JP5754007B2 - Mortar structure forming method - Google Patents

Description

  The present invention relates to a mortar structure forming method used for forming a frame, for example.

  In general, a mortar composition is used in which the volume ratio of cement to aggregate is 1: 3 to 1: 4 in order to develop necessary strength in the mortar to be formed.

  However, cement is a limited resource, and it is desired to reduce the amount of cement used in the mortar composition as much as possible from the viewpoint of environmental problems.

  As for aggregates, particularly in the field of fine aggregates used for mortars, there is a search for fine aggregates that can be stably supplied and that can replace high-quality sand that is becoming difficult to collect. Among them, the use of lime crushed sand (crushed limestone that has been adjusted to sand) as a fine aggregate has been studied, but it has become widespread due to poor workability and high costs. Not in.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for forming a mortar structure that can save resources and reduce costs of cement and has excellent workability.

In order to achieve the above-mentioned object, a mortar structure forming method according to the present invention is a mortar structure forming method in which a mortar is pumped using a pressure pump and placed on a construction target surface. ˜22 parts by weight cement, crushed lime as 70 to 83 parts by weight of fine aggregate, and 3 to 10 weights having a particle size distribution with frequency peaks in at least two places of 5 to 20 μm and 80 to 180 μm Part of the limestone fine powder, the total amount is 100 parts by weight ,
The limestone fine powder used is prepared by adding water to a mortar composition containing 25% or more of fine powder having a particle size of 5 to 20 μm and 15% or more of fine powder having a particle size of 80 to 180 μm ( Claim 1).

  In the mortar structure forming method, air may be joined to the mortar to be pumped and sprayed from a spray nozzle to a surface to be constructed (Claim 2).

According to the first and second aspects of the invention, it is possible to save resources and reduce the cost of cement, and to obtain a mortar structure forming method excellent in workability.

That is, in the present invention, as the mortar, 14 to 22 parts by weight of cement, 70 to 83 parts by weight of fine lime sand and 3 to 10 parts by weight of limestone fine powder in total 100 weights As a result, it becomes easier to reduce the blending ratio of the cement and, hence, the amount of use thereof, as compared with the conventional mortar composition, which contributes to resource saving and cost reduction.

Moreover, when the blending ratio of the cement is lowered in the conventional mortar composition, the strength of the mortar is lowered. However, when the mortar composition of the present invention is used, it is formed while reducing the amount of cement used as described above. The strength of the mortar can be increased and a crack prevention effect is also imparted. The mechanism is that fine limestone powder with a small particle size (5 to 20 μm) improves the solidity of the mortar by entering between the lime crushed sand particles and the cement particles, and further, the particle size is large ( 80 to 180 μm). This is thought to be because the fine limestone powder maintains an appropriate distance between the crushed lime sand particles, and the cement particles are uniformly dispersed to assist the complete coating of the cement on the crushed lime sand.

  In addition, if the mixing ratio of cement is simply lowered in the conventional mortar composition, the (ball) bearing function for smoothly transporting the fine aggregate that the cement bears will be insufficient, and the fluidity of the mortar and thus the workability will decrease. Will end up. However, in the mortar composition of the present invention, the mixing ratio of the cement is not simply lowered, but the limestone fine powder having the same particle size as the cement particles and the particle size larger than the cement particles and smaller than the crushed sand particles. The blending with the fine powder of limestone has a bearing function and a mortar fluidity that are impaired by the decrease in cement, and further enhances the fluidity of the mortar.

  In carrying out the mortar structure forming method of the present invention, in addition to the mortar composition and water, a water reducing agent or fiber may be added and mixed (kneaded) as necessary. In addition, since the flowability of mortar can be improved, the required amount of expensive high-performance water reducing agent, which was indispensable when using conventional mortar compositions, is reduced. .

  In general, an excessive or too small amount of water added to the mortar composition prevents the formation of a good quality mortar, but the mortar composition of the present invention contains crushed lime sand having a property of not absorbing water as a fine aggregate. Compared to conventional blends that use water-absorbing sand as a fine aggregate, it is much easier to keep the amount of water that is not absorbed by the fine aggregate (outside the fine aggregate) constant. It helps to stabilize the quality of the mortar that is formed, and to simplify the production of high-quality mortar.

  Moreover, as described above, since the fine aggregate contained in the mortar composition of the present invention is crushed lime sand having no water absorption, the amount of water added when forming the mortar is reduced as compared with the conventional blending. In this respect, the present invention contributes to resource saving (water saving), and even when the amount of water added is reduced, the limestone fine powder that prevents the separation of water retains an appropriate amount of water as a mortar. Can be made.

  In addition, if an appropriate amount of water is added to the mortar composition of the present invention, the separation of water can be prevented by the limestone fine powder, and furthermore, the mortar has a good hardness and adhesion, so that it is sprayed onto the construction target surface. It is possible to reduce and prevent rebound loss (dispersion loss due to rebound on the construction target surface) and runoff (flowing down from the construction target surface) after spraying.

