JPS6110047A - Cement dispersant - 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 [Field of Industrial Application] The present invention relates to a dispersant for cement or cement mixtures, and more particularly to a dispersant for cement mixtures; The present invention relates to a cement dispersant that enhances fluidity, prevents a decrease in fluidity over time, and improves workability.

[Conventional technology and problems]

Conventionally, cement compositions made by mixing cement, water, and optionally sand and gravel (1) dispersants have been found to undergo physical and chemical aggregation of cement particles over time after cross-contact, resulting in poor fluidity. Workability and workability deteriorate over time. For this reason, cement compositions have the disadvantage that their workable time (pot life) is limited. In addition, the cement mixture is often transported to the pouring site by an agitator vehicle (ready concrete mixer vehicle) after cross-tracking, and the time required for transportation varies greatly due to transportation route IIIA or traffic congestion.

For this reason, at the pouring site, it is extremely difficult to obtain consistent workability since each agitator car has different fluidity.

Furthermore, when pumping a cement mixture, if the pumping is temporarily interrupted during a lunch break or when changing stages, and then the pumping is attempted to be resumed, the fluidity of the cement mixture in the piping will decrease.

There are many problems such as sudden increase in pumping pressure or blockage when pumping is resumed.

In addition, in centrifugally compacted concrete or mortar, mixed*
*In many cases, centrifugal forming forms are filled with concrete, and centrifugal compaction is started once several forms have been filled. In this case, if it takes time to fill the formwork, the fluidity of the concrete decreases and centrifugal compaction becomes difficult.

For this reason, several methods have been devised to prevent the decline in fluidity of cement mixtures.

For example, to prevent chemical aggregation, oxycarbo/
There is a method of adding a curing retarder such as rR. Although this method can delay the aqueous phase reaction rf'i of cement, it is difficult to prevent physical agglomeration, and therefore it has not been possible to prevent slump loss. Also concrete,
There are disadvantages such as a decrease in the early strength of the mortar.

Also, a method of preventing cisuran loss by granulating a concrete fluidizing agent such as β-N8F4) Melakin sulfone formalin condensate, adding it to concrete, etc., and gradually disposing of this granular fluidizing agent. (Japanese Unexamined Patent Publication No. 159929/1983). This method can prevent slump loss to a certain extent, but the granular fluidizing agent may remain locally in the concrete after hardening.
This results in drawbacks such as a decrease in strength and durability.

In addition, there is a method of maintaining the fluidity of concrete for a long time by adding a fluidizing agent such as β-N8F or melamine sulfonic acid formalin condensate to concrete etc. (Japanese Patent Publication No. 53-5692). Public bulletin). Although this method is effective as a method for preventing slump loss, it is time-consuming to add the fluidizing agent, and the fluidizing agent is added in portions to concrete in bong pressure-feed piping and concrete in centrifugal compaction forms. Slump loss of concrete under difficult conditions cannot be prevented.

These conventional methods for preventing the decline in fluidity of cement mixtures have had at least eight problems, and have not been completely satisfactory.

[Means for solving problems]

The present inventors have arrived at the present invention as a result of intensive research to improve the drawbacks of the conventional methods described above.

That is, the present invention contains the following (al component and (b) component as essential components, and the (al component/(b) component N amount ratio is 9).
The present invention provides a cement dispersant characterized by a ratio of 0/10 to 99.9/0.1.

(IL) A formalin condensate of melamine having a sulfonic acid residue.

(b) A monohydric polymer having 1,500 or more oxyethylene groups and an average molecular weight of 80,000 or more.

The (+L) component of the present invention is known as a cement dispersant. Formalin condensates of melamine having sulfonic acid residues used in the present invention Formalin condensates of melamine having sulfonic acid residues are preferred; Cocondensates are also included. Carboxylated modifications of these may also be used.

Component (b) of the present invention includes polyoxyethylene,
Ethylene oxide adducts of compounds having active hydrogen are preferred. In this case, examples of compounds having active hydrogen include alcohols and amines. As the alcohol, (7) monohydric alcohols such as methanol and eq/l, and polyhydric alcohols such as ethylene glycol, propylene glycol, glycerin, sorbitol, sorbitol, and sucrose are used. As the amine, in addition to various monoamines, polyethylene diamine, triethylenetetramine, polyethyleneimine, etc. are used. As polyoxyethylene.

PKO-1, P'EO-3, Pico-8, PIEO-
No. 15 (both manufactured by Seitetsu Kagaku Co., Ltd.) and the like are good.

These compounds have more than 1500 oxyethylene groups,
Preferably F-J, having 5000 or more, average molecular weight 80
000 or more, preferably 150,000 or more.

