DE2342752C3 - Road building material and its use as a frost protection layer in road construction - Google Patents

Description

The invention relates to a road building material using melting chamber ash raw granules, which is shattered to the greatest possible extent of the cleavage of the pipe granulate and essentially in grain sizes of 0-3 mm and of fly ash.

Steam power plants with pulverized coal combustion often work with so-called melting chambers from which the slag is drawn off in liquid form, cooled in a water bath and granulated in the process. The raw granulate is under high internal tension. It is brittle and easily breaks down or breaks into smaller pieces. It is on the other hand, much worse grindable than z. B. blast furnace slag or limestone. Since the material is in If relatively large amounts arise, a suitable recycling must be sought.

It is known (DT-PS U 76 547) to prepare raw granules of the melting chamber ash in that one Subjecting raw granulate to a grinding process, which, however, is canceled as soon as a large fraction of a fine property has been received and remaining fractions, which have high grain strength; then it is separated into a fine filler and in a relatively coarser pen. The fine filler is suitable, among other things. as an aggregate for concrete.

It is also known (DT-PS 12 36 395), the crushing of the raw granulate at least up to extensive elimination of the cleavage of the melting chamber ash pellets and through this preparation process to produce a filler that has both particles the same size as the fine filler also contains particles the size of crushed sand. This material is also used for road construction suitable.

After all, it is known (DT-AS 12 28 984) to smash raw granulate from melting chamber ash, z. B. to crush in an impact mill, where one drives the crushing so far that one is essentially the entire processed melting chamber ash raw granulate has a grain size of 0-3 mm.

This material corresponds to the standardized crushed sand and is therefore eminently suitable as an additive for betaine and mortar. The material is preferred Fly ash added - The invention is based on this s prior art.

The last-mentioned material can also be used as crushed sand in road construction (Betonsiein-Zeitung, Issue 9/1965. P. 548 LSpiu letter b). For this, however, it is generally because of the

ίο considerable grinding costs too expensive. On the other hand it is Melting chamber ash granulate that is not burdened with such high processing costs, but because of its The properties described at the beginning are slightly disheveled, has also been used as an aggregate for concrete. Here, however, it can only be considered cheap Cuttings can be used with other expensive aggregates (Betonstein-Zeitung a.a.O. 546 under II). Such waste material cannot guarantee concrete of sufficient strength.

The invention is based on the recovery of considerable quantities of raw melt chamber ash granulate in high-quality concrete, in which, however, the well-known, by crushing The aggregate obtained from the melting chamber ash raw granulate to reduce the burden of the Grinding costs have a significantly lower share than before.

According to the invention, this object is achieved in that the mixture consists of 36% of the smashed melting chamber ash raw granules, 42% of melting chamber ash raw granules, 12Ψο of fly ash, 5% of cement and, in the mixed state, about 5% % consists of water.
This road building material is preferably used as a frost protection layer in road construction.

It has surprisingly been found that, despite the use of such considerable amounts of raw melt chamber ash, raw granulate contrary to the previous ideas of the experts, an increase η κ of the pressure and shear strength of the building material occurs that is based possibly on the fact that the fly ash and the smashed melting chamber ash raw granulate the Fill in the spaces between the parts of the melting chamber ash raw granulate; exist so that overall there is a considerable density. It can therefore no longer lead to a disintegration of the melting chamber ash raw granulate and the resulting conditional loss of strength come.

The invention also offers the considerable advantage that very much larger quantities of raw melt chamber ash granulate exploitable wind. This results in better waste recycling for the pulverized coal combustion possible without the waste recycling being burdened with excessive grinding costs

The road building material according to the invention can be because of the latent hydraulic properties of the Mix up the crushed granulate and the fly ash with a relatively small amount of cement. This is another economic advantage of the

ho invention.

Claims (2)

Patent claims: 1. Road building material using melting chamber ash raw granulate, which is up to extensive elimination of the switchability of the raw granulate is shattered and essentially present in grain sizes of 0-3 mm and of fly ash, characterized in that the mixture consists of 36% of the crushed melting chamber ash raw granulate, 42% Melting chamber ash raw granulate, 12% from fly ash, 5% from cement and in the mixed State consists of about 5% water 2. Use of the road building material according to claim 1 as a frost protection layer in road construction.