JPH0774088B2 - Aggregate for concrete - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aggregate for concrete which is used by mixing with cement.

[0002]

2. Description of the Related Art Regarding sand used as aggregate for concrete, sea sand has been washed with water and used as it is.
However, since such sand has a poor particle size, so-called workability such as fluidity and softness is not good when actually used by being mixed with cement, water and the like. Further, in some cases, the strength of the concrete after curing may be insufficient. Conventionally, 0.15
The sand component with a grain size of less than mm is the component of concrete aggregate
Is considered to be a sand component that does not contribute to JIS standards of 0.1.
No detailed mention is made of particle sizes below 5 mm.
It was. As a result of the research, the inventor of the present invention has been regarded as an unnecessary object
The presence of sand components with a particle size of 0.15 mm or less
Strength of REIT (reduction of concrete amount), slump,
Have come to the knowledge of giving good results to breathing
It was Natural river sand and sea sand with a fine particle size of 0.15 mm or less
Some include sand, but these are fine dust and organic matter.
Condition of sludge mixed with debris and decomposed products, dirty condition
In a state. Use as it is as aggregate for concrete
Then, dust, debris of organic matter, and decomposed products enter the concrete.
It has a bad influence on the concrete. for that reason,
Wash these natural river sands and sea sands with water to remove dust and organic matter.
The decomposed pieces are washed and eliminated before use. That water wash
In the process, sand components with a particle size of 0.15 mm or less also flowed out.
Sand component of 0.15 mm or less is lost, and 0.15 mm or less
Concrete with almost no fine sand particles below
Sand is used as an aggregate for boots.

[0003]

An object of the present invention [0005] to be Solved, workability of the concrete after casting is good, excellent workability, it is also possible to improve the concrete strength and durability after curing Moreover, it is made from natural sea sand
0.15 mm or less with no contamination of dust and organic substances
For slump and breathing with a large amount of fine-grained sand component below
It is to provide an excellent aggregate for concrete.

[0004]

Means for Solving the Problems The gist of the present invention, which has solved the above problems, is to grind sea sand having a sieve size of 0.15 mm or less and a passing rate of 4% or less to obtain a sieve size of 0.15 m.
The aggregate for concrete is characterized in that the passage rate of m or less is 5 to 15%.

[0005]

In the concrete aggregate of the present invention, sea sand having a sieve size of 0.15 mm or less and a passage rate of 4% or less is ground to make the passage rate of the sieve size of 0.15 mm or less to 5 to 15%. It is a thing. In other words, it is sand with an increased content of fine particles as a whole. Since fine-grained sand has a large surface area and easily absorbs water, it has been considered impractical because it requires a large amount of cement and water. However, fine-grained sand
The actual rate of sea sand is increased, and as a result, the amounts of water and cement used can be reduced, and concrete with good workability can be obtained. Further, the concrete strength after hardening becomes high, and the durability also increases.

[0006]

EXAMPLES Examples of the present invention will be described below with reference to the tables. Table 1 is the aggregate sieving test table, Table 2 is the particle size curve,
Table 3 is a mix design table for concrete using processed sea sand, Table 4 is a mix design table for concrete using sea sand, and Table 5 is a table showing test results.

In this example, sea sand 1 having a mesh size of 0.15 mm or less and a passage rate of 3% was ground to obtain a concrete aggregate having a mesh size of 0.15 mm or less and a passage rate of 7%. (Hereinafter, the same aggregate for concrete is processed as sea sand 2
Express). Table 1 is a sieving test table for sea sand 1 and processed sea sand 2, and Table 2 shows particle size curves for sea sand 1 and processed sea sand 2. As you can see from Tables 1 and 2, sea sand 1
Compared with, the processed sea sand 2 has a higher content rate of fine particles.

[0008] Mixture design as shown in Table 3 and Table 4 was carried out for sea sand 1 and processed sea sand 2, respectively, and surface water, slump, air amount, concrete temperature and workability were tested, and as shown in Table 5. The results were obtained. 14.5 concrete slump using sea sand 1
Whereas the concrete slump using the processed sea sand 2 is 19.0 cm, there is a difference of about 5 cm. That is, compared with concrete using sea sand 1 which is a conventional aggregate for concrete, processed sea sand 2
The workability of concrete using is greatly improved. In addition, the unit water volume decreased, and at the same time, the properties of concrete became good.

[0009]

EFFECTS OF THE INVENTION According to the present invention, it is possible to provide an aggregate for concrete which has good workability at the time of placing concrete, is excellent in workability, and can improve the strength and durability of concrete after hardening. it can.

[Table 1] It is a sieving test table of aggregate.

[Table 2] It is a table which shows a particle size curve.

[Table 3] It is a mix design table of concrete using processed sea sand.

[Table 4] It is a mix design table of concrete using sea sand.

[Table 5] It is a table which shows a test result.

[Brief description of drawings]

Claims (1)

[Claims] 1. A sieving size of 0.15 m is obtained by grinding sea sand having a sieving size of 0.15 mm or less and a passage rate of 4% or less.
Aggregate for concrete, characterized in that the passage rate of m or less is 5 to 15%.