(The Nfk ratio of the sJ acid component (b) component is 90710-99
,910.1, preferably 9515-99,8/0
, 2. If this ratio shifts to 90/10,
Since the dispersibility becomes extremely low, it requires a large amount to be added, is uneconomical, and has negative effects such as air entrainment and delayed setting. Moreover, when this ratio is larger than 99.970.1, slump retention becomes low.

The addition t of the cement dispersant of the present invention is 0.10% by weight of solid content with respect to the cement of the hydraulic cement composition.
~2.5 is good. If it is less than 0.10%, sufficient dispersion effect and slump loss prevention effect on cement particles cannot be obtained. Moreover, if it exceeds 2.5%, dispersion of the cicement particles, which is economically disadvantageous, becomes excessive, causing pleating and paste separation.

Is it most desirable to add the cement dispersant formulation according to the present invention to the hydraulic cement composition in the form of an aqueous solution, or is it effective to prevent slump loss even if components (a) and (b) are added separately? can be obtained. Also, the timing of its addition may include dissolving the compound in the mixing water, adding it at the same time as the mixing water, adding it to the mixed hydraulic cement composition, or adding it to the cement composition as a powder. is possible. Furthermore, it is also possible to add the dispersant of the present invention in portions at each stage.

In addition to the cement dispersant of the present invention, other cement dispersants, other water-soluble polymer compounds, etc. may be used. Other cement dispersants include ligninsulfonic acid, naphthalenesulfonic acid formalin condensate, polycarboxylic acids, and salts thereof. As a lignin sulfonate,
Ch6mical Admixtures for 0
onorete (M, R+RIXOM, E &
Pure gnosulfonat*, which has analytical values and properties similar to the molecular weight distribution as described on pages 5 to 9 of F, N, 5pan Ltd., is good.

[Examples and effects]

The present invention will be described below with reference to Examples. However, the present invention is not limited to these Examples. It's not something that can be added.

Examples 1 to 9, Comparative Examples 1 to 2 1) Concrete mix and materials used Table 1 □□□□ Cement (C) Ordinary Portland cement (Onoda Cement) Fine aggregate (S): Kino Yosan Sand (specific gravity 2.58, FM2
．． 91) Coarse aggregate (0): Crushed stone from Takarazuka (ratio i 2,61
, FM6.98) Water (Tsukasa: Yomighty AE-03 "Kao Soap C Co., Ltd.)" was added in an appropriate amount 2) Test conditions A mixing test was conducted into concrete using various cement dispersants shown in Table 2. Ta. In addition, the method for adding cement dispersant and mixing concrete *b is the following method 1 or 2.
It was done in one of the following ways.

Method 1: Dissolve the cement dispersant in lIl mixed water in advance, mix it in a tilting mixer at 25C to obtain the concrete shown in Table 1, and further increase the rotation speed to 2 rpm I/C. , continued for a predetermined time*b, and measured changes in slump and air amount over time. Measurements of slump, air content, compressive strength, and collection of strength specimens were all carried out in accordance with JIB.

Method 2: The same procedure as Method 1 was carried out except that the cement dispersant was added at the same time as the mixing water.

Table 2 (Note) ★1a-G Melamine sulfonic acid formalin condensed metal Na-salted salmon b-IPEO-1 (MW 150,000 to 400,000*) b-2
PE0-3 (MW 600,000 to 1,100,000 articles) b-3PE
Ethylene oxide (2580 mol) adduct of O-8 (MW 1.7 million to 2.2 million*) b-4PKI (polyethyleneimine, MY600) ★Catalog (Steel Chemical Industry) value vs. cement wt'A (solid content) 5) Test Results The test results are shown in Tables 5 and 4.

Table 3 (Note) Supper 1 Slump residual rate = (Slump after - hours) / (Initial slump) x 100 (%) Table 4 (Note) Table 1 Standard curing (ky/cIIF2) Table 3 and From the results in Table 4, it is clear that the product of the present invention has an extremely excellent effect in terms of slump survival rate (η).

Applicant's agent: Kaoru Furuya L 1), i-L -7-2 (Voluntary) December 28, 1980 [J

Claims (1)

[Scope of Claims] 1 Contains the following components (a) and (b) as essential components, and the weight ratio of component (a)/component (b) is 90/10.
A cement dispersant characterized in that the ratio is 99.9/0.1. (a) Formalin condensate of melamine having sulfonic acid residues (b) Water-soluble polymer compound 2 having 1,500 or more oxyethylene groups and having an average molecular weight of 80,000 or more (b) Component water-soluble polymer compound is polyamide The cement dispersant according to claim 1, which is oxyethylene.