JPS61291442A - Manufacture of cementitious precast panel - 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 [Industrial Field of Application] The present invention relates to a method for manufacturing cementitious precast panels by extrusion molding.

[Conventional technology]

Methods for manufacturing cement-based precast panels by extrusion molding are already known, and some have been put into practical use.

However, all cement-based precast panels manufactured by conventional extrusion molding methods have low strength, especially tensile strength and bending strength, and have only been used as finishing materials for curtain walls, partition walls, and other objects. do not have.

[Problem that the invention seeks to solve]

In view of the above-mentioned current situation, the present invention has developed a high-strength, high-quality cement-based precast panel that has the strength to be used as a structural material and can be applied, for example, to the construction of composite concrete walls using cement-based precast panels and cast-in-place concrete. This paper proposes a method for manufacturing cement-based precast panels that can be manufactured by extrusion molding.

[Means for solving problems]

The method for producing a cement-based precast panel according to the present invention involves extruding a cement mortar obtained by adding a water-reducing agent or a water-reducing retardant and a water-soluble sizing agent to hardened cement mortar while kneading it in a vacuum. It is unique in that it manufactures precast panels.

〔Example〕

Example■ Early strength Portland cement 3.6kg Aggregate (brick powder/mixture 1.Qu+ or less) 1.8kg
Water 0.
Hyfluid (trade name: a polymer whose main component is alkyl sulfonate) was added as a water reducing agent to 43 kg of slump O hard cement mortar having the above composition.
0.024kg MC (methyl cellulose) agent as water-soluble glue,
0.040kg Styrene butadiene rubber (SBR) jc, 0.6 as a polymer dispersion for mixing with cement
Polymer cement ratio with addition of kr 6.7χWater-cement ratio 21.9χMC-cement ratio
1.1χWater reducer cement ratio 0.
A 67χ polymer cement mortar is kneaded using an Omnimixer (trade name, manufactured by Chiyoda Giken Kogyo Co., Ltd.).

The polymer cement mortar obtained through the above process is kneaded in a vacuum state using a known vacuum extrusion molding machine (that is, while degassing the air contained in the kneaded material by reducing pressure), and is continuously molded into long panels. After extrusion molding and cutting to a predetermined size, wet curing and dry curing are performed to produce a cement-based precast panel.

In the above manufacturing method for cement-based precast panels, the cement mortar is made into a hard paste with a slump of 0 in order to produce a dense and high-strength molded product (panel). It's also for the same reason.

The water reducing agent is used to impart fluidity to hardened cement mortar for a predetermined period of time so that extrusion molding using a vacuum extrusion molding machine can be performed easily and favorably at a relatively low pressure.
Mixing of cement-mixing polymer dispersion and other mortar components - Used to easily and thoroughly mix the cement-mixing polymer dispersion and other mortar components so that the cement-mixing polymer dispersion and the like are uniformly dispersed.

A water-soluble sizing agent (MC agent) is used to increase the viscosity of the polymer cement mortar so that extrusion molding can be performed well without cracking.

The purpose of using early-strength Portland cement is to quickly develop the strength of molded products, as well as to use it as a water-soluble glue (MC agent).
is used to further increase the viscosity of the polymer cement mortar.

That is, since early-strength Portland cement has smaller particles than ordinary Portland cement, when it is fluidized by adding a water-reducing agent, the particles slip more easily and the viscosity increases.

Polymer dispersion for cement mixing is used together with cement as a binding material for aggregate, and has the effect of reinforcing the crystals of cement and aggregate, so it improves the bending strength, tensile strength, and durability of molded products (panels). Impact resistance will be improved.

The strength characteristics of the cement precast panel manufactured by the above method are as follows, and it can be used for constructing synthetic concrete walls and as other structural materials.

Bending tensile strength (5 days old) 226 pupils/- Pure tensile strength (28 days old) 103 kir/cj As is well known, there is a proportional correlation between compressive strength and water-cement ratio. In the case of the hard-mixed cement mortar in this example, since the water-cement ratio is 21.9%, it is clear that a considerable compressive strength can be obtained.

In the above examples, brick powder was used as the aggregate, but other artificial aggregates (artificial lightweight aggregates such as pilton and mesalite made of expanded shale, shirasu balloons made of volcanic ash,
Such as porcelain ceramic aggregate. ) may be used. Although sea sand or mountain sand can be used as the natural aggregate, it is preferable to use river sand in order to improve the quality of the molded product.

