JPH0656549A - Cured body of cement having continuous open cells - Google Patents

Abstract

PURPOSE:To improve the adaptability to living of living beings by incorporating sand into paste prepd. with a specific org. material alone or a composite composed of this material and a pozzolan material, water, cement and chemical admixture, sticking this paste to aggregate and molding the mixture. CONSTITUTION:The paste having 20 to 150 poise viscosity is prepd. by adding and mixing 0.2 to 0.45 pt.wt. (hereafter pt.) water, 0.10 to 0.40 pt. org. material, such as high-polymer emulsion or cellulose system alone or composite composed of this material and pozzolan material, such as active SiO2 or active Al2O3, and 0.05 to 0.03 pt. chemical admixture, such as high-activity water-reducing agent or AE water-reducing agent to and with 1 pt. cement. The yield value of the paste is then increased by incorporating 0.2 to 0.8vol.% sand into the paste. The aggregate 2 having >=13 grain size and, if necessary, fibrous material 5 are incorporated into the sand-contg. paste 4 so that the paste 4 occupies 20 to 70% of the void volume of the aggregate 2, and thereafter, the paste is cured. The cured body of the cement contg. the solute of Ca(OH)2 in a lesser amt. and having the open cells 3 suitable for living of plants, microorganisms, small animals, etc., is obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hardened cement which has a small amount of Ca (OH) ₂ eluted and has continuous voids suitable for habitation of plants, microorganisms, small animals and the like.

[0002]

2. Description of the Related Art Conventional water-permeable concrete, when used (cured) in water, elutes Ca (OH) ₂ for a long period of time (for example, one year), and as a result, plants, microorganisms, small animals, etc. do not only live during that period. Durability was thereby significantly reduced. Further, when the particle size of the aggregate becomes large, it is necessary to increase the thickness of the paste to be attached to the aggregate from the viewpoint of strength, but there was a limit because only cement paste was used as the binder. On the other hand, when it is installed near the water where dry and wet are repeated, there is a problem in durability due to drying shrinkage of the paste.

[0003]

The present invention solves the above-mentioned conventional problems and prevents Ca (OH) ₂ from being eluted so that it is suitable for habitation of plants, microorganisms, small animals, etc. and purifies water by these organisms. The purpose of the present invention is to provide a hardened cement product having voids. Another object is to further improve the economical efficiency, strength and stability against drying by mixing sand with the cement paste. Further, a fibrous material is mixed or arranged to measure the increase in strength, and the above-mentioned object is achieved for a long period of time.

[0004]

Means for Solving the Problems In order to achieve the above objects, the present invention provides: Aggregate by mixing sand into a paste in which one or a composite of pozzolanic materials such as activated silica, activated alumina, fine slag powder, etc., and water, cement and a chemical admixture such as a high performance water reducing agent or an AE water reducing agent are mixed. 1. Hardened cement that is adhered to and molded Polymer emulsion (acrylic type, SBR type, vinyl acetate type, etc.) Cellulose type, acrylic type, or other organic material alone or a composite with the pozzolanic material is mixed with water, cement, and a chemical admixture such as a water reducing agent. Cement hardened body formed by admixing sand with paste and adhering to an aggregate 3.1 or 2 mixed fibrous material (metal, glass, carbon, boron, etc.) (length: 3 mm to 20 m)
m) or arranged (reticulate material) to further increase the strength.

[0005]

EXAMPLES The hardened cement product having continuous voids of the present invention will be described below. 1 and 2 show the hardened cement product of the present invention, and the hardened cement product (1) is manufactured by the following steps.

That is, in the first step, the total amount of pozzolanic material such as activated silica (SiO ₂ or Al ₂ O ₃ is 60%).
It is desirable to contain the above), water, cement and a high-performance water reducing agent (β-naphthalenesulfonic acid formalin condensate or the like) or an AE water reducing agent to form a paste. Here, it is desirable to use, as the pozzolanic material such as activated silica, a mixture of water in advance or a solution of SiO ₂ , Al ₂ O ₃ or the like.

Water: Cement = 0.20 to 0.45: 1
, Activated silica or pozzolanic material: cement = 0.
Adjust to 10 to 0.40: 1 (however, 0.20 to 0.70: 1 when using fine slag powder) and superplasticizer: cement = 0.05 to 0.03: 1. Activated silica in the above components reacts with Ca (OH) ₂ produced by hydration of cement components (C ₃ S, C ₂ S, etc.) to produce 1CaO.
mSiO ₂ · nH ₂ O-based compound and activated alumina are
Similarly, it reacts with Ca (OH) ₂ and 1CaO · mAl ₂ O ₃
It is intended to suppress the elution of Ca (OH) ₂ by generating an nH ₂ O-based compound and improve the strength of the hardened cement product (1) produced by densifying the paste film.
When steam curing or autoclave curing is performed, the above reaction rapidly progresses.

Therefore, the mixing ratio of the active silica or other pozzolanic substance should be within a certain range, for example, when it is small, it becomes difficult to suppress the elution of Ca (OH) _{2 and} the strength is sufficient. On the contrary, when the amount is large, the elution of Ca (OH) ₂ can be suppressed but the strength is rather lowered. The pozzolanic material such as activated silica, activated alumina, and fine slag powder may be replaced with a simple substance of an organic material such as a polymer emulsion or a composite material with the pozzolanic material.

