JP4551159B2 - Mortar or concrete spraying method - Google Patents

Description

  The present invention relates to a method for spraying mortar or concrete.

The present applicant, when spraying mortar material or concrete material on a formwork pre-formed on a high slope, to form a grid-like lawwork, in order to efficiently perform the high place spraying construction, As shown in Patent Documents 1 and 2 below, a separate pumping method for separately pumping cement milk and aggregate constituting mortar material or concrete material is proposed.
JP 2001-248164 A Furthermore, in the separate pressure feeding method spraying method, the present applicant uses the water content [water / (aggregate) of water constituting the mortar or concrete material from the aggregate pressure feeder side. + Water) × 100)] is added to the aggregate so as to be 5 to 10 wt%, and the remaining water is added to, for example, cement to form cement milk, whereby the aggregate and cement milk are uniformly mixed A mortar or concrete spraying method has been proposed in which mortar or concrete spraying with high strength can be performed economically and efficiently (see Japanese Patent Application No. 2002-142508 and drawings).

  However, in order to increase the transportability of the aggregate, the amount of water contained in the cement milk is reduced, so that the concentration of the cement milk is increased, and thus the transportability of the cement milk is decreased. It is necessary to use a powerful squeeze pump as the pump for pumping, and when spraying high-strength mortar or concrete, it is possible to improve the transportability of sand, but keep the transportability of cement milk high. There is a problem that you can not.

And in the separate pumping method spraying method (refer to Japanese Patent Application No. 2002-142508 specification and drawings) in which the above-described cement milk and aggregate are separately pumped, for example, sand is pumped as aggregate. In the case of absolutely dry sand or sand to which water content is added to 8 wt%, for example (hereinafter referred to as 8 wt% water), the hose can be pumped without clogging, and the water content is 5 wt%. It has been found that the front and rear sands tend to clog the hose.
Therefore, the present invention can reduce the concentration of cement milk if, for example, sand having a moisture content of around 5 wt% can be pumped in the low moisture state as it is, and can maintain high transportability of both cement milk and sand. This is based on the technical idea that strength is possible. Below, the experimental result regarding the pumpability of sand is demonstrated.

The present applicants first performed the following preliminary experiment.
Preliminary experiment
〔Evaluation methods〕
A method for simply evaluating the clogging of sand was investigated.
The pipes made of vinyl chloride having different lengths and diameters were naturally filled with sand, and clogging was evaluated from the presence or absence of falling when the pipe was lifted.
Pipes having a diameter (inner diameter) of 20, 30, 40, 50 mm and lengths of 150, 200, 250, 300, 350 mm were naturally filled with sand having a moisture content of 0 to 10 wt%, and the presence or absence of falling was measured. As a result, in a sand drop experiment from a pipe having a diameter (inner diameter) of 30 mm and a length of 200 mm, it was found that the sand does not fall when the water content is 4 to 7 wt%. In addition, when a pipe having a diameter (inner diameter) of 30 mm and a length of 150 mm was used, all the sand having a water content of 0 to 10 wt% was dropped. In addition, when a pipe having a diameter (inner diameter) of 30 mm and a length of 250 mm or more was used, it was found that except for absolutely dry sand (sand having a moisture content of 0 wt%), almost no fall occurred. It was also found that when the pipe diameter (inner diameter) was increased to 40, 50 mm, all the sand with a moisture content of 0-10 wt% dropped.
From these facts, it was considered that clogging of sand can be evaluated by the presence or absence of falling when a pipe having a diameter (inner diameter) of 30 mm and a length of 200 mm is naturally filled. In other words, sand with a moisture content of 3 wt% or less slips down because the frictional resistance with the pipe wall of the pipe is small. However, with sand with a moisture content of 4-7 wt%, the sand forms a bridge and the frictional resistance is reduced by moderate wetting of the pipe wall. It will not fall high. When the sand has a water content of 8 wt% or more, it is considered that excessive water becomes a lubricant, reducing the frictional resistance between the pipe wall and the sand.
[Hygroscopic agent]
In order to reduce the apparent water content of sand, the addition of powders such as ultrafine powder with a large specific surface area and baked gypsum that incorporates crystal water was considered.
Therefore, 1 to 10% of silica ultrafine powder (white carbon), calcined gypsum, cement and the like was added to the weight of the sand. If any powder is left for about half a day, the apparent moisture is reduced and it becomes smooth. However, there remains a problem that the change is little for a while after mixing and kneading, and it takes time until the construction.
Considering the cost, there is a method of using waste such as fly ash and gypsum, but it is considered that it takes time after adding and mixing.

