JPH07291760A - Lightweight concrete for filling and lightweight hardened material thereof - Google Patents

Abstract

PURPOSE:To facilitate the measure and the control of the ratio of water to cement, prevent the fluctuation of quality, reduce the weight of building and improve the durability four kinds of mixed raw materials such as cement, water, a high performance AE water reducing agent and a lightweight fine aggregate. CONSTITUTION:The high performance AE water reducing agent is capable of controlling the ratio of water to cement in the concrete to <=40% and keeping the fluidity of the concrete for a long time with both action of the water reducing agent and a dispersing agent and greatly reducing to 20-30% of unit quantity of water without affecting an adverse effect on the hydration reaction of cement and the lightweight concrete for filling is obtained by using a synthetic resin foamed bead such as a polystyrene foamed bead having 0.1-1.5mm average particle diameter and 0.2-0.05 average true specific gravity as the lightweight fine aggregate of one of the mixed material. A lightweight hardened material 1000-1500kg/m<2> in mass per unit volume is obtained by hardening the lightweight concrete for filling.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lightweight concrete for filling using a high-performance AE water reducing agent or synthetic resin foam beads and a lightweight cured product thereof.

[0002]

2. Description of the Related Art Conventionally, sand has been generally used as a fine aggregate for concrete.

[0003]

However, since sand has a high water absorption rate, has many irregularities, and has a large surface area per unit volume due to its fineness, a large amount of surface water is brought in, making it difficult to measure and control the water-cement ratio. However, there is a problem that quality variation easily occurs. Moreover, the true specific gravity of sand is about 2.6, which is one of the causes of increasing the specific gravity of concrete to about 2.3.
As a result, there is a problem that the weight of the building is increased. Furthermore, there is a shortage of high-quality sand, and as a result, sea sand is often used, and the salt content causes rusting on the reinforcing bars, resulting in a decrease in durability.

[0004]

The present invention has been made to solve the above-mentioned problems, and the means to be solved by the present invention are, in claims 1 to 4, at least cement, water and high performance. The AE water-reducing agent and the lightweight fine aggregate are made of lightweight concrete for filling using four kinds of mixed materials of synthetic resin foam beads having an average particle size of 0.1 to 1.5 mm. It is a polystyrene foam bead, and the average true specific gravity of the polystyrene foam bead is in the range of 0.2 to 0.05, and the water-cement ratio of concrete is 40.
% Or less.

According to a fifth aspect of the present invention, at least a synthetic resin foam bead is used as one of the mixing materials to obtain a light-weight cured product whose unit volume mass is in the range of 1,000 to 1,500 Kg / m ³ .

[0006]

The high-performance AE water reducing agent has a long time for maintaining the fluidity of concrete, has both the action of the water reducing agent and the action of the dispersant, does not impair the cement hydration reaction, and has a unit water content of 20 to 20%. It can be greatly reduced in the range of 30%, and has recently been applied to various uses.

[0007] The synthetic resin foam beads have almost no water absorption, and since they are spherical, they can be stored in a dry state, and both volume and weight can be measured.
It is easy to measure and control the water-cement ratio, the variation in the quality of concrete can be made very small, and concrete of constant quality can be obtained.

Further, since it has a spherical shape and has no surface irregularities and a small water absorption rate, the fluidity of concrete is improved, and the amount of water can be reduced by that much, thus improving the quality of concrete. You can In particular, the neutralization performance, watertightness, and freeze-thaw resistance are improved.

Since the synthetic resin foam beads are used, the specific gravity of concrete (usually 2.3) can be reduced. Even when gravel is used as the coarse aggregate, the specific gravity is about 1.85, and the artificial lightweight material for structure is used. In that case, the specific gravity can be reduced to about 1.4.

When the synthetic resin expanded beads having a particle diameter of 1.5 mm or more are used, buoyancy is generated in the synthetic resin expanded beads in a fluid state, and the synthetic resin expanded beads are floated and separated, so that they cannot be mixed, which is not preferable. Therefore, it was set to 1.5 mm or less.

