JPS60141683A - Mortar injection treatment for lightweight foamed concrete - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] Conventionally, in a method for producing lightweight aerated concrete, 'i
After stirring the aerated concrete raw material slurry in a mixer and injecting it into the formwork, rough air bubbles may be mixed in, creating coarse cavities (about 3~/θ) on the surface and inside of the product. When the product was used as wall material, it had a significant appearance defect. In most cases, this product surface is painted, but in this case, it takes a lot of man-hours to repair the rough cavities, and even if the repair is done, the appearance is not good.
The current situation was that the number of incidents was increasing. The cause of this coarse cavity is the entrainment of air due to the occurrence of turbulent flow at locations where air exists in the path during injection shown in FIG. As a countermeasure to this problem, attempts have been made to make the flow during injection laminar or to create a structure that facilitates defoaming, but these efforts have not been very effective. For this reason, the present invention was developed based on the recognition that the only way to achieve complete defoaming was to perform forced defoaming after injection. It is known to forcibly remove air bubbles trapped in the mortar after pouring using a rod-shaped vibrator, but it is difficult to uniformly remove air bubbles from the mortar over the entire area of the mold using illegal methods. Furthermore, if an attempt is made to increase the uniformity, a large number of vibrators will be required, making it impractical to accommodate the equipment.

In particular, as shown in Figure 1 (a), 2) and (e), the vicinity of the rod-shaped vibrator in mortar 2 in Figure 2 4 cannot be avoided due to strong vibrations (at this time, the mortar in part 7 is already The main reason is that the bubbles start to bubble and the bubbles are destroyed) and that the defoaming effect changes depending on the distance from the vibrator.

The present invention overcomes the above drawbacks and provides a thixotropic mortar slurry with a relatively low viscosity (3θ0 to 9oθ0 centiboise as measured by a B-type viscometer) in which fine powder is dispersed, and which also contains a blowing agent. It has been found that forced defoaming can be carried out uniformly and effectively by vibrating the bottom plate of the form during partial foaming.

Traditionally, with heavy mortar, such as concrete mortar containing aggregates such as gravel, the slump value indicates that even if the mortar immediately after mixing is placed on a horizontal table, it will not flow until it becomes flat. When filling the formwork with such a highly viscous and hard mortar, as shown in Figure 1 (a), there are large gaps and gaps 10. To eliminate this, by applying vibration, the large and small bone phases in the concrete mortar composition move, and the mortar also moves to fill the space uniformly.

In other words, with this method, the fluidity of the mortar is extremely low,
It is difficult to uniformly inject the fluid into the molds I and 7, which is why vibration is applied. For this reason, even the table vibrating type 9 requires a greater amount of vibration than the present invention. In addition, the main purpose of these stone-based mortars was to uniformly fill the mortar, to improve the compactness, and especially to eliminate voids on the mold release surface.

On the other hand, in the case of mortar containing foamed Ha11 as in the present invention, the main purpose is not to improve the compatibility with the mold, improve the mold release surface, and make the mortar composition dense, but rather to The sole purpose is to defoam the air bubbles in the mortar. Figure 2 for lightweight aerated concrete (see below)
, (E), The part indicated by the dotted line in 9 is an example of a cutting location, and semi-hardened mortar blocks are cut into various sizes vertically, horizontally, and in various shapes with steel wires of θ, za~/σ. When cutting with a mortar, coarse traces of air bubbles of trapped air appear on the cut product surface, and as a countermeasure for this problem, the purpose of the invention is only to remove air trapped in the mortar. Furthermore, when pouring lightweight aerated concrete (containing a foaming agent), vibration of the bottom plate of the formwork was thought to be extremely difficult due to the following reasons. 7
The mortar already contains a foaming agent, and removing this will promote foaming in Part 7 and also cause foaming, resulting in uneven foaming, so it is difficult to do so, and it is considered that the father's method should not be used. Ta. 2. Most lightweight aerated concrete has an absolute dry specific gravity of about 0.5, so the strength of the block is weak when the mortar is semi-hardened, so when the block is transferred in a semi-hardened state, the bottom plate of the block formwork If the level twirls even slightly, the blocks will break or the blocks will be placed in one place.For this reason, the level accuracy of the bottom plate of lightweight aerated concrete forms is required to be more precise than that of concrete products such as ready-mixed concrete. The method of vibrating the frame bottom plate was thought to be extremely difficult. 3 The viscosity of mortar slurry is much lower than that of concrete products such as ready-mixed concrete, and mortar leakage from formwork is extremely disadvantageous.