Next, the applicants conducted the following experiment.
Experiment
In order to change the sand state quickly, addition of a surfactant was considered. Therefore, the addition of powdery surfactants and liquid surfactants such as physics and chemistry equipment cleaners was tried. Similarly, a pumpability improver not containing a surfactant as a main component was also examined.
Examples of the main component used in the powdery surfactant include sodium oleate, and examples of the main component used in the liquid surfactant include sodium dodecylbenzenesulfonate and polyoxyethylene lauryl ether sulfate. Polyoxyethylene polyoxypropylene butyl ether can be mentioned, but here, a powdery surfactant containing sodium oleate as a main component was used. Moreover, what has polyoxyethylene lauryl ether sulfate ester as a main component was used as a liquid surfactant.
In the test method, an additive was added to 500 g of 5 wt% sand obtained by adding water to absolutely dry sand, and the packing density after kneading and the presence or absence of dropping from the pipe were evaluated.
The filling density was measured by measuring the capacity after naturally filling 250 ml of sand into a 250 ml graduated cylinder and applying vibrations of 250 / min and 310 / min with a vibrator.

Experimental Results FIG. 2 shows the relationship between sand, moisture content and filling.
From FIG. 2, it can be seen that the packing density decreases in the region where the amount of water is small, and further increases with the amount of water. Further, FIG. 2 shows that the packing density when vigorous vibration (310 / min) is applied is 4 to 7 wt% of moisture that is easily clogged, and is low. Although the direct relationship with this result is unknown, it correlates with the substance to some extent.
Tables 1, 2 and 3 below show the relationship between each additive, filling density and dropping.

ここで、
Ｉ：２５０ｍｌメスシリンダ自然充填
ＩＩ：加振
ＩＩＩ：加振
×：落下せず
△：５０％落下
□：７０％落下
○：すべて落下

here,
I: 250 ml measuring cylinder natural filling II: Vibration III: Vibration ×: No drop △: 50% drop □: 70% drop ○: All fall

ここで、
Ｉ：２５０ｍｌメスシリンダ自然充填
ＩＩ：加振
ＩＩＩ：加振
×：落下せず
△：５０％落下
□：７０％落下
○：すべて落下

here,
I: 250 ml measuring cylinder natural filling II: Vibration III: Vibration ×: No drop △: 50% drop □: 70% drop ○: All fall

ここで、
Ｉ：２５０ｍｌメスシリンダ自然充填
ＩＩ：加振
ＩＩＩ：加振
×：落下せず
△：５０％落下
□：７０％落下
○：すべて落下

here,
I: 250 ml measuring cylinder natural filling II: Vibration III: Vibration ×: No drop △: 50% drop □: 70% drop ○: All fall

The powdery surfactant (Table 1) and the liquid surfactant (Table 2) were in a dry state although they were wet after addition kneading. However, on the contrary, the pumpability improver (Table 3) was more moist. Dropping was effective with the powdery surfactant and the liquid surfactant, and even when the amount of addition was increased, a pipe having a length of 250 mm could be dropped. On the other hand, the pumpability improver does not drop at all, and the packing density (density II in Table 3) when applied with a small amount of vibration is the powdered surfactant (density II in Table 1) and the liquid surfactant ( The density was lower than that in the case of density II) in Table 2 and was different from the powder characteristics.
In Tables 1 to 3, density I indicates the packing density when 250 ml of graduated cylinder is naturally filled with sand up to 250 ml, and density II indicates that the 250 ml graduated cylinder is naturally filled with sand up to 250 ml. The packing density when 250 / min vibration is given by a vibrator is shown. Density III is when the 250 ml graduated cylinder is naturally filled with sand up to 250 ml and the vibrator is given 310 / min vibration. The packing density is shown.

