JPS5884166A - Mixed cementitious material - 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 mixed cementitious materials used in the production of glass fiber reinforced cement (GRC) and further used as GRC.

The present applicant has previously reported that the durability of GRC is significantly improved by adding a low-alkaline pozzolan such as ply ash to a low-alkaline cement in a much larger amount than conventionally.

One of them is Japanese Patent Application No. 1988-88865, filed on March 77, 1978, which states: ■ ``7 parts per m of cement/m, volcanic ash, white clay, clay. , silica powder, and glass powder in an amount of i, s to 2 parts by weight of at least seven types of admixtures selected from silica powder and glass powder to make nine mixed cement materials.

The other one is patent application No. 56-8826 filed on the same date.
No. 4, which is: ■ "Ultra-fast hardening cement/fly ash,
``A mixed cementitious material containing at least seven admixtures selected from volcanic ash, clay, clay, silica powder, and glass powder added in an amount of O, a ~ 200 parts by weight.''

That is, when GRC is exposed outdoors for a long period of time, its performance tends to decrease.

Methods for improving the durability of GRC include: ■ Using low-alkaline cement as a matrix (substrate, parent tissue).

■ Method of mixing deterioration inhibitor into the matrix.

■　Method to improve the alkali resistance of glass fiber.

■ Covering GRC 1! ! A method to prevent moisture from penetrating into the GRC.

and so on.

Although method (2) has the effect of slightly slowing down the deterioration rate, it is insufficient. The reason for this is that the reaction between cement and water produces alkali such as hydroxide, which inevitably corrodes glass fibers even if the amount is low.

In method (2), the deterioration inhibitor has the effect of neutralizing the alkali and protecting the glass fibers, but the conventionally accepted amount of addition is completely insufficient, and if too much is added, sufficient initial strength is not achieved. There are disadvantages that cannot be obtained.

Regarding (①), it is possible to use carbon fiber, but it is currently not viable due to the cost.

Regarding ■, there are also problems in terms of cost and effectiveness, and like ■, future research is needed. There is one question.

The above-mentioned mixed cementitious material (2) is the result of a successful combination of the above methods (1) and (2).

Therefore, the object of the present invention is to provide a mixed cementitious material which has durability comparable to that of the mixed cementitious materials (1) and (2) and which is sufficiently low in product cost.

The mixed cementitious material according to the present invention contains approximately SO or go% by weight of an admixture of at least one of ply ash, volcanic ash, clay, clay, 7-liquor powder and glass powder to cement; The method is characterized in that the blast furnace slag powder is mixed in an amount of about 1 to 10% by weight, and the cement is mixed in an amount of at least about 5% by weight.

Further, the mixed cementitious material according to the second invention contains about 50 or more admixtures by weight of at least seven types of admixtures among fly ash, volcanic ash, white clay, clay, silica powder, and glass powder. Aggregate, water, and alkali-resistant mixed cementitious material are mixed with about 0% blast furnace slag powder, S to 0% by weight, and at least about 5% by weight of the cement F. It is characterized by being mixed with glass fiber.

[Meaning of one leaf] (7) “Cement” refers to not only commercially available Portland cement but also low-alkali cement IQ jet cement (
Product name. Sumitomo Onoda Cement), T8mu Cement (
same. It also includes Osaka Cement), VHIC Cement (also known as Nippon Cement), and Alumina Seven Knots.

(b) "Ply ash" is commercially available lime ash that is mainly produced by separation from coal combustion waste gas at thermal power plants, etc.

(1) "Blast furnace slag powder" refers to a pulverized slag obtained by rapidly cooling blast furnace slag, which is a by-product during steel production, and has latent hydraulic properties.

In the case of the second invention, the mixing ratio of the alkali-resistant glass fiber is preferably about 10% by weight.

The prior invention related to (2) mentioned above adds fire ash, etc. in an amount that far exceeds the standard addition amount of conventional fly ash, and significantly improves the durability of GRC while maintaining the required strength. On the other hand, in the present invention, similar to the previous invention, the present invention, like the previous invention, adds a large amount of jO to 10%, and further replaces the remaining part with blast furnace slag powder to form cement. It has special features that reduce usage and provide the required strength and durability. Incidentally, by mixing only cement and blast furnace slag powder, little improvement in GRC durability can be expected.

As described above, according to the present invention, in addition to (a) adding a large amount of 7 rye sugar, etc., (b) adding a considerably large amount of easily available and inexpensive blast furnace slag powder, , (c) By reducing the amount of wax in cement, in particular, the cost required for expensive products such as jet cement is greatly reduced, and as a result of the above, it has durability that is comparable to that of the prior invention (1). However, it is possible to obtain a mixed cementitious material with a sufficiently low product cost.