Based on the above, in the present invention, we first adopted a method of vibrating the bottom plate of the formwork, which was previously unthinkable in lightweight cellular concrete, from the viewpoint of uniformly and completely removing air entrained in the mortar, which is the main purpose, and then the timing of vibration. As a result, we have found conditions in which the blowing agent is quickly carried out during a small amount of partial foaming during and after injection.

Next, a detailed explanation of the present invention The mortar slurry as used in the present invention is composed of sandstone, quicklime, cement, and stone that have been pulverized to 14 degrees by passing through a sieve with a sieve opening on a sieve mesh. A slurry is obtained by mixing koi and the like in a predetermined ratio as shown in the examples, and adding water at a ratio of 50 to 9θ relative to the solid content/0θ. In addition to these, the composition contains a fluidity improver, a curing accelerator/modifier, or a finely pulverized filler, as required.

In addition to the above slurry, a blowing agent that reacts with an alkali such as aluminum powder to generate hydrogen gas is added with a solid content of 1
0.07 to 0.70 part is added to 0θ.

As shown in Fig. 5, it is more preferable for the injection method to be devised to make the mortar flow laminar, but by implementing the present invention, the injection method is not particularly limited in relation to defoaming of trapped air bubbles. You don't have to. Next, regarding the formwork, it is as follows. The formwork dimensions can be used without any particular limitations as long as they can be used for lightweight aerated concrete products, but a formwork with a lower mortar injection height of θ to λθθ can be applied to a wider range and will prevent trapped air bubbles. This results in favorable results for defoaming.

(2) Vibrating the formwork bottom plate 1 (For H, the key points are as follows. ■) Making only the bottom plate move as uniformly as possible will impart uniform vibration to the mortar, i.e. It is also advantageous in terms of defoaming, and since the bottom plate 1 is usually the widest surface in contact with the mortar 2, it is most efficient to vibrate it in terms of the effect of vibration.

Also, from the point of view of not imparting unnecessary vibrations to the formwork, it is important point 7 to apply vibrations only to the bottom plate portion l of the formwork as much as possible.

In the present invention, as a method of applying vibration to the mortar slurry 2, in the case of a thick bottom plate made of steel with high rigidity, it is preferable to attach the vibrator 4 directly to the bottom plate 1 as shown in FIG. If the surface of the formwork bottom plate is thin, it is preferable to attach the vibrator 4 to the functional part of the bottom plate, which has a seven-piece structure with a framework to maintain the planar accuracy of the formwork bottom plate. In this case, it is preferable to the method of vibrating the bottom plate itself or a portion close to the bottom plate. Furthermore, as shown in FIG. 2, a vibrator may be brought into close contact with or attached to the upper surface of the mold, and vibrations may be transmitted through the bottom plate of the mold.

As shown in Fig. 2, when the formwork bottom plate 1 is made larger than the product mortar block, a vibrator can be attached or closely attached to the part 4 in Fig. 2 (B), and Vibration can be transmitted effectively.

As the vibration source, the most preferable method is to install or set a vibration motor with an eccentric on both sides and bring this slight vibration into close contact with the bottom plate of the formwork with a magnet, and adjust the frequency with a frequency converter. You can also do it. In this case, the capacity and number of motors may be selected and arranged so that the following vibration conditions are satisfied at the bottom plate of the formwork in each section when mortar is actually filled in the formwork.

The vibration conditions to be satisfied are that the average acceleration is θJIJ or more, the amplitude is θ, θ3 or more, and the vibration frequency is θθθ times/min or more. Among these, particularly preferable vibration conditions are as follows, which are the same as above. Average acceleration 7G~/θG vibration [1] θ, θ
, del/return, frequency jθθθ~/, 2θθθ'/l) M
It is preferable to suppress the zero-crossing and increase the vibration frequency from the viewpoint of defoaming effect and reducing the load on the formwork. In addition, when adding the maximum vibration load, if there is a risk of damage due to large scattering of mortar or large resonance of the entire formwork, the capacity of the vibrator may be slightly lowered.

Next, there are the following types of vibration sources that apply vibrations from the top of the formwork to both sides of the formwork bottom plate by manual operation each time a vibration operation is performed. These are usually called wall-type vibrators, and there are seven types of convenient vibrators. It has an output of about 22θW, a vibration frequency of 9θ0θ~/2θθθ times/minute, and an amplitude of about θ3. ) by bringing it into close contact with the bottom plate, through the formwork bottom plate,
Transmits vibrations to the mortar.

