The binder is made up of 20 parts by weight of a high-boiling point Mixture of aromatics according to Example 2 homogenized. The binder produced in this way corresponds a bitumen B 80 (Table 2).

The binders prepared according to Example 1-4 can of course also be produced by the low-boiling components are only separated off after the high-boiling aromatic fractions have been added. Particularly This procedure is advantageous when extremely high plasticity ranges are to be achieved. the Usability of a binder according to the invention with the penetration 65 is compared with bitumen B 65 tested on a mineral mixture for the production of an asphalt-concrete mix.

One exhibits

15% Baialt high-grade gravel
18% basalt fine chippings
18% basalt fine chippings
25% basalt crushed sand
17% natural sand
7% limestone powder

8/11 mm
5/8 mm
2/5 mm
0/2 mm
0/2 mm

100%

and 7.2 parts by weight (based on 100 parts by weight of the mix) of the binder prepared according to Example 2 produces an asphalt-concrete mix, this results in a Marshall stability of 20.0 kN according to DIN 1996.

A corresponding Marshall body, made from the same mine; al mixture and a bitumen B 65 on the other hand results in a Marshall stability of only 11.1 kN.

This shows the excellent resistance to deformation of the binders according to the invention.

ί Type of bitumen Road construction bitumen DIN B 200 1995 B 65 B 45 B 25 B 15 ■ " B 300 160-210 B 80 50-75 35-50 20-30 10-20 '■; Penetration, V _n , mm 250-320 37-44 70-100 49-54 54-59 59-67 67-62 Softening point 27-37 44-49 ; (Ring and ball), c -15 -8th -6 -2 +3 Fraass breaking point -20 -10 max., C

Table 2

Road construction binders through disintegration of coal

binder binder binder binder according to according to according to according to example 1 Example 2 Example 3 Example 4 Penetration, V ₁₁ , mm 24 65 45 98 Softening point (ring and ball), C. 65 52 56 48 Breaking point according to Fraaß, C. -4 -10 -8th -12 Plasticity range, C 69 62 64 60 Corresponding bitumen type B 25 B 65 B 45 B 80

Claims (1)

Claim: Use of a by disintegration of crushed coal with a mixture of petro- and coal-derived aromatic solvents with a medium boiling point > 35O C, optionally with the addition of other solvents, produced Pitch-like carbon material, from which up to 15% of the volatile Shares up to a boiling point of 300 C and high-boiling aromatic hydrocarbon fractions the Siedelage 320-480 C have been added in proportions of 0-30% with homogenization in the heat, as a road construction binder.