JP5679794B2 - Mortar or concrete spraying method and apparatus - Google Patents

Description

  The present invention relates to a mortar or concrete spraying method and an apparatus therefor.

  For example, when forming a grid-like frame by spraying mortar material or concrete material on a pre-formed formwork on a high slope, conventional water, cement, sand as fine aggregate, In order to efficiently perform high-pressure spraying compared with a mortar or concrete spraying method in which gravel or crushed stone as coarse aggregate is kneaded in advance, as shown in Patent Document 1 below, mortar There is a mortar or concrete spraying method called the so-called separate pumping method, in which cement milk and aggregate constituting the material or concrete material are separately pumped and then mixed to spray a mortar material or concrete material to form a frame. . Then, for example, sand as fine aggregate is moved in a connecting hose having a length of about 400 m by compressed air and mixed with cement milk at a position of about 10 m before the spray nozzle to obtain a mortar material. An operator supported by a lifeline sprays mortar material on the mold while holding a spray nozzle to form a grid-like frame. However, such a separate pumping method may cause the following problems, for example.

  Cement milk and sand were not completely mixed, and there was a problem that the strength of mortar was reduced and rebound occurred. In other words, since cement milk and sand do not mix evenly, when mortar material is sprayed, sand that is not covered by cement milk rebounds on the slope (rebound), and the rebound sand accumulates on the slope and spraying work Is temporarily interrupted, air is blown to the slope from the spray nozzle, and the accumulated sand needs to be removed from the slope. In addition, it is necessary to prepare a large amount of sand in advance in consideration of the loss of sand due to rebound, leading to an increase in cost.

  In recent years, the sand has a higher quality and often contains a silt content. When sand containing silt other than coarse sand and fine sand is used as the sand, the silt is stuck in the hose that feeds the sand under pressure, and the hose is likely to be clogged.

  Therefore, in order to solve such a problem, as an apparatus used in the separate pressure feeding method, for example, as shown in Patent Document 2 below, bone that supplies not only sand but also water via a hose that forms an aggregate supply path is used. It is obtained by mixing a material pressure feeder, a cement milk supply means for supplying cement milk via a cement milk supply path separately from the sand and water, and a mixing means for mixing the sand, water and the cement milk. There is a mortar spraying device with a spray nozzle for spraying the mortar material produced.

  According to the mortar spraying apparatus shown in Patent Document 2 in which water is added to the aggregate side, for example, there are the following advantages. In the hose that forms the aggregate supply path, water exists around the sand, so that the inside of the hose is in a hydrophilic state. Therefore, in the mixing means, the familiarity with the cement milk is improved, and the sand is uniformly mixed with the cement milk. Therefore, the mortar strength is improved, and the occurrence of sand rebound can be avoided when the mortar material is sprayed.

  Even when silt is contained in addition to coarse sand and fine sand, the moisture content with respect to the weight of the sand is set in a desired range, so that the moisture content exceeds the moisture content at which the silt is compacted by the wall surface of the hose. It is possible to avoid a situation in which the hose is clogged with the silt stuck in the hose.

Japanese Patent No. 3592604 Japanese Patent No. 4229260

  However, in the separate pumping method in which water is added to the aggregate side, the amount of water added to the aggregate side is required to be very strict, and if the amount of water added to the aggregate side is too small, The material transport hose is clogged, and it takes a lot of time to restore it, and the economic loss also increases (breakage of the aggregate transport hose due to clogging, the contents of the cement milk transport hose harden and become useable Etc.) Conversely, if the amount of water added to the aggregate side is too large, the mortar material that is finally formed will become watery and droop, and the amount of water that can be used for cement milk will be reduced. End up. That is, the viscosity of cement milk becomes high and the transportability is lowered.

  Therefore, it is necessary to be careful when setting the amount of water to be added to the aggregate side, but the aggregates actually used differ in their physical properties, water absorption rate, water retention rate, etc. Depending on the weather conditions (temperature, humidity, weather, etc.), even with the same aggregate, the moisture content will change in just a few hours while waiting (before being put into the spraying device). It is necessary to check the condition of the aggregate and to have a great deal of experience and knowledge. In particular, in the case of an aggregate having a low water absorption rate, the desired consistency cannot be obtained unless the water cement ratio is made lower than the water cement ratio (55 to 60%) of mortar using general aggregate. In addition, efforts have been made to adjust not only the amount of water added to the aggregate side but also the total amount of water.

  In addition, the above-mentioned trouble that occurs when too little water is added to the aggregate is very serious, and it is possible to damage the spraying device itself (such as a hose), so this can be avoided reliably. How to do is being sought.