The vibrations applied to the bottom plate of the formwork may be vibrations in the horizontal direction as well as vertical movement of the bottom plate. As a main method of obtaining horizontal vibration, there is also a method of closely pressing the vibrator 4 against the side surface of the bottom plate portion 1 of the formwork.

The next time to apply vibration is as follows. The vibration may be started at any time as long as mortar is present on the bottom plate IF of the formwork. The timing at which the vibration ends varies depending on the height of the mortar from the bottom plate of the formwork to the two sides of the block, and the viscosity of the mortar, but as a rough guide from the appearance, gas is released from the top surface of the mortar 2 under vibration load due to degassing. It bubbles like a crater on the moon, but the vibrations end when most of the bubbles disappear. Next, the relationship between the amount of foaming and the vibration timing that can be achieved by the present invention is as follows.

First of all, the final foaming amount in the present invention is defined as the "filling height of the mortar slurry 2 immediately after pouring as shown in FIG. In the case of absolute dry specific gravity θ, jθ, the ratio of injection amount to final foaming amount is /θθ: Otsuj−2.
It is approximately θ.

In addition, after mixing the foaming agent and until the injection is completed, 7 parts of the foaming agent foams, but in the present invention, the foaming amount after this injection is:
Indicates when to apply vibration.

It usually takes 7 to 1 minutes to complete the injection after mixing the foaming agent, and if the foam is allowed to foam freely during this time, it will foam by 0.2 to 0.2 of the final foaming amount per 7 minutes, depending on the foaming agent. . In actual injection, the initial foam does not form, but due to the collapse of the bubbles during injection, the foam is injected with a slight amount of foam. In the present invention, after the injection is completed, it is necessary to apply vibration to within 3% of the final foamed stone (the amount of foaming confirmed in advance when foaming is performed without vibration after injection), and preferably It is within t%. The foaming agent in the mortar actually foams when pressed against the formwork. In the form bottom plate vibration method of the present invention, even if the 7-part foamed mortar bubbles during vibration, it is possible to obtain the specified absolute dry specific gravity by increasing the power of the foaming agent in advance. Moreover, the mortar specific gravity can be made uniform within the formwork.

When applying vibration after pouring all the mortar, 700 parts by weight of solid content, 3-0 to 0 parts by weight of mortar moisture, and 7 to j minutes of vibration under the vibration conditions described above is sufficient. be. Further, since the apparent viscosity of the mortar increases due to foaming of the foaming agent, the less foaming of the foaming agent there is, the lower the mortar viscosity becomes, which is preferable. Examples of viscosity changes due to foaming of mortar are shown in Table 1.

Table-1 Mortar viscosity is B type rotary meter rotor #330rp
m, the value at 0°C.

Next, the composition and viscosity of mortar and the effect of defoaming due to vibration are as follows.

The ease with which air trapped in the mortar can be defoamed using the form bottom plate vibration method of the present invention is related to mortar viscosity, and the relationship is shown in FIG. The horizontal axis is the viscosity of the mortar slurry immediately after mixing the foaming agent at θ° C. using rotor #3 of a B-type rotational viscometer and a rotor rotation speed of 3θ rpm, and the unit is centipoise. The vertical axis shows the air bubble inclusion coefficient, as shown in the dotted lines in Fig. 2 (F) or (/→), after pouring mortar into the formwork and pre-curing it, after removing the side plate, the upper surface of the mortar 2 is set to θ, The coefficient was calculated as follows for a surface cut with ♂Ω piano wire to make it a smooth surface.The air bubble inclusion coefficient refers to the air bubble diameter of 3 to less than 7 mm, The plate surface per /rrl is divided into two categories: less than 7 to 10, less than 7 to 10, and the surface of the plate per /rrl is counted and multiplied by /Otsu, 3Otsu, Otog, and /θθ, respectively, and the sum is calculated. The black circle in Figure 3 shows the relationship between the mortar viscosity and the sudden air inclusion coefficient without vibration treatment. 3
Large bubbles at θθθ were clearly present, and the result was at a level that could not be put to practical use. On the other hand, white circles are those that have been subjected to vibration, and can be significantly improved to a state in which the air bubble inclusion coefficient is reduced by % or zero. The mortar slurry shown in the first figure is based on the mortar composition described in Examples, and only the water content is changed in the mortar composition. The relationship between water content and viscosity is as shown in Figure 2. In the mortar of the present invention, the mortar slurry has a structural viscosity called thixotropy ('f kit lobby), and it is difficult to simply express mortar viscosity, so it is necessary to clarify the measurement conditions. be. A mortar slurry of the present invention having thixotropy exhibits different values depending on the rotational speed of /2 rpm, 30 rpm, and Qrpm in FIG. 7, and the viscosity J1. That is, the higher the rotational speed, the more the structural viscosity is destroyed and the viscosity becomes lower. The mortar viscosity in the present invention is 30
θ~W θ0 θ centipoise refers to the low to medium viscosity range as follows. B type viscometer rotor & 3, 30
3θθθ~riθθ0 centipoise indicates the measured value at rotor 3/;l rpm. Father, the measured temperature is 90°C. Furthermore, the mortar viscosity 3θθ to 9θθθ centiboise region as used in the present invention refers to a water ratio of 9θ to aS weight parts of water to solid content of 10θ weight parts.