  Moreover, since the mortar composition of this invention uses the crushed lime sand which can be stably supplied in various places throughout the country as a fine aggregate, the spraying construction of this invention can be implemented suitably all over the country.

It is a whole structure explanatory view showing roughly the mortar structure formation method concerning a 1st embodiment of the present invention. It is a graph which shows the result of the particle size distribution measurement performed about the limestone fine powder mix | blended with the said mortar composition. It is whole structure explanatory drawing which shows roughly the mortar structure formation method which concerns on the 2nd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  A mortar structure forming method according to the first embodiment of the present invention (hereinafter abbreviated as a forming method) is prepared from a pressure pump (for example, a piston pump or a squeeze pump) 1 as shown in FIG. The mortar 4 which is a mixture of the mortar composition 2 and the water 3 supplied in a wet state is pumped to the slope N (an example of a construction target face) to form the slope frame 5.

  Specifically, a net 6 such as a wire mesh is stretched on the slope N, and reinforcing frame 7 is arranged on the net 6 in a lattice shape to form a method frame spraying portion. While the curing sheet 8 is disposed, the mortar 4 is supplied so as to cover the grid-like reinforcing bars 7 to form the grid-like frame 5, and then the curing sheet 8 is peeled off and the plant seeds and fertilizer are included. The vegetation base 9 is sprayed into the frame of the frame 5 to protect the greening of the slope N.

  In FIG. 1, reference numeral 10 denotes a spray nozzle, which is provided on the downstream side of a pipe (hose) 11 connected to the pumping pump 1.

  And the mortar composition 2 is 14 to 22 parts by weight of cement, 70 to 83 parts by weight of lime crushed sand as fine aggregate, and 3 to 10 parts by weight of limestone fine powder in a total of 100 parts by weight. Including to be.

  Here, as the cement, for example, portland cement such as ordinary portland cement, moderately hot portland cement, low heat portland cement, early-strength portland cement, mixed cement, and the like can be used.

  As said lime crushed sand, what has an average particle diameter (average particle diameter) of 0.6-1.2 mm can be used, for example, The lime crushed sand used by this embodiment is the aggregate based on JISA1102. As a result of the sieving test, the results shown in Table 1 (coarse grain ratio 2.68) were obtained.

As said limestone fine powder, the particle size which has a frequency peak in at least two places of 5-20 micrometers (particle size comparable as a cement particle) and 80-180 micrometers (a particle size larger than a cement particle and smaller than a lime crushed sand particle ). It has a distribution comprising a fine powder of particle size of 5 to 20 [mu] m 25% (integrated value of the frequency-based) or more, using one containing 15% fine powder of particle size of 80～180Myuemu (integrated value of the frequency-based) or more. The fine limestone powder used in this embodiment was measured with a laser diffraction / scattering particle size distribution measuring apparatus (LA-950, manufactured by Horiba, Ltd.), and the results shown in FIG. 2 (peaks at around 10 μm and around 100 μm). Is obtained).

  Such crushed lime sand and fine limestone powder can be obtained by, for example, a known crushing device or granulating device.

  In the mortar composition 2 of the present embodiment, 14 to 22 parts by weight of cement, 70 to 83 parts by weight of crushed lime sand as fine aggregate, and 3 to 10 parts by weight of limestone fine powder total 100 weights. The volume ratio of cement and aggregate (lime crushed sand + limestone fine powder) constituting the mortar composition 2 is 1: 4 to 1: 7 (in this embodiment, 1: 5). Therefore, compared with the conventional mortar composition in which the volume ratio of cement to aggregate is 1: 3 to 1: 4, it becomes easy to reduce the blending ratio of the cement and, hence, the amount of use, thereby saving resources and It will contribute to cost reduction.

In addition, when the blending ratio of cement is lowered in the conventional mortar composition, the strength of the mortar is lowered, but if the mortar composition 2 of the present embodiment is used, while reducing the amount of cement used as described above, The strength of the mortar 4 to be formed can be increased, and a crack preventing effect is also imparted. The mechanism is that fine limestone powder having a small particle size (5 to 20 μm) improves the solidity of the mortar 4 by entering between the crushed lime sand particles and cement particles, and further, the particle size is large ( 80 to 180 μm). This is thought to be because the fine limestone powder maintains an appropriate distance between the crushed lime sand particles, and the cement particles are uniformly dispersed to assist the complete coating of the cement on the crushed lime sand.

  In addition, when the blending ratio of cement is simply lowered in the conventional mortar composition, the (ball) bearing function for smoothly transporting the fine aggregate that the cement bears is insufficient, and the fluidity of the mortar 4 and thus the workability are reduced. It will fall. However, in the mortar composition 2 used in the present embodiment, the blending ratio of the cement is not simply lowered, but the limestone fine powder having the same particle size as the cement particles and the lime crushed sand particles larger than the cement particles. By blending with limestone fine powder having a small particle size, the bearing function and the fluidity of the mortar 4 that are impaired by the reduction of cement are complemented and enhanced, and it is expected not only to maintain workability but also to improve it. .

