JPH09184103A - Rolling concrete paving material making use of recycled aggregate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To utilize a scrap material and to reduce a paving cost by crushing a concrete scrap material produced in construction work in specific size, mixing it as aggregate with cement, water, etc., and spreading it over the road, floor, etc., to roll. SOLUTION: A concrete scrap material is crushed with jaw crusher, impact crusher, etc., and is classified into coarse aggregate and fome aggregate and, at the same time, cement, water reducing agent, glass tiber, synthetic fiber, metal fiber, water, etc., are mixed with coarse and fine aggregate to make a paving material. The paving material is tightly spread over road, passage, floor, etc., and it tamped and rolled with vibration roller, etc. An overall amount of concrete scrap material is utilized as recycled aggregate. By the constitution, the scrap material is effectively utilized and, at the same time, pavement having sufficient strength can be obtained at a low cost.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compacted concrete pavement material using cement concrete waste material (hereinafter abbreviated as concrete waste material) generated during construction work. It can be applied to a wide range of pavements such as car roads, factory aisles, and floors.

[0002]

2. Description of the Related Art Conventionally, concrete waste generated during construction work of roads and structures is gravel for temporary roads,
It was generally used with low added value, such as backfill materials and landfill materials. Moreover, these uses did not lead to the reuse of the entire amount of the generated concrete waste materials, and it was the current situation that about half of them were landfilled. In such a situation, from the point of enforcement of the "Act on Promotion of Recycled Resource Utilization" (Recycling Law) in 1992 and depletion of aggregate resources, recycled aggregates from concrete waste are used for roadbed bones. It has come to be actively used as an aggregate for wood and concrete.

[0003]

However, when recycled aggregate is used as aggregate for concrete, recycled coarse aggregate and recycled fine aggregate have a high water absorption rate and a poor particle shape, and fine particles generated during crushing. As for water content, since it has high water absorption, there was a problem that the unit water content was large in terms of composition and the condition when concrete was kneaded became poor. Moreover, an increase in the amount of unit water leads to an increase in the amount of cement and an increase in the amount of curing drying and shrinkage, which is not preferable from the viewpoints of economic efficiency and various physical properties of concrete. Usually, the recycled coarse aggregate with sufficient mortar content is removed. It is limited to use only as a result, as a result, only about 30% of the recycled concrete is reused, and the rest is discarded or reused with low added value No such method was found.

[0004]

From the above, the inventors of the present invention have earnestly studied to solve the above-mentioned problems relating to the recycling of concrete waste materials, and as a result, waste concrete waste materials as compacted concrete pavement materials without waste. They have found that they can be effectively reused, and have completed the present invention. That is, the present invention relates to a compacted concrete pavement material in which the entire amount of waste concrete is used as recycled aggregate in a compacted concrete pavement material containing an aggregate, cement and water. Hereinafter, the present invention will be described in detail. The term "aggregate" as used in the present invention means that a concrete waste material is crushed with a jaw crusher, impact crusher, cone crusher, or the like so that the aggregate particle size is 25 to 20 m.
Coarse / fine mixed aggregate crushed to m or less, or this crushed material as coarse aggregate (25-5 mm) or fine aggregate (5
Recycled aggregate classified to ~ 0 mm). Next, the grain size of the recycled aggregate referred to in the present invention refers to the range of the actual example of the synthetic grain size of “Rolled concrete pavement technical guideline (draft)” or the coarse-grained asphalt mixture (20) according to the “asphalt pavement summary”. It is composed of continuous particle size or gap particle size that fits within the particle size range, but it is preferable to use continuous particle size because it gives strength increase due to the meshing of aggregates, and fine aggregate is 35 to 35 mm through a 5 mm sieve.
55% by mass, 20 to 50% by mass after passing through a 2.5 mm sieve
Is preferred. Next, the compounding of the compacted concrete pavement material according to the present invention means that the fine aggregate ratio is 35 to 50%, the water cement ratio is 30 to 45%, and the unit water amount is 100 to 130 kg /
It means m ³ . The reason is, looking at the fine aggregate rate,
If it is too small, material separation is likely to occur, and if it is too large, road surface properties after rolling are improved but wear resistance is deteriorated. When the water-cement ratio exceeds 45%, sufficient strength may not be obtained. On the other hand, when the water-cement ratio is less than 30%, the viscous resistance during kneading increases and the kneaded state is increased. Due to the difficulty of kneading, such as the formation of aggregates. Similarly, when the amount of water is less than 100 kg / m ³ , the state when kneading becomes too hard, and compaction cannot be sufficiently performed, and voids such as junkers are easily formed inside, and when it exceeds 130 kg / m ^3. This is because the road surface is too soft and wavy after construction, impairing the flatness. And the cement referred to in the present invention, normal, early strength, super early strength, moderate heat, various portland cements such as sulphate resistant, further, various mixed cements mixed with fly ash, silica and blast furnace slag to Portland cement. Can be used. The water referred to in the present invention may be tap water, ground water, or any other water suitable for kneading concrete. Although the main materials used for the compacted concrete pavement material of the present invention have been described above, in addition to this, lignin sulfonates, water reducing agents and polyols and oxycarboxylates as a main component and alkylallyl sulfonates and Chemical admixtures for concrete, such as high-performance water-reducing agents based on sulfonated melamine binders, as well as various admixtures such as silica stone powder, silica fume, slag powder, ceramic fine powder, stone powder, and calcium aluminate powder. Inorganic fibers such as glass fibers, rock wool and asbestos, synthetic fibers such as vinylon, nylon and acrylic, and various fibers such as steel fibers can be used. Then, as a method for producing a compacted concrete pavement material of the present invention, the main raw material is made of concrete recycled aggregate, cement, and water, mixed in a desired ratio within the above-mentioned mixing range, and charged into a conventional forced kneading mixer. A compacted concrete pavement material can be easily obtained by sufficiently kneading the mixture. The construction of the concrete pavement material produced in this way is performed by laying the compacted concrete pavement material having the above composition on a roadbed such as a grader, a bulldozer, or an asphalt paver, and then vibrating the roller or the tire roller. A method of compacting and compacting with, for example, is adopted. Hereinafter, the present invention will be described in more detail with reference to examples.