The mortar viscosity shown in Fig. 14 is correlated with the mortar viscosity shown by the 3θrpm line shown in Fig. 7 in relation to mortar moisture.

The lower the viscosity of mortar, the faster the rate of rise of trapped air bubbles and the easier defoaming.
Vibration has the effect of destroying large bubbles, and small bubbles coalesce with each other, accelerating the rising and defoaming speed of the bubbles. Vibrations greatly reduce the number of trapped air bubbles in mortar. be able to.

When the mortar viscosity shown in Fig. 3 reaches 2θθθ centipoise, the air bubble mixing coefficient can be set to zero or less than /part/θ0 as shown in Fig. 3 under the following vibration conditions. That is, with mortar in the formwork, the average acceleration of the bottom plate of the formwork is 7G, -J-G vibration frequency SOOθ~♂0θ0v
PM, vibration time 7 to 2 minutes. When the mortar viscosity shown in Figure 3 is λθθθ~jθθ0 centipoise, the air bubble mixing coefficient is 70 as shown in Figure 3 under the following vibration conditions.
It can be less than 0. That is, with mortar in the formwork, the average acceleration of the bottom plate of the formwork is 30 to 70G, the vibration frequency is 6000VPM ~/, the vibration time is 2000VPMS / ~
That's a lot. If no vibration is applied, the bubbles will vary greatly depending on the method of injection (particularly as the mortar viscosity increases). On the other hand, by applying vibration, it is possible to obtain a uniformly bubbled surface, and the variation in the air bubble mixing coefficient shown in the figure is also greatly reduced.

Next, an explanation will be given based on an example.

Example/Portland cement 3θ weight part, quicklime fine powder (l
Parts by weight of ♂ parts by weight, fine sand stone powder with a pass of 9 degrees or more, and the same composition as above, solid content/1 part by weight of recovered waste mortar and 70 parts by weight of water. 10 parts were mixed in a mixer 14, and then fine aluminum powders θ and θ7 as foaming agents were added and stirred for 30 seconds. At this time, the mortar viscosity was measured using a 13-type rotational viscometer using roller #3, the rotation speed was 3θ rpm, the slurry liquid temperature was 0°C, and the temperature was 0°C.
It was centiboise. In addition, the foaming properties of the kt used at this time were 70% compared to the final foaming amount at 3 minutes after injection.
It foams at a rate of 20 degrees in 5 minutes and 20 degrees in 70 minutes, and has the characteristic of foaming at a rate of 2 degrees per 7 minutes after At mixing and until it is added. Immediately after mixing the kl, as shown in Figures 3 and 5, length x width/, width x 1.
The mold was poured to a depth of 70 strokes into a mold 1.7 having internal dimensions of 0.2 m.

It took 7 minutes from the start of the injection to the completion. Thereafter, the bottom plate I of the mold was vibrated for 7 minutes as shown in FIG.

Prior to the injection, seven iron rib cages θKg made of anti-rust treatment were set so that they would not shift even when subjected to vibrations.