Next, the high-performance water-reducing agent or the AE water-reducing agent in the above components is used for controlling the water: cement ratio to improve the strength of the hardened cement (1) and to adjust the viscosity of the paste. . The viscosity of this paste will affect the adhesion thickness to the aggregate (2), the formation of voids (3), etc. as described in the next step.
0 poise (apparent viscosity) is suitable. Then paste sand (preferably 50-300 μm) into the paste:
Sand = 1: 0.2-0.8 Vol. % Mix. As a result, the yield value of the paste containing sand is increased, and the thickness of the paste attached to the aggregate is further increased.

The second step is the step of adhering the sand-containing paste to aggregate (preferably crushed stone, slag, lightweight aggregate of 13 to 20 mm or more) (2) and hardening them. It is the process of making. The volume of this paste is such that 20 to 70% of the void volume of the aggregate (2) is filled.

This is for forming an appropriately continuous void (3) in the cement hardened body (1) produced, and therefore the amount of void (3) decreases as the amount of sand-containing paste increases. . The viscosity of the paste is also important, and when it is low, it becomes a liquid and drops from the aggregate (2). On the contrary, when it is high, it does not uniformly adhere to the surface of the aggregate (2).

Since the cement hardened product (1) uses a paste containing sand, it raises the apparent viscosity (especially the yield value) and is thickly adhered to the outer periphery of a relatively large aggregate of, for example, 13 mm or more, and does not separate and is uniform. A void is secured.

As a result, when used in water, not only microorganisms but also small animals and plants (for example, macroalgae with roots, reeds, etc.) can grow, which indirectly serves for water purification.

Detailed examples are as follows: (A) Activated silica by adjusting the water / cement ratio (W / C) to 0.30 and the activated silica / cement ratio (SF / C) to 0.25. Mortar (C: S = 1: 0.7 parts by weight) in which 100 to 200 μm sand (S) is mixed with a paste in which water, cement, and an appropriate amount of a superplasticizer are mixed.
Then, a cylindrical test piece of φ5 × 10 cm was prepared. 30 of these
After 28 days in water at ℃, the pH was measured by immersing in distilled water of 4 times the weight.

As a result of this experiment, Ca (OH) ₂ is 1CaO.
・ Compared with the one that does not mix activated silica and sand as mSiO ₂ · nH ₂ O-based compound, the amount of cement is relatively reduced.
The H value was reduced by 1.3, and it was found that the elution was suppressed. When slag fine powder was similarly used in a ratio of 0.4 to cement 1, the pH was lowered by 1.1. On the other hand, when the acrylic emulsion was similarly used at a ratio of 0.15 to cement 1, the pH was lowered by 1.0.

(B) Activated silica (0.2 parts by weight) containing 86% of SiO ₂ is dispersed in water (0.3 parts by weight), and further cement (1 part by weight) and a superplasticizer (0). ．
02 parts by weight) and sand (0.7 parts by weight) are added and mixed to obtain 1
A 20 poise (apparent viscosity) paste was made.

The paste (2 parts by weight) and crushed stone No. 5 (10
15 parts in diameter and 30 in height by mixing (part by weight) aggregate (2)
cm cylindrical specimen (for compression test) and cross section 10 x 10 cm
A 40 cm long prismatic specimen (for dry shrinkage test) was prepared. As a result of conducting a compressive strength test and a dry shrinkage test 56 days after this age, it was found that the dry shrinkage was 1.4 times as much as the strength of the general dusted cement hardening rest, and the dry shrinkage was reduced to 75%. Carbon fiber (10 mm length) was added to the above sand-containing paste in an amount of 5 Vol. %, The strength of the hardened cement product further increased by 1.2 times.

[0018]

The effects of the hardened cement product having continuous voids of the present invention are as follows. (1) The hardened cement product of the present invention has the structure described in the claims. Particularly, since the paste containing sand is used, even if a large aggregate is used, uniform large voids are secured and clogging is reduced. (2) The hardened cement product of the present invention has the same constitution as above, and in particular, it contains Ca (OH) ₂ elution because it contains an organic material such as activated silica or a pozzolanic substance or a composite material with a pozzolanic substance. Less plants, microbes,
Suitable for small animals. (3) The hardened cement product of the present invention has the same constitution as described above, and in particular, since the paste containing sand is adhered and hardened on the aggregate, homogeneous continuous voids are formed, so that plants, microorganisms,
Suitable for small animals. (4) The hardened cement product of the present invention has the same constitution as above, and in particular, because it is molded with unevenness both inside and outside, it accelerates the attachment or habitation of the above organisms and indirectly purifies water by passing through internal voids. To be done. (5) The hardened cement product of the present invention is economically economical because it contains sand, and has little drying shrinkage, and has high resistance to dryness and humidity. (6) The hardened cement of the present invention can further increase the strength by mixing or arranging a fibrous material.

[Brief description of drawings]

FIG. 1 is a perspective view of a hardened cement product of the present invention.

FIG. 2 Same as above Enlarged cross-sectional view of hardened cement

[Explanation of symbols]

 1 Cement hardened body 2 Aggregate 3 Void 4 Sand-containing paste 5 Fiber

Claims (3)

[Claims] 1. Sand is added to a paste in which one of a pozzolanic material such as activated silica, activated alumina, slag fine powder or a composite thereof and water, cement and a chemical admixture such as a high performance water reducing agent or an AE water reducing agent are mixed. Cement hardened body mixed and adhered to aggregate and molded 2. Sand is mixed with a paste in which a simple substance of an organic material such as a polymer emulsion, a cellulosic material, an acrylic material or a composite with the above pozzolanic material, and a chemical admixture such as water, cement and a water reducing agent are mixed. Hardened cement molded by adhering to aggregate 3. A cured product obtained by mixing or arranging a fibrous material with the cured product according to claim 1 or 2.