  The present invention was devised to solve the above-mentioned problems in the separate pumping method, and the purpose thereof is to convey the aggregate and the cement milk regardless of the aggregate used in the separate pumping method. It is to provide a mortar or concrete spraying method and apparatus capable of forming a sprayable material having high formability without lowering the thickness.

In order to achieve the above object, the present invention comprises an aggregate supplied from an aggregate pumping machine via an aggregate supply path, and cement milk supplied from a cement milk supply means via a cement milk supply path. In a mortar or concrete spraying method in which mortar material or concrete material is sprayed by mixing to supply a part of water constituting the mortar material or concrete material from the aggregate pump It was added to the aggregate to be by using some air pressure of the aggregate supply path, while divided parts of water added to the aggregate at the end portion of the aggregate supply passage The air pressure of the spray nozzle is lowered (claim 1).

Further, according to another aspect of the present invention, an aggregate pumping machine that supplies aggregate and water via an aggregate supply path, and cement milk is supplied via a cement milk supply path separately from the aggregate and water. Mortar or concrete spraying device comprising cement milk supply means, mixing means for mixing the aggregate and water with the cement milk, and a spray nozzle for spraying the mortar material or concrete material obtained by mixing In the terminal part of the aggregate supply path, a part of the air pressure in the aggregate supply path is used to remove a part of the water added to the aggregate, and the air of the spray nozzle Provided is a mortar or concrete spraying device provided with water removing means for reducing the pressure (Claim 2).

  And it is preferable that the said water removal means is provided with the adjustment part which adjusts the quantity of the water removed (Claim 3).

  In this invention, mortar or concrete spraying that can form a sprayable material with high formability without reducing the transportability of the aggregate and cement milk, regardless of what aggregate is used in the separate pumping method. A method and apparatus can be provided. That is, aggregates with extremely low water absorption (sand mainly made of quartz, blast furnace slag, etc.) and aggregates with low water retention (sand with large particle size and almost no silt) Even if there is, the desired mortar or concrete can be sprayed without closing the aggregate transport hose during the transport of the aggregate. Further, even when using normal aggregate, a large amount of water having a sufficient safety factor can be added to the aggregate side, and the aggregate can be transported more safely and reliably than before. Furthermore, the water-cement ratio of the mortar or concrete to be sprayed can be reduced as compared with the conventional method, and a mortar or concrete having higher strength can be formed.

  In short, in the conventional separate pumping method, for example, water for forming mortar (hereinafter referred to as A) is divided into water for adding aggregate (hereinafter referred to as X) and water for forming cement milk (hereinafter referred to as Y) (A = X + Y). ), And trying to keep the amount of A low by adjusting the amounts of X and Y to such an extent that both aggregate and cement milk can be conveyed. On the other hand, according to the present invention, excess water (hereinafter referred to as β) can be drained immediately before cement milk mixing even if the amount of X is larger by α (> 0) (X + α). It is no longer necessary to go on a tightrope (it is now possible to transport aggregate with a margin). In other words, in the present invention, for example, the water forming the mortar is changed from [X + Y] to [(X + α) −β + Y]. Here, if X + Y = A and (X + α) −β + Y = A ′ (A ′: water used in the present invention to form mortar), α ≦ β and A ′ ≦ A. It goes without saying that the strength of the resulting mortar and the like is improved by lowering the water cement ratio (suppressing A low). In addition, the separate pumping method has higher pressure than the general spraying method of spraying mortar material or concrete material in which water, cement and aggregate are pre-kneaded, so the spraying of the separate pumping method requires arm strength. However, in this invention, since the pressure in the aggregate supply path is partially used for removing moisture, the air pressure at the spray nozzle is lowered, and there is a specific advantage that the worker can easily perform the construction.

BRIEF DESCRIPTION OF THE DRAWINGS It is whole structure explanatory drawing which shows one Embodiment of this invention. It is a principal part longitudinal cross-sectional view in the said embodiment. It is a figure which shows other embodiment of this invention which provided the hole for water removal in the position different from the said embodiment.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a mortar material obtained by mixing aggregate and water supplied from an aggregate pumping machine and cement milk supplied from cement milk supply means (usually the weight ratio is cement 1: sand 4). : Water 0.5)) showing the formation status of the legal frame by spraying and the greening protection status of the slope by spraying the vegetation base material. FIG. 2 shows the configuration of the mixing means for mixing the aggregate and water with the cement milk.