Next, the vibration conditions are as follows. Frequency≦3-0θVP
M, average acceleration [uG. However, this acceleration is an actual value measured on the bottom plate of the formwork containing mortar. After the vibratory degassing was completed, the mortar had numerous traces of air bubbles, indicating that degassing had occurred. After this mortar block is hardened to a mortar hardness that allows the side plates to be removed, it is cut with piano wires θ and ♂ at positions 1 and 2 j ttrm from the bottom plate 1 of the formwork so that the surface is smooth and smooth. When the air entrainment coefficient was measured, it was zero, there were no air bubbles of 3 or more, and the appearance was extremely good. Also, at this time, the block height before cutting is /, ll''
Evening lol I got teary. Furthermore, the variation in specific gravity within the same formwork was measured at two equally spaced locations, and was found to be extremely good in the soil section, with no heavy areas observed. Moreover, the absolute dry specific gravity of the unreinforced portion of the obtained plate was θ, SO.

Example 2 Same solid content composition as Example/, solid content/θθit
The mixture was mixed with a mixer 14, and then 0.07 parts of fine aluminum powder as a foaming agent was added and stirred for 30 seconds. At this time, the mortar viscosity was measured with a B-type rotational viscometer #30-ter, 3θrpln, and the liquid temperature was θ0°C. Immediately thereafter, as shown in Figure 3, length j, 1 m
The mixture was poured into a mold 1.7 having an inner dimension of n to a depth of /θ. It took one minute from the start of the injection to the completion. At used
The foaming characteristics of the final foamed electricity are 75% at 3 minutes +2.5 minutes and 37% at 10 minutes after injection, and the foaming rate is 37% at 7 minutes until the KT mixing stage is added. / It has the characteristic of foaming. Thereafter, the formwork bottom plate 1 was vibrated for 2 minutes as shown in FIG. The vibration conditions at this time are as follows. The vibration frequency was 7.2θ0■PM, and the average acceleration was jG. However, this acceleration value is an actual value measured on the formwork 1 and the civil board 1 containing the mortar 2. After the vibratory defoaming was completed, the sample was horizontally cut in the same manner as in Example 1, and the air entrainment coefficient on that surface was measured and found to be only 9. A plate obtained by molding in the same manner as above without applying vibration had an air inclusion coefficient of 2/W θ. Moreover, the absolute dry specific gravity of the unreinforced portion of the obtained plate was θ, j.

As described above, according to the present invention, most of the air bubbles trapped inside the lightweight foam cock mortar can be defoamed, and a plate with a good appearance without uneven air bubbles on the product surface can be obtained.

[Brief explanation of the drawing]

Figures 7(a) and 7(b) are cross-sectional views of the conventional method of compaction using heavy mortar such as concrete mortar. Figure 2 (a), (b), ()→, ni), (e) and (
(a) to (f) is a cross-sectional view of the situation from the completion of pouring the foamed concrete slurry to the completion of foaming in the method using a foaming agent. ) to), (e) is when the mortar part is spot treated with a rod-shaped vibrator, (a) to (b)
, and 9 are cases in which the vibration method of the bottom plate of the formwork according to the present invention was used. Each shows the state of defoaming and small bubble formation. FIG. 3 is a cross-sectional view of the situation in which vibration is applied from the bottom of the bottom plate of the formwork to defoam the mortar. Figure 3 is a plan view of the situation in which vibration is applied from the top of the bottom plate of the formwork to defoam the mortar (A).
and a cross-sectional view (b). FIG. 5 is a perspective view showing a situation in which mortar is injected into the formwork and defoaming treatment is performed. The second figure is a graph showing the relationship between the mortar viscosity and the air bubble inclusion coefficient, which shows the effect of defoaming according to the present invention. It is. FIG. 7 is a correlation diagram between mortar moisture and mortar viscosity. In the drawing, l is the bottom plate of the formwork, 2 is the mortar slurry,
3 is a reinforcing reinforcing bar, 4 is a vibrator, 5 is a damping material part that absorbs vibrations, 6 is a formwork holding part, 7 is a formwork side plate, 8 is a formwork truck part,
9 is a vibration table, 1o is a gap, 11 is an entrained air bubble, 12 is a foaming agent D, J: 7. J Koki fa, 13
is an injection nozzle, 14 is a mortar mixer, and I5 is an injection port. Figure 1 (a) (b) Figure 2

Claims (1)

[Claims] When pouring a light foam concrete mortar slurry made by adding water into a slurry using finely pulverized powder raw materials and further adding a foaming agent into the formwork, the mortar slurry has a viscosity of 300 to 90 θθ centipoise. After the injection is completed, the foaming agent vibrates the bottom plate of the form during partial foaming within 3θ relative to the final foaming point, and the vibration gives vibration to the mortar slurry, defoaming the trapped air bubbles in the mortar. Mortar injection treatment method for lightweight aerated concrete using a foaming agent characterized by