JPH0160401B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention is widely used as a method for molding cement products with excellent mechanical strength, such as building wall panels, using mortar mixed with reinforcing fibers such as glass fibers. With the required amount of cement mortar GRC mixed with reinforcing fibers being supplied to the frame, vibration is applied to the lower formwork and mortar GRC, and the upper formwork is lowered to press the mortar GRC to form a product in a predetermined shape. This invention relates to a dehydration method in vibration press molding. Conventionally known dehydration methods for this type of vibrating press molding method include: ○B. When the lower formwork has descended to a predetermined position, the vibration and press action are stopped, and then vacuum dehydration is performed from the upper formwork side. How to do it. ○B A method of dehydrating under reduced pressure while the mortar in the mold is flowing by applying pressure and vibration through the upper mold. There is. However, in the former case, water can be sufficiently dehydrated from the mortar surface to a certain depth, but as the surface layer is dehydrated, the cement particle structure in that part becomes denser, so In the case of products with insufficiently dehydrated layer parts, and therefore ribs with large heights and thicknesses, the overall dewatering rate is low.Moreover, immediately after dewatering, the surface layer becomes quite firm and loses its shape. However, after a while, residual water in the deep layers and inside the ribs migrates to the surface layer, causing the whole to become flexible and lose its shape. In addition, in the latter case, the fluidity of the mortar gradually decreases as the dehydration progresses, so that it is difficult to press-form it into a predetermined shape as a product. In view of these circumstances, the purpose of the present invention is to propose a method that can reliably and sufficiently dehydrate even the inside of a product that is thick or has ribs, and that can also be molded into a predetermined shape. has. In order to achieve the above object, the dewatering method in the vibratory press molding method of the present invention includes supplying a required amount of reinforcing fiber-mixed cement mortar to the lower formwork, and applying vibration to the lower formwork and mortar. After lowering the upper formwork and press-forming the mortar into a predetermined shape, dehydration is carried out under reduced pressure from the upper formwork or the lower formwork, or from both sides of the upper formwork and the lower formwork while applying vibration and press pressure to the mortar. This is what we do. Therefore, according to the present invention, the following effects can be expected. a The fluidity of the cement mortar is ensured by applying vibrations, and the upper formwork is lowered in this state without dehydration under reduced pressure, so the fluidity of the mortar is maintained well and press forming into the specified shape is possible. This has the effect of making it easier to carry out reliably. b. Even after the cement mortar is molded into a predetermined shape, the action of vibration and press pressure continues, so
Due to thixotropy, which is one of the characteristics of cement mortar, under static pressure conditions, moisture adsorbed on cement particles is released and separated, and moisture in deep layers smoothly migrates to the surface layer. Therefore, compared to dewatering without vibration as in the conventional method ○A described above, water can be dehydrated much deeper inside the product, and it is easier to mold a product that is firm and firm as a whole and does not lose its shape. Examples of the method of the present invention will be listed below in order of steps based on the drawings. As clearly shown in FIG. 1, the required amounts of cement mortar and glass fibers are simultaneously sprayed into the lower formwork 1. As clearly shown in FIG. 2, the lower formwork 1 is elastically supported via springs 3, 3, and the vibration motor 4 attached to the lower formwork 1 is operated to supply the lower formwork 1 and its interior. While applying vibration to the glass fiber mixed cement mortar GRC,
The upper formwork 2 equipped with the perforated plate 2B and the suction box 2A is lowered and press pressure is applied to the cement mortar GRC through a press machine (not shown), thereby causing the cement mortar GRC to flow smoothly. At this time, no vacuum dehydration is performed. After the upper formwork 2 is lowered to a predetermined position and both the upper and lower formworks 1 and 2 are clamped as shown in Fig. 3 (at this stage, the rib portion A1 has already been formed into the predetermined shape). , While the vibration and press pressure are applied, the suction box 2A of the upper formwork 2 is activated as the vacuum pump (not shown) operates.
By reducing the pressure inside the cement mortar to -100mmHg or more, specifically -400mmHg for 1 minute,
Excess water in the GRC is dehydrated by suction. By the steps described above, a product such as a ribbed single skin panel A shown in FIG. 4 is formed. In the present invention, press pressure is applied during dehydration under reduced pressure in order to prevent the mortar from flowing and the upper formwork from rising from a predetermined position due to the application of vibration. Next, the results of experiments conducted by the inventor will be described.

[Table] In the above example, dewatering was performed under reduced pressure from the upper formwork side.
Dewatering under reduced pressure may be performed from the lower formwork side or from both sides of the upper formwork and the lower formwork.

[Brief explanation of drawings]

The drawings illustrate embodiments of the dewatering method in the vibration press molding method according to the present invention, and FIGS.
The figures are longitudinal sectional views for explaining each process, and FIG. 4 is a longitudinal sectional view of the molded product. 1...Lower formwork, 2...Upper formwork, GRC...cement mortar mixed with reinforcing fibers.

Claims (1)

[Scope of Claims] 1. With a required amount of cement mortar GRC mixed with reinforcing fibers supplied to the lower formwork 1, the upper formwork 2 is lowered while applying vibration to the lower formwork 1 and the mortar GRC to remove the mortar. After press-forming GRC into a predetermined shape, vibration and press pressure are applied to the mortar GRC to perform vacuum dehydration from the upper formwork 2 or the lower formwork 1, or from both sides of the upper formwork 2 and the lower formwork 1. Dehydration method in press molding method. 2. The dehydration method in the vibratory press molding method according to claim 1, wherein the reduced pressure for dehydration is -100 mmHg or more, preferably -200 mmHg or more.