JPS5983968A - Concrete composition - 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 concrete composition characterized by containing an early-strengthening water reducer comprising a sulfonated melamine-formalin condensate, a water-soluble thiocyanate, or both of these and an alkanolamine. It is.

Adding a concrete composition during the production of concrete can reduce the amount of water required to obtain the same slump, and this can provide various improvement effects to concrete, so the use of water reducing agents is It is widely popular today. On the other hand, if the initial strength of concrete is high, the time required and period from pouring concrete into the formwork to when the formwork can be removed will be shorter, the formwork will rotate faster, and as a result, the construction period will be shortened. This brings about advantages such as reduction in construction costs.

Therefore, many early-strengthening water-reducing agents that have both water-reducing properties and early-strengthening properties are useful and are used in the industry.

By the way, in water reducing agents, the water reducing component (
For example, lignin sulfonate, oxycarboxylate, etc.)
generally has a delay property, which is undesirable in terms of initial strength development. Therefore, an early-strengthening component having early-strengthening properties is blended with these water-reducing components, thereby providing an early-strengthening liquid formulation having water-reducing properties and early-strengthening properties as a whole.

Traditionally, calcium chloride has been used as a toughening ingredient, but from the standpoint of preventing rust from forming on reinforcing steel in reinforced concrete, strict regulations have been placed on the amount of chloride mixed into concrete. For this reason, various restrictions have arisen in the use of early-strengthening liquid preparations containing calcium chloride. For this reason, so-called chloride-free early-strengthening water reducers have been proposed that contain early-strengthening ingredients other than calcium chloride (for example, diosulfate, calcium formate, and nitrite solutions); There was no satisfactory result in terms of strong pottery, and in practical terms there were interplants between the ridges.

In view of the current situation, the present invention was completed in the Song Dynasty as a result of various studies with the aim of providing a chloride-free, early-strengthening water reducer that is highly effective and highly practical.

That is, the present invention fd, an early strength-forming liquid formulation consisting of a sulfonated melamelamine formalin condensate (hereinafter abbreviated as SMF) and a water-soluble thiocyanate (hereinafter abbreviated as SON), is prepared such that SMF and SON are each 0.1. = Contain in an amount of 1% by weight and 0.03 to 0.2% by weight'ff: Provides a concrete composition with characteristics, and further contains alkanolamine in an amount of 0.005 to 0.2% by weight. The present invention provides a concrete composition characterized in that it is contained in an amount of 0.033% by weight.

The amount used above is expressed in terms of added weight based on cement in concrete.

The sulfonated melamine formalin condensate (SMF) used in the present invention is an admixture as described in Japanese Patent Publication No. 43-21659, and its schematic chemical structure is composed of six amine groups of melamine. It can be expressed as a condensate in which one of the amine groups is sulfomethylated and the remaining two amine groups are subjected to condensation with formalin. Depending on the condensation conditions, products of various molecular weights (that is, products of various aqueous viscosities) can be obtained, and blends 1 to 1 of these can also be used as appropriate. (For example, JP-A-157-
135760) The water-soluble thiocyanate (SON) used in the present invention is also called a rhodan salt, a sulfur cyanate, or a sulfur cyanide, and examples of the salt include an ammonium salt, an alkali salt, and an alkali metal salt. Appropriate. Still, SON
Industrial waste containing can also be used as the above SON. Such industrial waste includes, for example, industrial waste generated by processing methods (Fumax desulfurization method, Rodax cyanogen method) devised to remove cyanide hydrogen and hydrogen sulfide contained in coke oven gas.

The alkanolamine used in the present invention is a compound having a structure in which one to three aliphatic alcohols are bonded to a nitrogen atom (the bonds are carbon-nitrogen bonds), and generally an alkylene oxide is added to ammonia. Manufactured by Considering the availability, price, effectiveness, etc., it is preferable to use monoethanolamine, jetanolamine, triethanolamine, or a mixture of these two or filter components. Note that the high-boiling residue remaining after distilling off triethanolamine can also be used as a similar raw material.

