JPS6018616B2 - Hydraulic cement composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic cement formulation, that is, a hydraulic cement composition whose properties are improved by adding oligosaccharides that have been subjected to a specific treatment to cement paste, mortar, concrete, etc. It is related to.

More specifically, it relates to a hydraulic cement composition in which an oligosaccharide whose molecular weight is in the oligo region is treated with a terminal aldehyde group (reducing group) converted into a carboxyl group by an appropriate method and is mixed into a hydraulic cement. . Cement is the most important material for mortar, concrete, etc.

Many types of cement admixtures have been researched and are actually used for the purpose of improving the workability of mortar and concrete work, as well as improving the strength, water permeability, and other physical properties of mortar and concrete after construction. It's coming. Among the admixtures used for various purposes, water reducers are the most commonly used. It is widely recognized that the strength of mortar or cocrete after hardening is improved by adding a water reducing agent to reduce the amount of water added during mortar or concrete construction. Conventionally, as cement water reducing agents, lignin sulfonate, gluconate, sodium naphthalene sulfonate/formalin high condensate, polysaccharide, calcium chloride, triethanolamine combination composition, etc. have been used.

Some lignin sulfonates are obtained from the sulfite pulp manufacturing process, but their water-reducing effects vary, they have curing retardation, they increase the amount of air entrained, and they have a negative effect on the physical properties of mortar or concrete. There are disadvantages such as giving. Furthermore, gluconate exhibits significant curing retardation when added in a large amount, which poses a major problem in terms of utilization. The formalin condensate of sodium naphthalene sulfonate does not have a significant curing retardation effect even when added at a high concentration and exhibits a strong water reduction effect, but the water reduction effect is extremely weak when added at a low concentration level. Generally, its water reduction effect is inferior to that of gluconate. As a borisaccharide-based cement admixture, hydrolyzed starch with an average degree of glucose polymerization of 3 to 25 is known (Japanese Patent Publication No. 12436/1973), and some are commercially available, but when used alone, the hardening delay exceeds the allowable range. Because of its properties, it is usually used in combination with calcium chloride and water-soluble amines.

However, calcium chloride is harmful in terms of rust prevention of reinforcing bars in reinforced concrete, and has the disadvantage of accelerating cracking especially when drying shrinkage cracks occur in hardened cement.

Moreover, in this case, the compressive strength improves, but the bending strength conversely decreases. There has been a demand for an admixture that has a large water-reducing effect at a low addition level and has low curing retardation, but no conventional water-reducing agent has been able to satisfy this requirement.

In view of this, the present inventors have conducted numerous studies on the hardening retardation properties of cement, and have found that by using oligosaccharide oxides in which the terminal aldehyde groups of oligosaccharides are changed into carboxyl groups by an appropriate method, they are effective against cement retardation. It exhibits unprecedented water reduction properties at a low addition rate, not only increasing compressive strength but also improving bending strength.Furthermore, the amount of air entrained is small, the density is high, aggregate does not separate, and fluidity is increased. The present inventors have discovered that they have excellent effects such as improved performance and no significant curing delay even without the use of a curing accelerator such as calcium chloride, and have completed the present invention. That is, the present invention provides hydraulic cement with an average molecular weight of 300 to
The present invention provides a hydraulic cement composition comprising an oxide of 3,500 oligosaccharides mixed therein.

The oligosaccharide oxide of the present invention can be obtained by oxidizing an oligosaccharide having an average molecular weight of 300 to 3,500 obtained by hydrolyzing a polysaccharide, preferably starch, cellulose, or hemicellulose. Starch is a long chain molecule of glucose linked by Q-glucoside bonds.
Easily hydrolyzed by enzymes, nutrient acid, post-acid, etc.

The starch used in the present invention may be starch derived from any plant source. In addition, cellulose is composed of 8-glucosidic bonds of glucose, and since this bond is cleaved by an acid catalyst like a general acetal bond, the cellulose molecule can be easily hydrolyzed by an acid catalyst. Hemicellulose exists in wood and other lignified tissues together with cellulose, lignin, etc., and while it is easily soluble in alkaline solutions, it is relatively easily hydrolyzed by acids. The bases constituting hemicellulose include D-glucose, D-mannose, D-galactose, D-bractose, D-xylose, L-arabinose, D-glucuronic acid, D-galactronic acid, D-mannouronic acid, etc. Are known. The hydrolyzate thus obtained is autooxidized in the presence of an oxidation catalyst or oxidized with an oxidizing agent such as iodine to convert the terminal aldehyde group into a carboxyl group to obtain the oligosaccharide oxide of the present invention.
As described above, since oligosaccharide oxides are obtained by oxidizing the aldehyde group at the reducing end to a carboxyl group, they exist in the form of a hydrophilic salt or a hydrophilic carboxylic acid. Suitable water-soluble salts at this time include salts of Li, Na, K, Ca, Mg, NH4, alkanolamine morpholine, and the like. The oligo-bran oxide according to the present invention may be used as a cement additive, such as an air entraining agent, a cement wetting and dispersing agent, a waterproofing agent, a strength enhancer,
It can be used in combination with a curing accelerator and the like.

Hydraulic cements that can be used in carrying out the present invention include boltland cement, blast furnace cement, which are commonly used in cement, mortar, and concrete today.
These include silica cement, alumina cement, poppy, Moshi cement, trust cement, mineral cement, and rock ash cement. The oligosaccharide oxide of the present invention is 0.01% to 0.3% by weight, preferably 0.03 to 0.0% by weight based on cement.
．． It can be used by adding 25%.