  The present invention has been made based on such knowledge, and is capable of maintaining high transportability of both cement milk and aggregate and capable of efficiently performing high strength mortar or concrete spraying. It aims to provide a concrete spraying method.

To achieve the above object, according to the mortar or concrete spraying method of the present invention , the cement-free aggregate supplied from the aggregate pump and the cement milk supplied from the cement milk supply means are separately provided. In a mortar or concrete spraying method in which mortar material or concrete material is obtained by pumping and mixing to obtain mortar material or concrete material, a part of water constituting the mortar material or concrete material is In addition to being added to the aggregate supplied from the aggregate pumping machine, a surfactant is added to the aggregate.
As the main component of the surfactant used in the present invention, higher fatty acid salts (salts represent salts of alkali metals, alkaline earth metals, alkanolamines, etc., the same shall apply hereinafter), alkylbenzene sulfonates, polyoxyethylene alkyls An ether sulfate ester salt, polyoxyalkylene alkyl ether, resin acid salt, higher alcohol sulfate ester salt selected from one or two or more types can be mentioned, specifically, oleic acid sodium salt, It is preferable to use one or two or more kinds selected from sodium dodecylbenzenesulfonate, polyoxyethylene lauryl ether sulfate, polyoxyethylene polyoxypropylene butyl ether, for example, the polyoxyethylene Polyoxypropylene butyl ether It is more preferable to use a surfactant as a main component ether and the sodium dodecylbenzenesulfonate.
Moreover, in this invention, it is preferable to add surfactant in the ratio of 0.01-0.20 weight part with respect to 100 weight part of aggregates, and it is added in the ratio of 0.07-0.13 weight part. It is more preferable in terms of stability of the aggregate conveying ability and economy.
This is because if the addition ratio of the surfactant is smaller than 0.01 parts by weight, the transportability of the aggregate cannot be sufficiently improved and a desired effect cannot be obtained.
If the addition ratio of the surfactant is greater than 0.20 parts by weight,
(1) While the amount of air mixed into the mortar or concrete becomes excessive and the strength of the resulting cured product is reduced (decrease in mortar or concrete quality),
(2) This is because the economy becomes worse.

  According to the present invention, in the spraying method in which cement milk and aggregate constituting mortar material or concrete material are separately pumped, the aggregate in which a part of water constituting the mortar material or concrete material is supplied from the aggregate pump Since the surfactant is added to the aggregate to which a part of the water has been added, the transportability of both cement milk and aggregate can be kept high. In addition, there is an effect that it is possible to provide a mortar or concrete spraying method that can efficiently spray mortar or concrete with high strength.

  Embodiments of the present invention will be described below. FIG. 1 shows a mortar material obtained by mixing sand and water as aggregates supplied from an aggregate feeder and cement milk supplied from cement milk supply means (usually the weight ratio is cement 1). : Sand 4: Water 0.6) The formation state of the frame 2 by spraying 1 and the greening protection state of the slope N by spraying the vegetation base 3 are shown.

  Specifically, a net 4 such as a wire mesh is stretched on the slope N, and reinforcing bars 5 are arranged on the net 4 in a lattice shape to form a normal frame spraying portion. While the curing sheet 6 is disposed, the mortar material 1 is sprayed so as to cover the grid-like reinforcing bars 5 to form the grid-like method frame 2, and then the curing sheet 6 is peeled off, and plant seeds and fertilizer are applied. The contained vegetation base 3 is sprayed into the frame 2 to protect the slope N from greening.

