JPH02204352A - Aggregate of concrete building and production of aggregate thereof - Google Patents

Abstract

PURPOSE:To inhibit a reaction of alkali and aggregate and to prevent a crack, peeling and spalling of concrete by sticking asphalt to aggregate main body. CONSTITUTION:This aggregate A is obtained by sticking asphalt 2 to aggregate main body 1 such as gravel, crushed stone and sand. As this aggregate A, not only the whole body of aggregate 1 is coated by asphalt 2 as shown in a figure but also one part thereof is similarly coated by asphalt. When concrete obtained by kneading aggregate A with cement paste is placed, asphalt 2 stuck to the aggregate main body 1 functions as a protective layer for inhibiting reaction of alkali and aggregate. Therefore a crack, peeling and spalling of the placed concrete can be prevented. Further waste material obtained by cutting the existing asphalt paving part can be intactly utilized as the aggregate A. Therefore this aggregate A is easily produced and also fills the role of treatment of the above-mentioned waste material.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to an aggregate for concrete buildings and a method for producing the aggregate.

[Conventional technology]

Concrete used in concrete structures such as buildings and bridge girders is made by bonding aggregates such as sand, gravel, and crushed stone with cement paste, and may be mixed with AE agents, quick-setting agents, waterproofing agents, etc. as necessary. agents are mixed. This kind of concrete is reinforced with steel bars.

[Problem to be solved by the invention]

However, in concrete, alkaline components such as caustic soda and slaked lime contained in the cement paste, water, and reactive silica contained in the aggregate cause a so-called alkaline aggregate reaction, producing hydrates of sodium silicate and calcium silicate. However, the concrete may crack, peel, or even fall off. Conventionally, reactive silica and other substances were analyzed before pouring concrete, but this work was not only cumbersome but also difficult to secure aggregate.

On the other hand, when repairing paved roads, large amounts of waste materials including asphalt and aggregate are generated. This waste wood is sometimes used in landfills or mixed into asphalt mixtures in small quantities, but since the amount used in boat fishing is small, a large amount of surplus waste wood is generated, making it extremely difficult to dispose of it.

The present invention has been made in view of the above-mentioned circumstances and problems, and is capable of producing aggregates for concrete buildings that are less likely to react with alkaline aggregates and that can also play a role in the disposal of the above-mentioned waste materials. The purpose is to provide a method.

[Means for Solving the Problems] The aggregate for a concrete building according to the first invention is made by adhering asphalt to aggregate such as crushed stone.

The In method for aggregate for concrete buildings according to the second invention includes the step of producing recovered aggregate, which mainly consists of aggregate such as crushed stone with asphalt attached, by cutting an existing asphalt pavement section.

[For production]

According to the first invention, the asphalt attached to the main body of the aggregate acts as a protective layer, thereby preventing the reaction between the reactive components in the aggregate and the alkaline components of cement and water, that is, the alkaline aggregate reaction. Furthermore, when sea sand is used, the asphalt covers the salt adhering to the sand, which helps prevent salt damage caused by aggregate. It is also sufficiently effective against alkaline aggregate reactions such as alkaline ions that enter from outside, such as sea breezes and snow melting agents. In other words, it has the effect of preventing alkaline aggregate reactions caused by salt damage.

According to the second invention, a large amount of waste material generated when repairing paved roads is effectively reused as aggregate, and
The aggregate produced according to the present invention provides the same effects as the aggregate of the first invention.

〔Example〕

FIGS. 1 and 2 are explanatory diagrams showing aggregate A for a concrete building according to the first invention. As shown in the figure, aggregate A is composed of asphalt 2 attached to aggregate main body 1 such as gravel, crushed stone, and sand. Aggregate A is not limited to aggregate 1 that is entirely covered with asphalt 2 as shown in Figures 1 and 2, but also includes aggregate 1 that is partially covered with asphalt 2. It will be done. Such aggregate A
Since the waste material obtained by scraping the existing asphalt pavement can be used as it is, this aggregate A can be easily produced.

When concrete obtained by mixing the above aggregate A with cement paste is poured, the asphalt 2 adhering to the aggregate main body 1 functions as a li-retaining layer that prevents the alkaline aggregate reaction. The concrete will not crack, peel, or fall off due to the alkaline aggregate reaction, and by using waste materials generated when repairing paved roads as aggregate A, it is possible to effectively reuse waste materials. .