The synthetic resin foam beads can be obtained by foaming polystyrene, polypropylene, polyethylene, acrylnitrite polystyrene, polystyrene-polyethylene copolymer, polyvinylidene chloride or the like. The expansion ratio is not particularly limited, but is usually about 5 to 20 times. Even with such a foaming ratio, it is slightly shrunk in the lightweight concrete, and the degree of shrinkage is greater as the expansion ratio is higher.

[0012] The high-performance AE water reducing agent and synthetic resin foam beads as described above are added to cement as water and a hydraulic binder to form concrete. In addition to this, fine aggregate, coarse aggregate, admixture, etc. Mixing other ingredients can be freely selected according to need. Also, the mixing ratio of each of these materials can be appropriately adjusted according to the purpose of use of the concrete.

When polystyrene expanded beads are used among the above raw materials, the strength of concrete is further increased due to the toughness of polystyrene.

The average true specific gravity of the expanded polystyrene beads is in the range of 0.2 to 0.05, more preferably around 0.1. When the average true specific gravity is 0.05 or less, the strength of the hardened concrete is reduced by about 20 to 30%, and when the fluidized concrete is pressure-fed, it is compacted and the density tends to be high. On the contrary, if the average true specific gravity is 0.2 or more, the strength of the hardened concrete is lowered and the nonflammability is also lowered. Therefore, the above range is preferable, but even if it exceeds these ranges, it is not practically used. It is something that can be done for a while. Here, the true specific gravity means the specific gravity before mixing with cement, and the average true specific gravity means the average specific gravity of all polystyrene foam beads to be mixed.

A water-cement ratio (W / C) of 40% or less, preferably about 25 to 35%, shows good performance. When the water-cement ratio is 40% or more, the compressive strength and the drying shrinkage performance are deteriorated, which is not preferable. The water cement ratio can be further reduced by using blast furnace slag or the like in addition to the high performance AE water reducing agent. In general, the smaller the size, the better the performance. However, if the size is too small, that is, 25% or less, the viscosity becomes high, and the kneading, pumping performance, etc. are deteriorated and the workability is deteriorated. However, since the water-cement ratio can be freely changed and used in the case of a special use application, the water-cement ratio shown above shows a preferable range in a generally used state. is there.

As the cement, blast furnace cement, silica cement, fly ash cement and the like can be used in addition to Portland cement such as normal Portland cement and early strength Portland cement, and it is preferable to use them depending on the application.

When a synthetic resin foam crushed product is used instead of the synthetic resin expanded beads, the strength of the hardened concrete is reduced by about 30 to 50% and the fluidity is deteriorated, so that it cannot be put to practical use. , But is not included in the scope of the present invention.

By curing the above-mentioned lightweight concrete for filling, the unit volume mass is 1,000.
It is possible to obtain a lightweight cured product in the range of 1,500 to 1,500 kg / m ³ .

[0019]

Embodiments of the present invention will be described with reference to [Table 1] to [Table 4].

[0020]

[Table 1]

[Table 1] is an experimental example showing the performance of cement paste depending on the different admixtures. As the admixture, a high-performance AE water reducing agent and a high-performance water reducing agent were mixed in the proportions shown in the same table. Then, two types, a tough type and a soft type, were prepared, and the flow value and the viscosity were respectively obtained and compared. As a result, the flow rate and the viscosity were both the same in the hard-stick type, but the flow value was the same in the soft-stick type, but the viscosity was lower when the high performance AE water reducing agent was used. . From this, it was found that the hard-viscosity type did not show a difference due to the difference in the admixture, but the soft-viscosity type had a low viscosity even though the mixing amount was low. This proves that it is a good lightweight concrete for filling.

[0022]

[Table 2]

[Table 2] and [Table 3] are experimental examples showing the relationship between fluidity and separation due to the difference in the admixture when foam beads are mixed. Among them, [Table 2] is cement, water, The respective compounding ratios of the admixture and the expanded beads are shown.

