JPS58223655A - Cement composition for glass fiber reinforced mortar - 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 The present invention relates to a cement composition for glass fiber-reinforced mortar that has excellent short-term strength development and prevents long-term alkali deterioration of glass fibers.

General glass fiber reinforced mortar (hereinafter referred to as GRO)
It is used in buildings because it has superior bending spring strength, tensile strength, toughness, etc., and excellent crack resistance compared to ordinary mortar.

However, even though glass fiber is alkali-resistant,
Over the long term, the alkali in the cement in the mortar causes deterioration, resulting in a decrease in bending strength.

In addition, a cement composition for GRO consisting of granulated blast furnace slag-stone wax-cement system with less alkali deterioration has been proposed, but it has drawbacks such as poor short-term strength development and large drying shrinkage. This is a practical problem.

The present inventor has kept this point in mind and has developed GRO of granulated blast furnace slag.
As a result of various studies on the application of this invention, the present invention was completed based on the knowledge that calcium aluminate and gypsum could be used.

That is, in the cement composition for GRO of the present invention, the weight ratio of calcium aluminate to gypsum is based on 100 parts by weight of a hydraulic material consisting of 50 to 80 parts by weight of granulated blast furnace slag and 50 to 20 parts by weight of cement. It is characterized by containing 10 to 60 parts by weight of a cement admixture having a ratio of 1:1 to 6.

The present invention will be explained in detail below.

It is already known that granulated blast furnace slag is used as an admixture for cement to improve various properties of cement such as monosulfate resistance and chemical resistance.
It is specified by JLB as B, Class 0 blast furnace cement. On the other hand, although granulated blast furnace slag itself is a hydraulic material with latent hydraulic properties, its initial strength is considerably lower than that of Portland cement, so it is not widely used in practice.

The present invention aims to prevent alkali deterioration of glass fibers, and uses such granulated blast furnace slag as the main component of the hydraulic material. The hydraulic material according to the present invention is
Granulated blast furnace slag 50-80% by weight and cement 50-20%
It is made up of heavy weights. The 50% by weight of granulated blast furnace slag is the minimum percentage necessary to prevent deterioration of glass fibers, and the maximum percentage was limited to 80% by weight from the viewpoint of initial strength development. The preferred ratio is 60 to 75 parts
It is the width.

As granulated blast furnace slag, it can be used without any problem as long as the basicity is about 1.80 or higher, and the fineness is 2500 cm2/f or higher in plain value, preferably 3500 or higher.
6000 crrr'vv. Further, as the cement, normal, early strength, super early strength, Nakaura heat, and white Portland cement can be used.

Next, the cement admixture according to the present invention will be explained.

Calcium aluminate has Oa, 0 minutes and A420. It is obtained by heat treating a raw material containing
0ASOA2. 03A, O□2Aヮ.

03A, 0aSO, 03A, 0aF2. O,,A
Minerals such as 70aF2 and 20 to 65 weights of GRO! i%
One or two types of calcium aluminate amorphous substances contained
More than a species.

In the case of calcium aluminate amorphous, its OaO
The reason for limiting the content is that when the weight is 20%, the initial strength development is poor, and when the weight exceeds 65%, the setting time cannot be adjusted when mixed with hydraulic materials, making it impractical. This is because it is lacking.

On the other hand, as the other component of the cement admixture, gypsum can be used regardless of whether it is dihydrate, hemihydrate, or anhydrite, but type 1 anhydrite is especially desirable because it has good strength. .

The proportion of calcium aluminate diface is 1 by weight.
1 to 3, and at other ratios, the obtained GRO
This is undesirable because the initial strength of the material decreases or the amount of contraction or expansion increases.

For cement admixture fineness: 3000 crn
'／? The above is preferable.

The blending ratio of the cement admixture to 100 parts by weight of the hydraulic material is 10-30 parts by weight, preferably 15-25 parts by weight.If it is less than 10 parts by weight, there is no effect of increasing the initial strength, and the There is little increase in strength development even after a certain temperature, and it is not economical. Calcium aluminate and gypsum may be blended separately without being mixed in advance.