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

  In this embodiment, a mortar material in which cement, quartz sand, which is an example of a fine aggregate having a low water absorption rate, and water are mixed as a spraying material will be described. Applicable to concrete materials in which normal sand or blast furnace slag is used as aggregate, cement, fine aggregate, and coarse aggregate such as gravel, gravel and crushed stone, and water. Needless to say. Here, the water absorption rate of the aggregate indicates the degree of voids in the aggregate, and in the case of a fine aggregate, for example, it is an index of water that each grain of sand can hold inside the particle.

  The mortar material 4 spraying device (hereinafter referred to as mortar spraying device) D includes an aggregate pump 9 for supplying the fine aggregate 7 and water 8a, and an air compressor 10 connected to the aggregate pump 9. , A pump for pressure feeding (for example, a piston type pump, a squeeze type pump) 14 as a cement milk supply means for supplying cement milk 13 obtained by mixing cement 11 and water 8b, and an aggregate supply path i (see FIG. 2). The fine aggregate 7 and water 8a fed through the hose 15 forming the water and the cement milk 13 (11, 8b) fed through the hose 16 forming the cement milk supply channel m are mixed, and mortar A portable mixing device 17 serving as mixing means for discharging the material 4 and a mortar material spray nozzle 20 for spraying the mortar material 4 obtained by mixing. It becomes more mainly. And in this invention, it is comprised so that the part 8a may be added to the said fine aggregate 7 supplied from the aggregate pumping machine 9 among water 8a, 8b which comprises the mortar material 4. FIG.

  Further, the mortar spraying device D has a hose 19 for feeding mortar material connected to a mortar discharge port 18 located on the most downstream side of the portable mixing device 17. A material spray nozzle 20 is provided. The hose 19 for pressure feeding the mortar material has a length including the mortar material spray nozzle 20 of 3 to 20 m so that the spraying range of the mortar material 4 is about 3 to 20 m around the portable mixing device 17. The portable mixing device 17 is installed in the vicinity of the nozzle 20. The hose 15 forming the aggregate supply path i for pumping the fine aggregate 7 and the water 8a is composed of a connecting hose having a length of about 400 m at the maximum. A short hose is connected. The fine aggregate 7 and the water 8a 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.

  And the supply amount of the cement milk 13 (11, 8b) pumped by the pump 14 for pumping as the cement milk supply means is set and changed by a discharge amount gauge provided in the pump 14, and in advance or in real time. By adjusting the discharge amount of the cement milk 13 (11, 8b) by the pump 14 according to the measured amount of the fine aggregate 7 and the pressure of the water 8a to be pumped through the hose 15, the fine aggregate 7 and The mixing ratio of water 8a and cement milk 13 (11, 8b) can be arbitrarily controlled.

  Hereinafter, a characteristic configuration will be described.

  The portable mixing device 17 includes, in order from the upstream side, an introduction cylinder 21 in which the hose 15 forming the aggregate supply path i is connected to the upstream end, the mortar material pressure feeding hose 19 and the introduction. Between the cylinders 21, both the cylinders 19 and 21 have a mixing cylinder 22 provided in a concentric connection. The introduction cylinder 21 forms an introduction flow path j for introducing the fine aggregate 7 and the water 8a flowing through the aggregate supply path i by pumping to the downstream side (the mortar discharge port 18 side). The mixing cylinder 22 includes a communication channel n formed so as to communicate with the introduction channel j in order to mix the fine aggregate 7 and the water 8a and the cement milk 13 (11, 8b), It functions to form the mixing channel k by joining the cement milk supply channel m. Q in FIG. 2 indicates the joining position of the communication channel n and the cement milk supply channel m. The introduction cylinder 21 has the same inner diameter as the inner diameter e of the hose 15, and the female thread portion 23 for connecting the mixing cylinder 22 concentrically and the hose 15 are concentric. Male threaded portions 24 for connection are provided at the downstream end and the upstream end, respectively. On the other hand, the inner diameter E of the mixing cylinder 22 is slightly larger than the inner diameter e of the hose 15 for pumping the fine aggregate 7 and the water 8a (for example, the same diameter may be 3 to 3 times). Then, a male screw portion 25 formed so as to connect the hose 19 for feeding mortar material concentrically to the outer peripheral surface portion of the discharge port 18 with the downstream side (the mortar material discharge port 18 side) being squeezed in order. Have. In addition, the cement milk 13 is placed on the cylindrical wall 22a of the mixing cylinder 22 in the vicinity of the connection portion of the introducing cylinder 21 (at a position downstream of the female thread 23 of the introducing cylinder 21 in the cylindrical wall 22a). An injection cylinder portion 26 of (11, 8b) is formed. Although not shown, an internal thread portion for connecting a cement milk pouring cock is formed on the cylindrical wall 22a in the vicinity of the connecting portion of the mixing cylinder 22, and the cement milk 13 (11, 8b) is formed on the cock. ) May be configured to be connected. Further, when the number of cement milk injection ports is two or more, the mixing efficiency is further improved.