[Reason for limited range]

If the admixture is less than about 10%, long-term strength deterioration of GRC cannot be prevented, and if it exceeds about 10%, there is insufficient room for mixing blast furnace slag powder and cement, making it difficult to harden sufficiently. 40-10% is preferred. If the blast furnace slag powder content is less than 5%, the cost reduction effect will be small, and if it exceeds 5%, there will be little room for mixing of admixtures, the effect of long-term strength deterioration will decrease, and the amount of cement mixed will be reduced, so it is not enough. It becomes difficult to harden.

20-35% is preferred.

If the cement content is less than 5%, it will take a long time to fully harden. 10% or more is preferable.

Also, among the admixtures, fly ash is particularly preferable because its particle shape is round, so even if a large amount is mixed, the mortar has good fluidity.

When using Portland cement as a cement, it hardens slowly when the mixing amount is less than 20%, and it takes a long time to develop strength, but it maintains high strength after sufficient curing. From the viewpoint of completing the curing in a short period of time, it is preferable to add a hardening accelerator such as Irwin to ordinary Portland cement, or to use a low-alkali cement having the constant hardness of jet cement as the cement.

〔data〕

■ A normal GRC plate completely deteriorates after being immersed in 70@C water for one day. For the GRC version according to the invention, 700
After being immersed in C water for 56 days (equivalent to 1+ o-so years of natural caster), it maintains almost its original performance.

■ When an eggplant-shaped weight with a power density of 4 is dropped from a height of 2 to 4 m, the GRC plate according to the present invention maintains its initial performance with only the part where the weight fell slightly dented. . On the other hand, in the case of the normal GRC version, even if it falls from a height of 20 pieces, it will be destroyed in a puff.

41 shows the results of a durability test of [Jet Cement] + [Blast Furnace Slag Powder] + (Fly Arts V Yu) system GRC accelerated in water at 70°C.

(a) Regarding the codes JC Nijitsu Cement BS: Blast Furnace Slag Powder (Product Name: Cement) FA: Fifty V Yu Eb: Flexural Young's Modulus (X104'Kf/d) IS: Izot Impact Strength (K4・am/cd) LOP: Bending proportional limit (Kf/m) MOR: Bending fracture strength (Kg/a
i) (B) GRC formulation W/C (water-cement ratio) 33% S/C (sand-cement ratio) O-6 Water reducing agent 50 N2. ! %/cement retarder (citric acid)'0.3%/cement sand; silica sand (produced in Seto) 5 for the above cement movrμ and cement mortar
% by weight of alkali-resistant gaffs and strands were simultaneously sprayed onto the formwork by a direct spray method, and cured for several weeks to obtain a GRC board with a thickness of /O.

The above GRC provisional was immersed in water at 70''C for a predetermined number of days to prepare a test specimen.

(c) Drop weight attack test specimen dimensions: aoo'y<guOO×IO-wax weight: eggplant 5 /KIF ◎:! A: No constant ○: Fine cracks on the back △: Amm cracks on the front and back of the clothing: Cracks #: Separately) Discussion (1) In the case of jet cement alone, when immersed in 70"C water for St days, the GRC will fall at the falling weight height / trout 1 brittle fracture in pieces.

(Experiment A/) (2) Jet cement inside 30-70% 0-
Even with 70% blast furnace slag, the durability of GRC hardly improves.

(Experiment Muda) (8) Put jet cement inside.

If it is replaced with %Fuuuuuuuu, the 1 # durability of GRC will be significantly improved.

(Experiment SS~1) (4) When jet cement is replaced with fly ash and blast furnace slag powder on the inside, the durability improves slightly when the fly ash is less than 4IO%, but when the falling weight height is Both will fall apart.

(Experiment AF~/Co) When the amount of fly ash is 40% or more at the mixing ratio according to the present invention, durability can be significantly improved even if the shet cement is replaced with blast furnace slag powder. (5
j! test &73~/r) i.e. 1. It is possible to use cheaper blast furnace slag powder and ply ash instead of the amount of jet cement used, which has a high luster, and is expected to significantly improve durability.

Claims (1)

[Claims] ■ For cement, at least about 10% by weight of admixture of fly ash, volcanic ash, white clay, clay, silica powder, and glass powder, and about 10% by weight of blast furnace slag powder. A blended cementitious material having a weight content of from about 10% to 4% and a content of at least about 3% by weight of said cement. (2) The mixed cementitious material according to claim 0, wherein the mixed phase material is only fly ash. ■ For cement, add at least 7 types of admixtures by weight of fluoride, volcanic ash, white clay, clay, silica powder, and glass powder to about 10% by weight, and about 10% by weight of blast furnace slag powder. , S or 40%, and the mixed cementitious material is mixed with aggregate, water, and alkali-resistant glass fibers, with the inner weight of the cement being at least about 5%. . (2) The mixed cementitious material according to claim 0, wherein the admixture is only Futuiatsu Vyu. ■ The mixing ratio of the alkali-resistant glass fiber is approximately by weight.
Mixed cementitious material according to claim 0, in which the content of the mixed cementitious material is between +/l and 40%.