Regarding surface active agents for concrete such as water reducers, quality standards are determined by the JASS 5T-401 Quality Standards for Surface Active Agents for Concrete described in JASEI5 Reinforced Concrete Work Standard Specifications for Building Works established by the Architectural Institute of Japan. However, in practice, the early-strength forming liquid preparation according to the present invention also meets this standard ((where it must pass, S
Regarding the amount of MF used, approximately 2% is the limit for passing this criterion. As for the amount of SMF used: As the usage amount exceeds 0.2 inch, the water reduction effect, strength, etc. increase, but when it exceeds 1%, these increasing effects tend to reach a plateau, and the rheology of concrete increases. Therefore, in the concrete composition of the present invention, the amount of SMF to be used is specified to be in the range of 0.1 to 1 part.

On the other hand, SCN itself exhibits an early-strengthening effect, but when used in combination with sMm, the synergistic I (early-strengthening effect) increases. It is significant in the range of 0.03 to 0.2%.

By the way, if the above-mentioned concrete composition of the present invention further contains alkanolamine in a dosage of 0.005 to 0.03%, the early strength effect will be further improved. Therefore, the present invention further provides a concrete composition having such a composition. When the amount of alkanolamine used is less than 0.005%, the improvement effect is insufficient, and even if it is more than 0.03%,
The effect reaches a plateau.

As described above, the present invention provides a chloride-free early-strengthening water-reducing agent that has excellent water-reducing effects and early-strengthening effects and is highly practical. The invention is based on the synergistic effect brought about by the combination of SMF and SCN or additionally alkanolamines.

Next, various embodiments of the present invention will be illustrated. A means for containing SMF%SON, alkanolamine, etc. in concrete within a predetermined content range may be to add each of these components separately to the composition, or by mixing these components into a single agent. It may also be added as a preparation. The most common method of addition is to add it at the time of mixing the concrete, but it is also possible to use the so-called post-addition method in which it is added after the mixing, and in some cases, it may be premixed into the concrete material before mixing. May be added. It is of course possible to use various other admixtures such as air-entraining agents and fly-a-thon in addition to each of these components.
cN.

It goes without saying that concrete compositions containing these various admixtures together with alkanolamines are included in the embodiments of the present invention.

Examples 1 to 18 This example shows concrete test results at a curing temperature of 20°C. Concrete tests were carried out in accordance with the JASEI 5 Standard Specifications for Building Works established by the Architectural Institute of Japan, [JASS 5 T-401 Quality Standards for Surface Active Agents for Concrete] for reinforced concrete construction. In other words, cement amount is 300 and 9/ln3 slump is 7.5c.
rn and cement amount 320 K9/m3 slump 18c
Tests were conducted at two levels of 1n, both with an air content of 4%.

The materials used were: ordinary Portland cement (mixed in equal amounts of 6 types of Onoda, Asano, and Sumitomo), the fine aggregate was Oi Ubukawa sand (FM = 2.79), and the coarse aggregate was Ome Ome. Crushed stone (MS=20mm, FM=.

The name "Melmento J" is used for water-soluble thiocyanate (S
Reagent grade sodium thioneanate was used as (!N)′, and technical triethanolamine (TEA) was used as the alkanolamine.

The results are shown in Tables 1 and 2 together with comparative examples.

Examples 19-62 This example shows all concrete tests at a curing temperature of 5°C. Concrete test method and materials used are the same as in Examples 1-18.

The test results are shown in Tables 6 and 4 along with comparative examples.

The symbols in the table are the same as in Examples 1-18.

Claims (1)

[Claims] 1. Contains 0.1 to 1% by weight of a sulfonated melamine formalin condensate and 0.03 to 0.2% by weight of a water-soluble thiocyanate based on cement in concrete. Concrete composition 2 containing 0.1 to 1% by weight of sulfonated melamine formalin condensate, 0.03 to 0.2% by weight of water-soluble thiophane salt, and 0.005 to 0% of alkanolamine, based on the cement in concrete. , 03% by weight of a concrete composition.