  In this embodiment, mortar material in which cement, sand as fine aggregate, and water are mixed as spray material will be described, but the present invention is cement, sand as fine aggregate, It goes without saying that the present invention can also be applied to concrete materials in which gravel, gravel, crushed stone, and the like as coarse aggregates and water are mixed.

  The mortar material 1 spraying device (hereinafter referred to as mortar spraying device) includes an aggregate pump 9 for supplying sand 8 and water 12a as fine aggregates, and an air compressor 10 connected to the aggregate pump 9. And a pump for pressure feeding (for example, a piston type pump and a squeeze type pump) 14 as a cement milk supply means for supplying cement milk 13 obtained by mixing cement 11 and water 12b, and the pressure pumped through the hose 15. It is obtained by mixing the sand 8, water 12 a, and the cement milk 13 (11, 12 b) pumped through the hose 16, and mixing with a portable mixing device 17 as mixing means for discharging the mortar material 1. The mortar material spray nozzle 20 for spraying the mortar material 1 is mainly used.

  Furthermore, the mortar spraying device has a hose 19 for feeding mortar material connected to a mortar discharge port 18 of the portable mixing device 17, and the mortar material spraying nozzle 20 is provided at the tip of the hose 19. ing. The hose 15 for pumping the sand 8 and the water 12a is a connecting hose having a length of about 400 m at the maximum, and the connecting hose 15 is connected to a number of short hoses of about 20 m. Further, the sand 8 and the water 12a are discharged at a predetermined discharge amount from the discharge port 9a of the aggregate pump 9 by the compressed air supplied from the air compressor 10.

  In the present invention, a part 12a of water 12a, 12b constituting the mortar material 1 is added to the sand 8 as fine aggregate supplied from the aggregate pump 9 and the part 12a of the water is added. A surfactant (for example, a material mainly composed of the above-mentioned polyoxyethylene polyoxypropylene butyl ether and sodium dodecylbenzenesulfonate) 21 is added to the sand 8. In this embodiment, a surfactant mainly composed of polyoxyethylene polyoxypropylene butyl ether and sodium dodecylbenzenesulfonate is added at a ratio of 0.10 parts by weight with respect to 100 parts by weight of the aggregate.

  The supply amount of the cement milk 13 (11, 12b) pumped by the pump 14 is set and changed by a discharge amount gauge provided in the pump 14, and is pumped through the hose 15 measured in advance or in real time. The mixing ratio of the sand 8 and water 12a to the cement milk 13 (11, 12b) is adjusted by adjusting the discharge amount of the cement milk 13 (11, 12b) by the pump 14 according to the pumping amount of the sand 8 and water 12a. Can be controlled arbitrarily.

As the mortar material 1 obtained in the present invention,
Cement 11: Sand 8: Water 12a, 12b = 1: 4: The thing with the compounding ratio (weight ratio) of 0.45-0.6 is preferable.
The specific blending amount of the mortar material 1 is, for example, the total amount of water 12a and 12b is added to 22.5 to 30 liters of (C) with respect to 50 kg of cement 11 (A) and 200 kg of sand 8 (B) per batch.

  In the present invention, among the water 12a and 12b constituting the mortar material 1, the water 12a from the aggregate pressure feeder 9 side is sand 8 so that the moisture content is 4 to 7 wt%, preferably 5 to 6 wt%. And the remaining water 12b is added to the cement 11. In this case, it is preferable that the water 12b added to the cement 11 has a weight ratio of about 50 to 55% with respect to the cement 11. At the same time, in the present invention, the surfactant 21 is added to the sand 8.