  Reference numeral 40 denotes a protrusion, which is provided downstream of a water removal hole 31 described later and upstream of the joining position Q of the communication flow path n and the cement milk supply path m. In this embodiment, the communication channel n is provided. The protrusion 40 is provided with the fine aggregate 7 flowing into the mixing cylinder 22 from the aggregate supply path i through the introduction cylinder 21 by pressure feeding on the tube wall of the introduction cylinder 21. It has a function of dispersing on the downstream side of the water removal hole 31 having a diameter of about 1 inch. The protrusions 40 have, for example, a substantially hemispherical shape, and a plurality (for example, five) are provided at appropriate intervals in the circumferential direction along the inner wall of the mixing cylinder 22 constituting the communication channel n. Has been placed. That is, the fine aggregate 7 that reaches the portable mixing device 17 through the hose 15 goes further downstream from the introduction flow path j through the protrusions 40 in the communication flow path n. The water is normally conveyed until the water is removed through the water removal hole 31 provided in the introduction cylinder 21, and after the water is removed through the water removal hole 31, When there is the fine aggregate 7 that is solidly flowing along, the fine aggregate 7 collides with the protrusion 40 when passing through the protrusion 40 in the communication flow path n, and is obliquely upward. As a result, the fine aggregate 7 that has flowed in a solid state is dispersed, and the fine aggregate 7 including the fine aggregate 7 dispersed in the communication flow path n is made of cement milk. The mortar material 4 is formed by coating each grain. Further, the protrusions 40 arranged in the circumferential direction may be provided in a plurality of rows (for example, two rows) with an appropriate interval in the flow direction of the communication channel n (the axial direction of the communication channel n), In this case, it is preferable that the adjacent rows of protrusions 40 be configured so as to be offset from each other in the circumferential direction. Although the shape of the protrusion 40 is not limited to a hemispherical shape, the shape of the protrusion 40 is less likely to receive resistance from the fine aggregate 7 to be transported, thereby preventing clogging in the communication channel n. This is desirable.

  Further, the introduction cylinder 21 removes a part of the fine aggregate 7 and the water 8a flowing through the introduction flow path j by pumping depending on the mortar material 4 spraying state from the spray nozzle 20. Therefore, it has a water removal means 30 that forms a branch channel p that branches from the introduction channel j and reaches the water outlet (discharge port) d. The water removal means 30 includes a water removal hole 31 having a diameter of about 1 inch provided on the tube wall of the introduction cylinder 21 and a branch flow path branched from the introduction flow path j through the hole 31. A branch cylinder (branch pipe) 32 that is a narrow pipe (diameter of about 1 inch) forming p, and a valve that is provided in the middle of the branch cylinder 32 and can adjust the amount of water to be removed, for example. And a flexible hose 34 having a length of about 5 m connected to the downstream end of the branch cylinder 32 and having a moisture outlet d. 35 is a water receiving member such as a bucket for receiving the water to be removed. And the said branch cylinder 32 is diagonally extended in the direction opposite to the conveyance direction (direction shown by arrow R in FIG. 2) of the said fine aggregate 7 and the water 8a from the said hole 31 for water removal. The angle θ formed between the axis of the introduction cylinder 21 and the axis of the branch cylinder 32 is an angle at which the fine aggregate 7 can be prevented from flowing into the branch flow path p, that is, the fine aggregate 7 and the water 8a. Is set to a size within a range in which only a part of the water 8a can be ejected in the form of a mist from the introduction flow path j where the pressure is fed, and the angle θ is, for example, 10 ° ≦ θ ≦ 90 °. If the flow of the aggregate is not determined, a part of the aggregate is discharged together with the water. Therefore, in order to avoid this situation, the hole 31 for water removal is a fine aggregate conveyed in the hose 15. 7 (an example of aggregate) is preferably provided in the opposite direction. Specifically, the introduction cylinder 21 and the aggregate supply path i (the hose 15) on the upstream side from the introduction cylinder 21 are arranged so as to be approximately linear for about 3 to 10 m, and the introduction cylinder 21 is arranged. In a cross-sectional view, for example, as shown in FIG. 3, a water removal hole 31 is provided so as to be substantially upward in the vertical direction, or when the hose 15 immediately before the introduction cylinder 21 is curved, a curve is provided. It is preferable to provide the water removal hole 31 so as to be in the inner direction. In such a state, the position where the aggregate flows in the hose 15 can be controlled, and the introduction cylinder 21 is arranged so that the branch flow path p faces in the direction opposite to the flow of the aggregate in the R direction. By providing the branch cylinder 32 having the hole 31 for water removal, it is possible to effectively remove only excess water that is pumped in the hose 15 (aggregate supply passage i) and the introduction passage j together with compressed air in a substantially mist form. It becomes possible to remove (the aggregate becomes difficult to be discharged together with surplus water). And the said adjustment part 33 can adjust the quantity of the water removed by the operator according to the mortar material 4 spraying condition from the spray nozzle 20 so that the sprayed mortar may not droop.