  Here, the present inventor has confirmed that it cannot be successfully applied by spraying using a mortar composition containing only cement and crushed lime sand without compounding limestone fine powder at all. This suggests the importance of fine powder.

  And when implementing the formation method of this embodiment, what is necessary is just to add a water reducing agent, a fiber, etc. to the pumping pump 1 other than the mortar composition 2 and the water 3 as needed, and to mix (knead | mix). Since the fluidity of the mortar 4 can be improved as described above, the necessary amount of expensive high-performance water reducing agent that is indispensable when the conventional mortar composition is used is reduced. Down is achieved.

  In general, an excessive amount or a small amount of water added to the mortar composition prevents the formation of a good quality mortar, but the mortar composition 2 of the present embodiment uses crushed lime sand having a property of not absorbing water as a fine aggregate. As a result, the amount of water that is not absorbed by the fine aggregate (outside of the fine aggregate) is very constant compared to the conventional formulation that uses water-absorbing sand as the fine aggregate. This facilitates the stabilization of the quality of the mortar 4 to be formed, and also simplifies the production of a high-quality mortar 4.

  Moreover, as described above, the fine aggregate contained in the mortar composition 2 is crushed lime sand having no water absorption, so that the amount of water added when forming the mortar 4 can be reduced as compared with the conventional blending. The mortar composition 2 contributes to resource saving (water saving) in this respect as well, and even if the amount of water added is reduced as described above, the mortar composition 2 has an appropriate amount of moisture as the mortar 4 due to the fine limestone powder that prevents water separation. Can be held.

  Furthermore, since the mortar 4 by the mortar composition 2 can prevent separation of water by the limestone fine powder, and the hardness and adhesion of the mortar 4 are in a good state, after the supply to the slope N (surface to be constructed) It is possible to reduce or prevent the run-off (flow from the slope N) before drying.

  Moreover, since the mortar composition 2 uses the crushed lime sand which can be stably supplied in various places as a fine aggregate, the spraying construction of this embodiment can be suitably implemented in various places throughout the country.

  In addition, this invention is not limited to said embodiment at all, Of course, it can change and implement variously in the range which does not deviate from the summary of this invention. For example, the following modifications can be given.

  The above forming method is for forming the frame 5 but is not limited to this, and can be applied to the formation of other structures.

  Further, instead of preparing the mortar 4 on site, the mortar 4 prepared in advance in a factory or plant may be carried into the construction site using an agitator vehicle and used.

In the first embodiment, only the pumping pump 1 is used for transporting the mortar 4, but air transport may be used in combination with this pumping. An example thereof will be described as a second embodiment with reference to FIG.

That is, in the second embodiment, the air compressor 12 is connected to the pipe 11 in order to join the high pressure (compressed) air to the mortar 4 to be pumped and to blow the mortar 4 from the spray nozzle 10 to the slope N. It is connected in the middle. In FIG. 3, reference numeral 13 denotes a merging pipe provided in the middle of the pipe 11, and reference numeral 14 denotes an air supply pipe that connects the merging pipe 13 and the air compressor 12.

  The other configuration of the second embodiment is the same as that of the first embodiment, and the description thereof is omitted because it is duplicated.

  Here, in 2nd Embodiment, although the mortar 4 will be sprayed toward the slope (surface to be constructed) N from the spray nozzle 10, the mortar 4 by the mortar composition 2 is as described above. Since the separation of water can be prevented by the fine powder of limestone and the hardness and adhesion of the mortar 4 are in a good state, the rebound loss of the mortar 4 (slope N) when sprayed on the slope N (surface to be constructed) (Dispersion loss due to rebounding) is reduced and prevented.

1 Pumping pump 2 Mortar composition 3 Water 4 Mortar N Slope (surface to be constructed)

Claims (2)

A method for forming a mortar structure in which a mortar is pumped using a pressure pump and placed on a construction target surface, wherein the mortar includes 14 to 22 parts by weight of cement and 70 to 83 parts by weight of fine aggregate. The lime crushed sand and 3 to 10 parts by weight of limestone fine powder having a particle size distribution with frequency peaks at least in two places of 5 to 20 μm and 80 to 180 μm are blended to be 100 parts by weight in total. ,
Use the limestone fine powder prepared by adding water to a mortar composition containing 25% or more of fine powder having a particle size of 5 to 20 μm and 15% or more of fine powder having a particle size of 80 to 180 μm. A mortar structure forming method characterized by the above.   The mortar structure forming method according to claim 1, wherein air is joined to the mortar to be pumped and sprayed from a spray nozzle onto a construction target surface.

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