Furthermore, in the above example, styrene butadiene rubber (SBR), which is one of the aqueous polymer dispersions, was used as the polymer dispersion for cement mixing, but acrylonitrile butadiene rubber (NBR), which is one of the aqueous polymer dispersions, was used. ), methyl methallylate butadiene rubber (MBR), butadiene rubber (B
Rubber latex such as R), polypropylene (P
), polyacrylic acid ester (PAE), ethylene vinyl acetate (EVA), and other resin emulsions can be used.

As the water-soluble glue, polyvinyl alcohol can be used in addition to the MC agent.

If the polymer cement mortar cannot be maintained in a fluidized state for the required time simply by adding a water reducing agent, the time in which it remains fluidized can be controlled by adding a setting retarder.

Below, other embodiments of the present invention are shown, the manufacturing process of cement-based precast panels is the same as the previous embodiments,
Since the only difference is the formulation of the cement mortar used, only the formulation table will be described. In addition, the cement mortar before adding the water reducing agent or the water reducing retardant is a hard mix with 0 slump in any of the examples.

Example ■ Early strength Portland cement 20.0 k
TR aggregate (river sand, grain size 1.5) 10.
0 k+r emulsion (SBR)
OkgM Cti'I
O, 220kg water reducing agent (high fluid)
0.140! water
4.2601 water cement ratio 22
．． 0% (including water reducer) Polymer cement ratio 0% MC cement ratio 1.1% Water reducer cement ratio 0.84% Example ■ Early strength Portland cement 20.0 k
g Aggregate (river sand, grain size 1.5m) 10.0
kg emulsion (SBR) 3
．． 33 Pupil MC agent 0.22
0kg water reducing agent (high fluid') 0
．． 1671 water
2.0021 water cement ratio 20.8
% (including water reducing agent) Polymer cement ratio 6.7% MC cement ratio 1.1% Water reducing agent cement ratio 1.0% (Note) In the above formulation, it has been confirmed that there is a lack of water as an extrusion molded product. It was done. Therefore, the above document 1
Add 160cc of water to 2.65kg and mix again. Water-cement ratio: 23.0% (including water-reducing agent) Polymer-cement ratio: 6.7% MC-cement ratio: 1.1% Water-reducing agent-cement ratio: 1.0% By doing this, a desired extrusion molded product was obtained.

Example ■ Early strength Portland cement 20.0 k
g Aggregate (brick powder/particle size 1.0m) 10.0
kg emulsion (SBR)
3.33 kgMC agent
0.220, H water reduction retardant (High Fluid R)
0.167 fi water
2.4351 water cement ratio 2
3.0% (including water reduction retarder) polymer cement ratio 6
．． 7% MC cement ratio 1.1% Water reduction retardant cement ratio 1.0% Example ■ Ordinary Portland cement 20.0 k
g Aggregate (river sand, grain size 1.5m) 10.0
kg emulsion (SBR) O
kgMC agent 0.240k
g Water reducing agent (high fluid) 0.16
77! water
4.2331 Water-cement ratio 22.0% (including water-reducing agent) Polymer-cement ratio 0% MC-cement ratio 1.2% Water-reducing agent-cement ratio 1.0% Example ■ Ordinary Portland cement 20.0 k
g Aggregate (river sand, grain size 1.5 dragon) 10.0
kg emulsion (SBR)
3.33 kgMC agent
0.240kg water reducing agent (high fluid)
0.1677! water
2.23! M water cement ratio
22.0% (including water reducing agent) Polymer cement ratio 6.7% MC cement ratio 1.2% Water reducing agent cement ratio 1.0% In order to manufacture a precast panel by extruding a cement mortar obtained by adding a water reducing agent or a water reducing retardant and a water-soluble sizing agent to cement mortar while kneading it in a vacuum,
For example, it is possible to obtain high-strength, high-quality cement-based precast panels that can be used as structural materials for buildings, such as cement-based precast panels used in constructing composite concrete walls using cement-based precast panels and cast-in-place concrete.

Claims (1)

[Claims] A precast panel is manufactured by extrusion molding a cement mortar obtained by adding a water reducing agent or a water reducing retardant and a water-soluble sizing agent to hard-mixed cement mortar while kneading it in a vacuum state. Method for manufacturing cement-based precast panels.