  Next, a mortar placing method implemented using the spraying device D having the above-described configuration will be described. The mortar placing method can be carried out by driving the aggregate pressure feeder 9, the air compressor 10, and the pressure pump 14 and moving the mortar material spray nozzle 20 to an appropriate position. According to the said structure, since there is sufficient water 8a on the aggregate side until it reaches the introduction cylinder 21, the transportability of the fine aggregate 7 is good, and it is necessary to drain water during the mortar material 4 spraying. When the operator operates the valve of the adjusting unit 33 to adjust the flow rate of the water to be removed, excess water is removed, and then the fine aggregate 7 is immediately coated with the cement milk 13. As a result, the mortar material 4 is formed and sprayed from the spray nozzle 20 at the tip to the construction target site N with the momentum. The length of the hose 19 from the merging portion (merging position) Q of the cement milk to the spray nozzle 20 is 3 to 20 m, and is preferably 10 m or less from the viewpoint of the spray pressure and workability. In the case of this embodiment, 5 m was used. Further, in the water removing means 30, a hose 34 having a length of about 5 m is connected to the branch cylinder (branch pipe) 32, which is a narrow pipe, so that a water outlet d can be provided in a place that does not interfere with the construction. it can. A water receiving member 35 such as a bucket for receiving water discharged from the moisture outlet d is preferably provided.

  Thus, by lowering the water-cement ratio (W / C) of the mortar material 4, the entanglement between the cement milk 13 and the fine aggregate 7 is improved, and a mortar having high consistency is formed and the strength of the mortar. Will also improve. And even if the initial composition of the water cement ratio (W / C) of the mortar material was 55%, the finally sprayed mortar material 4 had a water cement ratio (W / C) of 43%.

  In this embodiment, since the aggregate having a low water absorption rate is used, a part of the water added to the aggregate is removed, but the device of the present invention is a part of the water added to the aggregate. Of course, it can be used even when ordinary sand that does not need to be removed is used for the aggregate. In this case, specifically, the valve or the like of the adjusting unit 33 constituting the water removing unit 30 may be kept in a water-stopping state during the work.

4 Mortar material 7 Aggregate 8a Water 9 Aggregate pumping machine 13 Cement milk 14 Cement milk supply means 17 Portable mixer 20 Spray nozzle 30 Water removal means i Aggregate supply path m Cement milk supply path D Mortar spraying apparatus

Claims (3)

A mortar material or a concrete material is prepared by mixing the aggregate supplied from the aggregate pumping machine through the aggregate supply path and the cement milk supplied from the cement milk supply means through the cement milk supply path. In a mortar or concrete spraying method for spraying a material or a concrete material, a part of water constituting the mortar material or the concrete material is added to the aggregate supplied from the aggregate pump, and the aggregate supply by using part of the air pressure in the road, as well as divided portions of water added to the aggregate at the end portion of the aggregate supply path, and characterized by lowering the air pressure of the spray nozzle How to spray mortar or concrete. An aggregate pump for supplying aggregate and water via an aggregate supply path, a cement milk supply means for supplying cement milk via a cement milk supply path separately from the aggregate and water, the aggregate and A mortar or concrete spraying device comprising a mixing means for mixing water and the cement milk, and a spray nozzle for spraying the mortar material or concrete material obtained by mixing, the mortar or concrete spraying device comprising: at the end that, by using part of the air pressure of the aggregate supply path, thereby removing a part of water added to the aggregate, provided water removal means for lowering the air pressure of the spray nozzle Mortar or concrete spraying equipment characterized by. The mortar or concrete spraying device according to claim 2, wherein the water removing means includes an adjusting unit that adjusts an amount of water to be removed.

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