Thus, since the surfactant 21 is added to the sand 8, the conveyance resistance of the sand 8 containing the water 12 a is reduced, so that the conveyance performance equivalent to that of the sand 8 having a moisture content of 7 and 8 wt% is maintained. However, the amount of water 12a added to the sand 8 can be reduced as compared with the prior art, and the amount of water is added to the cement milk 13 accordingly, so that the concentration of the cement milk 13 can be lowered. Therefore, the transportability of the cement milk 13 can be improved.
That is, even if the water content ratio of the sand 8 is lowered by about 2.0 wt% compared to the conventional method, the transport resistance of the sand 8 is reduced by the addition of the surfactant 21, so that the transportability of both the sand 8 and the cement milk 13 is improved. It can be kept high.
Further, from another viewpoint, when the concentration of the cement milk 13 is set equal to that of the conventional method, the water (W) 12a and 12b constituting the mortar material 1 and the cement are reduced by reducing the water 12a added to the sand 8. (C) Since the ratio (W / C) of 11 can be kept low, this also leads to providing a mortar material 1 of higher quality and strength.

  In this embodiment, as a specific example, a case where a surfactant mainly composed of polyoxyethylene polyoxypropylene butyl ether and sodium dodecylbenzenesulfonate is used is shown, but the present invention is not limited to this. As specific examples of the main component of the surfactant, one or two selected from sodium oleate, sodium dodecylbenzenesulfonate, polyoxyethylene lauryl ether sulfate, polyoxyethylene polyoxypropylene butyl ether More than one species may be used, and more generally, as a main component of the surfactant used in the present invention, higher fatty acid salts, alkylbenzene sulfonates, polyoxyethylene alkyl ether sulfates, polyoxy Alkylene alkyl ether Resinates can be applied which consists of one or more selected from among higher alcohol sulfuric acid ester salt. In this embodiment, a surfactant mainly composed of polyoxyethylene polyoxypropylene butyl ether and sodium dodecylbenzenesulfonate is used, and polyoxyethylene polyoxypropylene butyl ether is used with respect to 100 parts by weight of the aggregate. And a surfactant mainly composed of sodium dodecylbenzenesulfonate at a ratio of 0.10 parts by weight, the ratio of the surfactant to 100 parts by weight of the aggregate is mainly used. It can be appropriately set within the range of 0.01 to 0.20 parts by weight depending on the components.

  Moreover, although the legal frame was taken up as embodiment of the mortar or concrete spraying method of this invention, it is applicable also to the slope protection construction method by mortar or concrete spraying other than a legal frame. In addition to the slope protection method, any method that sprays mortar or concrete is widely applicable.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. It is a figure which shows the sand in the said embodiment, the moisture content, and the relationship of filling.

DESCRIPTION OF SYMBOLS 1 Mortar material 8 Sand 9 Aggregate pump 12a, 12b Water which comprises mortar material 12a Part of water 13 Cement milk 14 Cement milk supply means 21 Surfactant

Claims (4)

Aggregate containing no cement and cement milk supplied from the cement milk supply means supplied from the aggregate pumping machine are separately pumped and mixed to obtain a mortar material or concrete material, and the mortar material Or, in the mortar or concrete spraying method for spraying concrete material, a part of water constituting the mortar material or concrete material is added to the aggregate supplied from the aggregate pump, and the aggregate A method of spraying mortar or concrete, comprising adding a surfactant to the mortar. The mortar or concrete spraying method according to claim 1, wherein a surfactant is added at a ratio of 0.01 to 0.20 parts by weight with respect to 100 parts by weight of the aggregate. The surfactant is one or more selected from higher fatty acid salts, alkylbenzene sulfonates, polyoxyethylene alkyl ether sulfates, polyoxyalkylene alkyl ethers, resinates, and higher alcohol sulfates. The mortar or concrete spraying method according to claim 1 or 2, characterized by comprising: The surfactant comprises one or more selected from sodium oleate, sodium dodecylbenzenesulfonate, polyoxyethylene lauryl ether sulfate, and polyoxyethylene polyoxypropylene butyl ether. The mortar or concrete spraying method according to any one of claims 1 to 3.

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