The present invention will be explained in more detail below with reference to Reference Examples and Examples. Unless otherwise specified in the Examples, all parts and percentages are based on weight.

Furthermore, the present invention is not limited to the following examples. Reference Example 1 Production Example of Oligosaccharide Production of oligosaccharide from starch Corn, potato and tapioca were obtained by hydrolyzing using Q-amylase.

Production of oligosaccharides from cellulose Commercially available cellulose powder was mixed with HCI-QS04 (1:1
) It was obtained by dissolving it in a solution, treating it at 20°C for one hour, and then fractionating it with 0-95% acetone.

Production of oligosaccharides from hemicellulose Ground wood pulp was defatted with a concentrated solution of alcohol and benzene, delignified with sodium sulfite and bleaching powder, and treated with a 17.5% aqueous solution of caustic soda at 20°C.

After neutralization, hydrolysis was carried out for 45 minutes at 160-180 pm to obtain the desired product. Reference Example 2 Production Example of Oligosaccharide Oxide Oligosaccharide 2 obtained in Reference Example 1 was dissolved in a small amount of water (the aldehyde group content in the oligosaccharide was determined in advance by dilution with an iodine-alkaline aqueous solution (R.L.). Whistlereta】
．． , J. Research Nan Bur. SPn ship r
0.1N iodine aqueous solution and 0.1N
Add the caustic aqueous solution dropwise little by little.

After the addition was continued for 3 hours, the reaction mixture was poured into a large amount of methanol, and the resulting precipitate was repeatedly washed with 90% methanol until no reaction of iodide occurred, and then dried under reduced pressure to obtain the desired product. Ta. Example 1 Mortar test The non-additive (plain) mortar was conducted with the above standard mix, but in the additive-mixed system, the flow value was 1395 m/m (
Plain mortar f.

The amount of water and sand was adjusted to maintain a constant volume (one value). At this time, the addition ratio of all additives to cement was 0.10%, and the amount of air was 4 to 5%. Flow value, bending strength and compressive strength are according to JIS-R-5201, air amount is according to the gravimetric method in JIS-AIl16, and condensation time is A
The test was conducted according to the test method of STM C 403-61T. In addition, the molecular weight of the oligosaccharide was determined by vapor pressure osmosis method using an aqueous solvent using glucose as a standard substance. The results are shown in Table 1, and when gluconate, sorbitol, and oligosaccharide were added, a large degree of setting retardation was observed.

On the other hand, it can be seen that the Examples according to the present invention do not have a large setting retardation, and both bending strength and compressive strength are improved.

In addition, the admixture is abbreviated as follows.

Note) Starch hydrolyzate, calcium chloride, and water-soluble amine mixture () indicates the average molecular weight of oligosaccharides. Table 1 Example 2 (Molecular weight effect on performance as a cement admixture) A mortar test was conducted on the oxide (using a hydrolyzate) under the same conditions as in Example 1.

The results are shown in Table 2. Among the comparative examples in Table 2, those with short coagulation times (polymer oligosaccharide oxides) were inferior to those without additives in terms of water reduction rate and development of compressive strength.

It can also be seen that the low-molecular oligosaccharide oxides of the comparative examples have an abnormally long coagulation time, which is superior to those without additives in terms of both water-reducing properties and compressive strength. Example 3 (Influence of addition rate to cement) Except for changing only the addition rate to cement for oligosaccharide oxides obtained using oligosaccharides with an average molecular weight of 1100 (obtained by hydrolysis of starch) as raw materials. A mortar test was conducted under the same conditions as in Example 1.

The results are shown in Table 3. For comparison, a similar mortar test was conducted using oligo bran (starch hydrolyzate) having an average molecular weight of 1100 as a raw material while changing the addition ratio to cement. The results are shown in Table 4. Table 3 Table 4 Example 4 (Concrete test) o Material used: Cement Onoda ordinary boltland cement (specific gravity 3.
17) Tsumugi aggregate from Kino JII (specific gravity 2.6
0) Coarse aggregate Takarazuka crushed stone (maximum particle size 2 mounds) 2.62)
o Unit amount of cement 300k9/〆o Tsumugi bone material
45.0% o Measurement items and measurement method Slump value JISAIlOI Air content JISAIl16 Compressive strength JISAIl08 Curing time JISC403-61T o Additives and abbreviations used PL oligosaccharide oxide SO-OX (raw material: oligosaccharide obtained from starch, Mwn=900) Polysaccharide commercial product PS-C (mixture of oligosaccharide from starch, calcium chloride, and trietanoamine) oAir content 1.5-1.7% oWater-cement ratio 61% without additives 0Slump value Adjustment to 6.0 to 6.3 skin [Sand/gravel (with a fine aggregate ratio of 45%) was increased by the amount of water loss to keep the concrete volume constant] The results are shown in Table 5.

Table 5

Claims (1)

[Claims] 1. The average molecular weight of the hydraulic cement formulation is 300 to 35.
A hydraulic cement composition comprising an oxide of 0.00 oligosaccharide mixed therein. 2. The composition according to claim 1, wherein the oligosaccharide is a hydrolyzate of starch, cellulose, or hemicellulose.