[0024]

[Table 3]

[Table 3] shows that the high-performance AE water-reducing agent used in the present invention and the conventional high-performance water-reducing agent were used as the admixture of [Table 2].
This is a comparison of the types prepared, and the fluidity, separation and compression density obtained respectively. As a result, in the tough type, the flowability was poor, there was no separation, and the compressive strengths were the same, so there was no difference between the two.
However, in the soft-viscous type, the fluidity is good and the separation was not in the high-performance AE water reducing agent, but it occurred in the high-performance water reducing agent, and the compressive strength was higher in the high-performance AE water reducing agent than in the high-performance water reducing agent. The result is also large. From this, it was found that the high-viscosity type water-reducing agent was superior in the soft-viscous type in terms of separation and compressive strength.
This proves that it is a good lightweight concrete for filling.

[0026]

[Table 4]

[Table 4] is an experimental example comparing the fluidity, separation and compressive strength of concrete when the same high-performance AE water reducing agent was used as a soft-viscosity type and the conditions of the foam beads were changed. . As is clear from this table, in the case of the same specific gravity (0.1 or 0.05), when the expanded beads have a particle size of 1.5 mm or less, the fluidity is less than that when the particle size is 2-3 mm. It was found that it was good, there was no separation, and the compressive strength was excellent. For reference, an experiment was carried out on a pulverized product having an average diameter of 1.5 mm or less and a specific gravity of 0.1. The fluidity was poor, but there was no separation, and the compression strength was 2 to 3 mm. It was found to be better than the one with a grain size of 1.5 mm but worse than the one with a grain size of 1.5 mm. From this, it was found that the foamed beads having a particle diameter of 1.5 mm or less were excellent.

[0028]

As is clear from the above description, the lightweight concrete for filling according to the present invention uses the high-performance AE water-reducing agent and therefore has a higher viscosity than the conventional high-performance water-reducing agent. Has the advantage that it is small, has high fluidity, does not cause separation, and has high compressive strength.

Further, by using the synthetic resin foam beads having an average particle diameter of 1.5 mm or less as the concrete fine aggregate, the measurement and the control of the water-cement ratio can be simplified, and the variation in the quality of the concrete can be reduced and the quality of the concrete can be reduced. You can get consistent concrete.

Further, unlike the conventional sand, since it is spherical, the water absorption rate is small, and the fluidity of the concrete is improved, so that the amount of water can be reduced accordingly, the neutralizing performance, the watertightness and the freezing. Melt resistance is improved. In addition, no separation occurs and the compressive strength is improved.

Furthermore, the specific gravity of concrete can be reduced and the weight can be reduced.

Further, when polystyrene expanded beads are used as the synthetic resin expanded beads, the strength of the concrete is further increased due to its properties and the cost is low.

Furthermore, the specific gravity of polystyrene foam beads is
When it is in the range of 0.2 to 0.05, it is suitable for pumping concrete in a fluidized state, the strength of hardened concrete is maintained, and deterioration of noncombustibility can be prevented.

In addition, when the water-cement ratio is 40% or less, a lightweight concrete for filling can be obtained in which the concrete quality such as compressive strength and dry shrinkage is further improved.

The light-weight cured product obtained by curing such lightweight concrete for filling has a unit volume mass of 1,000 to 1,
It is in the range of 500 Kg / m ³ , which is an advantage that it is greatly reduced compared to the conventional hardened concrete. Since the lightweight cured product of the present invention has the above-mentioned various characteristics, it is used as a concrete filling material for fireproof safes and metallic OA floors, fireproof covering material for pillars and beams, and lining material for civil engineering and construction panels. Applications include gap filling materials.

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display area C04B 24:22) Z 111: 40

Claims (5)

[Claims] 1. At least cement, water, high-performance AE
Average particle size of 0.1 to 1.5 mm as a water reducing agent and lightweight fine aggregate
A lightweight concrete for filling, which is characterized by using four kinds of mixed materials of synthetic resin foam beads in the range of. 2. The filling lightweight concrete according to claim 1, wherein the synthetic resin foam beads are polystyrene foam beads. 3. The average true specific gravity of polystyrene expanded beads is
The lightweight concrete for filling according to claim 2, which is in the range of 0.2 to 0.05. 4. The lightweight concrete for filling according to claim 1, wherein the water-cement ratio of the concrete is 40% or less. 5. A lightweight cured product having a unit volume mass in the range of 1,000 to 1,500 Kg / m ³ by using at least synthetic resin foam beads as one of the mixing materials.