[0005]

EXAMPLE FIG. 1 shows an actual example of the particle size range of compacted concrete and the particle size distribution of the recycled aggregate used in the examples.

[0006]

[Figure-1]

The recycled aggregate shown in FIG. 1 is obtained by crushing concrete waste to an aggregate particle size of 20 mm or less. The recycled aggregate has a smooth particle size distribution curve and a downward curved continuity. doing. Moreover, it can be seen that the particle size range of the compacted concrete is satisfied. The fine aggregate ratio in the particle size distribution can be easily adjusted by changing the operating conditions of the crusher without depending on sieving and synthesis.

Table 1 shows a compounding example of the compacted concrete pavement material according to the present invention.

[0009]

[Table-1]

Table 2 shows the strength of the compacted concrete pavement material according to the present invention.

[0011]

[Table-2]

As can be seen from the results shown in Table 2, the bending strength of the compacted concrete pavement material of the present invention is 53 to 62.
Since it is kgf / cm ² (28 days old) and exceeds the standard value of the bending strength required as a concrete paving material (“cement concrete paving summary” Japan Road Association) 45 kgf / cm ² , it is usually It can be seen that it is comparable to that of the compacted concrete pavement material. Further, since the ratio of compressive strength to bending strength of the compacted concrete pavement material of the present invention is 4.6 to 6.0, which is smaller than 7 to 8 in the case of normal concrete, the bending strength with respect to the compressive strength is expressed. It can be said that it is excellent.
This is because the recycled aggregate from crushed concrete waste has a state of cement mortar attached around the coarse aggregate, resulting in more irregularities on the surface and stronger meshing between the aggregates. Can be said to be doing.

[0013]

[Table-3]

Table 3 shows the measurement results of the dry shrinkage ratio of the compacted concrete pavement material according to the present invention. As can be seen from these results, the dry shrinkage rate after 91 days has elapsed is 3.95 × 10 ⁻⁴ , which is a dry shrinkage rate of 4 to 5 × 10 4 which is the dry shrinkage rate of ordinary pavement concrete.
^Since it is close to ^-4, it can be said that the drying shrinkage ratio is comparable. The effects of the present invention are shown below.

EFFECTS OF THE INVENTION Conventionally, when the entire amount of recycled aggregate made up of waste concrete is applied to concrete, the amount of unit water greatly increases, and the condition when kneading is unfavorable. Although the aggregate was limited to only coarse aggregate, by using the compacted concrete pavement material of the present invention, it is possible to mix the entire amount of concrete waste material with a small amount of water, and with a hardened body having sufficient load-bearing capacity. It became possible to do. The effects of the present invention are shown below. (1) The entire amount of crushed concrete waste material can be used as recycled aggregate without waste. (2) Since the fine aggregate ratio can be easily changed by changing the crushing conditions, no labor, time, and sieving equipment for adjusting the particle size are required. (3) Bending strength can be improved due to the effect of meshing the recycled aggregate. (4) Since the recycled aggregate contains a large amount of fine particles, the paved surface after construction becomes dense and has excellent finish. (5) Since recycled aggregate made from waste concrete is used,
Excellent economy.

Claims (1)

[Claims] 1. A compacted concrete pavement material in which aggregate, cement and water are mixed, wherein recycled aggregate material obtained by crushing cement concrete waste material is used as the aggregate material. It is about.