When a cement admixture consisting of calcium aluminate and gypsum is mixed into a hydraulic material, setting may begin in a very short period of time due to water utilization of the calcium aluminate. In such a case, a retarder consisting of citric acid, tartaric acid, gluconic acid, malic acid or a soluble salt thereof or a mixture thereof with an alkali carbonate, which has a retarding effect on the setting of cement, is used.

GRO can be manufactured by simultaneously blowing mortar with a mortar spray gun and glass fiber with compressed gas from a chopper gun, or by mixing mortar and lath fibers in a mixer and filling them into a mold. etc., and there are no restrictions on the molding method.

For example, to explain the case of making GRO by the spraying method, mortar made of a hydraulic material mixed with a predetermined amount of sand and water, and water slurry 11- as a cement admixture are mixed near the nozzle tip while forming the mold. GR with excellent strength is achieved by spraying glass fiber on the surface and at the same time spraying glass fiber separately.
O is obtained.

GRO using the cement composition of the present invention sets and hardens due to the action of the cement admixture, develops the strength necessary for demolding in a short time, and has good long-term strength growth and excellent durability. Become. Since it is still low alkaline,
Deterioration of glass fiber is also reduced. The strength of GROM products is
It is adjusted by the ratio of calcium aluminate and gypsum in the cement admixture, or the amount added to the cement. In addition, by insulating with hot air, steam, etc., it is possible to obtain the strength necessary for removing the frame in a shorter time.

When using a setting retarder, it may be added to either the hydraulic material or the cement-mixed paulownia, or both, and the amount should be 2 weight ratios to the combined weight of the hydraulic material and the cement-mixed paulownia. The following are appropriate. Also, if you use a commercially available cement water reducer, it will have a corresponding effect.

As for the type of glass fiber, ordinary glass fiber can be used as appropriate, but from the viewpoint of durability, alkali resistance 1
Uniform lath fibers are preferred. The ratio of this to hydraulic materials and cement mixture is usually 1 to 10% by weight.
However, it is not limited to this.

Next, the present invention will be further explained with reference to Examples.

Example 1 Granulated blast furnace slag (plain value 3800 cm2/f/
) 70 parts by weight, ordinary Portland cement 60 parts by weight, 100 parts by weight of hydraulic material, 80 parts by weight of silica sand, 32 parts by weight and cement water reducer Kao soap ■Product name ("Mighty 150J") 1 part by weight Mortar was prepared by mixing with a mortar mixer.Separately, OaO4
Cement admixture 1 consisting of a calcium aluminate amorphous material containing a double glutinous material and a ■-type anhydrite powder in a weight ratio of 1:2
ooxt part, 4 parts by weight of sodium citrate, and 60 parts by weight of water were mixed to prepare a cement admixture slurry.

Conomortar, cement admixture slurry with a ratio of 20% by weight of cement admixture components to the hydraulic material, and 5% to the total amount of the hydraulic material and cement admixture components.
Commercially available alkali-resistant glass fiber (length 20 tan)
) and just before molding on the formwork to obtain a thickness of ζ10+n.
When I molded a +n GRO plate, it hardened in about 20 minutes and became 6
The mold was removed after 0 minutes.

The bending strength after 5 hours was 114 K4f/cm''.

In addition, 20 minutes after forming the GRO plate, steam curing at 50°C was performed for 30 minutes, and the bending strength was 130 f/cr.
Letter obtained from n2's GRO board.

Furthermore, the bending strength of the 28-day-old specimen was immersed in hot water at 700C for 10 days, and the strength ratio to the bending strength before being immersed in hot water was determined to be 0.8.
It was 2.

Examples 2 to 11, Comparative Examples 1 to 9 Tests were conducted in the same manner as in Example 1, except that the compositions and amounts of the hydraulic material and cement mixture were varied. The results are shown in the table.

From 1゛゛All white

Claims (1)

[Claims] Blast furnace granulated slag weight - 80 weight factor and cement 50-20
Heavy 1. A cement composition for glass fiber reinforced mortar, which contains 10 to 30 parts by weight of a cement admixture having a weight ratio of calcium aluminate to gypsum of 1 to 1 to 100 parts by weight of a hydraulic material consisting of Z. thing.