FIG. 3 is a process diagram showing an embodiment of the method for producing aggregate for concrete buildings according to the second invention. In this embodiment, a recovered aggregate production process, an aggregate mixing process, and an asphalt mixing process are performed in this order.

The recovered aggregate production process is a process of producing aggregate A in which asphalt 2 is attached to an aggregate main body 1 such as crushed stone by cutting an existing asphalt pavement part such as a paved road. Cutting involves scraping, heating and loosening the lumps after obtaining them, the former being produced into aggregates on-site, and the latter collecting the lumps in a factory plant and turning them into aggregates. Suitable for producing material A. The aggregate A produced in this process is not limited to the one in which the entire aggregate 1 is covered with asphalt 2 as shown in Figures 1 and 2.
It also includes a part of which is covered with asphalt 2.

The aggregate mixing step is a step of newly mixing known aggregates such as gravel, crushed stone, and sand into the aggregate A obtained in the above-mentioned recovered aggregate production step. At this time, heat is applied to mix, so excess asphalt is covered with new aggregate.

In the asphalt mixing process, aggregate A obtained in the recovered aggregate production process, newly mixed aggregate, and asphalt are kneaded, and the newly mixed aggregate and the part produced in the recovered aggregate production process are mixed. This is the process of attaching asphalt to the missing part of the covering aggregate to completely cover the aggregate with asphalt. Therefore, a heating step is generally used in all steps.

The aggregate produced through the recovered aggregate production process, aggregate mixing process, and asphalt mixing process is covered with asphalt. Therefore, when concrete is poured by mixing it with cement paste, as it is clear from the above, the asphalt covering the aggregate acts as a protective layer that prevents the alkali aggregate reaction, and the alkali aggregate is added to the concrete. No cracking, peeling, or falling off due to reaction.

Further, since the aggregate A produced in the recovered aggregate production process is the waste material itself generated when repairing paved roads, etc., it becomes possible to effectively reuse the waste material.

In addition, if sufficient strength and quantity of aggregate A is produced in the recovered aggregate production process, it is not necessarily necessary to perform the aggregate mixing process or the asphalt mixing process. Only the produced aggregate A needs to be mixed with cement paste to make concrete.

〔Effect of the invention〕

In the aggregate for concrete buildings according to the present invention, the asphalt attached to the aggregate acts as a protective layer that prevents alkaline aggregate reaction, so by mixing this aggregate with concrete and using it, the concrete becomes more stable due to the alkaline aggregate reaction. Cracks, peeling or falling off of concrete will not occur, and troublesome work such as reactive silica analysis prior to concrete placement can be omitted.

In addition, the method for producing aggregate for concrete buildings according to the present invention includes a step of producing recovered aggregate in which asphalt is attached to the aggregate, such as crushed stone, by cutting the existing asphalt pavement. A large amount of waste material generated during repair work can be effectively reused as recovered aggregate, making it possible to play a role in waste material processing. In addition, the aggregate produced by this method is mainly aggregate with asphalt attached to it, and does not cause an alkaline aggregate reaction, so concrete using this aggregate has no reactivity before it is placed. Troublesome work such as silica analysis can be omitted, and aggregates can be easily secured.

In addition, instead of the asphalt mentioned above, it is also possible to use a material that has good adhesion to cement paste and is highly water resistant.
Asphalt is the best when considering price and other factors.

[Brief explanation of the drawing]

Figures 1 and 2 are explanatory diagrams showing aggregates for concrete buildings according to the first invention, and Figure 3 is a process diagram showing an embodiment of the method for producing aggregates for concrete buildings according to the second invention. be. A... aggregate, 1... mainly aggregate, 2... asphalt.ヱ 1 Figure! J2 Figure patent applicant Obe Sangyo Co., Ltd. Agent Patent attorney Takashi Suzue

Claims (1)

[Claims] 1. Aggregate for concrete buildings, which is made by adhering asphalt to aggregate such as crushed stone. 2. A method for producing aggregates for concrete buildings, which includes a process of producing recovered aggregates mainly composed of aggregates such as crushed stone with asphalt attached by cutting existing asphalt pavement sections.