JPH0553741B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD The present invention relates to an underwater construction method for a cement mixture, which allows a good hardened product to be obtained without separation of materials in water. Conventionally, when constructing cement mixtures such as cement concrete and cement mortar underwater,
To prevent separation and dispersion of the cement mixture,
A method is known in which a water-soluble polymer admixture is added to increase the viscosity of the aqueous phase of the cement mixture. However, the addition of a water-soluble polymer admixture has the drawback that the strength and durability of the cement mixture cast in water decreases. In contrast, the method of the present invention provides a novel underwater construction method that does not use a water-soluble polymer mixture. That is, the method for underwater construction of a cement mixture according to the present invention involves adding and mixing a water-dispersible epoxy resin and its hardening agent to a cement mixture formed by mixing cement, aggregate, and water, and then adding and mixing a water-dispersible epoxy resin and its hardening agent. The gist of this invention is an underwater construction method for a cement mixture, which is characterized by increasing the viscosity of the cement mixture through a reaction, and then pouring it into water to harden it. The cements used in the present invention include Portland cement, ultra-rapid hardening Portland cement, jet cement, fly ash cement, blast furnace cement, silica cement, colloid cement, blast furnace colloid cement, alumina cement, and sulfuric acid-resistant cement. In addition to these cements, admixtures such as cement shrinkage compensators, hardening accelerators, hardening retarders, AE agents, dispersants, thickeners,
A foaming agent etc. can be used in combination. Aggregates include coarse aggregate, fine aggregate, filler, etc. Gravel, crushed stone, slag, and other artificial aggregates are used as the coarse aggregate. Fine aggregates include river sand, sea sand, mountain sand, silica sand, foundry sand, fine glass sand, crushed ceramic sand, crushed water sand, crushed ore sand, iron sand, whitebait, and artificial sand. Fillers include stone powder, pigments, carbon black, graphite, wood powder, cork powder, rubber powder, sawdust, inorganic fibers, natural organic fibers, synthetic fibers, carbon fibers, metal fibers, silicic acid powder, metal powder,
Such as metal oxide powder. As water, tap water, industrial water, groundwater, river/lake water, seawater, etc. are used, but fresh water is generally used. Water-dispersed epoxy resins are mainly composed of compounds that have one or more epoxy groups in one molecule, and are either epoxy resins that have been pre-divided into fine particles in water or epoxy resins that have self-dispersibility. It will be done. Self-dispersing products are those made by reacting epoxy resin with polybasic acid or its anhydride and neutralizing this with aqueous ammonia, amines, etc., or those made by adding a surfactant to this, or those made by adding a surfactant to epoxy resin. These include those that have been modified so that they can be dispersed in water by adding agents and other substances. The epoxy resin dispersed in water in the form of fine particles may also be one obtained by dispersing the epoxy resin in water using an emulsifier or the like immediately before use. Epoxy resins are most commonly condensates of bisphenol and epichlorohydrin. In addition, condensates of bisphenol and methyl epichlorohydrin or ethyl epichlorohydrin, condensates of these with dimer acids, dimer acid glycidyl ether, polyalkylene glycidyl ether, glycidyl ether of bisphenol alkylene oxide adducts, aliphatic glycidyl ether, urethane modification Bisphenol glycidyl ether, aliphatic aromatic co-condensed glycidyl ether,
Examples include glycidyl ethers such as vinyl cyclohexane dioxide, dicyclopentadiene oxide, and hydrogenated bisphenol. Furthermore, epoxy resins to which phenol, cresol, alkylphenol, salicylic acid, triphenyl phosphate, furfuryl alcohol, etc. are added are also used. Also, reactive diluents, pine oil, plasticizers,
Mineral oil, resin, resin acid, fatty acid, tall oil, bituminous material, etc. can also be added. The curing agent used in the present invention is mainly composed of a compound having a functional group that reacts with an epoxy group in one molecule. Specifically, a commonly known one is used. For example, aliphatic polyamines, aromatic polyamines, cycloaliphatic polyamines, aliphatic hydroxy polyamines, modified polyamines thereof, amine adducts thereof, polyamides, keteimines, tertiary amine imidazoles, BF ₃ amine complexes, acid anhydrides, Examples include dimer acid, trimer acid, and liquid polysulfide rubber. Among these, some preferred examples are diethylenetriamine, triethylenetetramine, tetraethylenebentamine, diethylaminopropylamine,
Aliphatic polyamines such as hexamethylene diamine, piperazine, N-aminoethylpiperazine,
Cycloaliphatic polyamines such as N-aminoethyl imidazoline, aliphatic hydroxyamines such as aminoethylethanolamine, monohydroxyethyldiethylenetriamine, phenylenediamine,
xylene diamine, dimethyldiphenylmethane,
Aromatic polyamines such as tridimethylaminoethylphenol and diaminodiphenylsulfone, dimer acids, trimer acids, polyamides produced by condensation of these acids with diamines or polyamines, modified amines thereof, and amine adducts, as described in Japanese Patent Publication No. 59-49247 These include water-dispersible imidazoline ring-containing amide compounds, and other polyamide compounds such as higher aliphatic diamines, triamines, and polyamines. These curing agents mentioned above are used alone or in combination of two or more. Among the hardening agents, those having water solubility or water dispersibility are used as they are, or in the form of an aqueous solution or dispersed in water.
A curing agent that is insoluble or non-dispersible in water is used after being dispersed in water using an appropriate surfactant, dispersant, acid, or the like. In the underwater construction method of the present invention, the composition of the cement mixture consisting of cement, aggregate, and water is as follows: general cement concrete, cement mortar,
It is based on the composition of cement paste, etc. The amount of water-dispersed epoxy resin and its curing agent added is generally 5 to 5 parts by weight per 100 parts by weight of cement as anhydride.
Used in a proportion of 100 parts by weight. The ratio of the epoxy resin and its curing agent is adjusted so that the respective functional groups involved in the reaction are equivalent or close to it. The cement mixture may be mixed using a suitable mixer such as a concrete mixer, cement mortar mixer, grout mixer, soil mixer, or bag mill mixer. The mixing order of the cement mixture of the present invention is that a water-dispersible epoxy resin and its curing agent are added to a cement mixture of cement, aggregate, and water, and the mixture is further mixed. There is then time for the initial reaction of the epoxy resin and its hardener to thicken the aqueous phase in the cement mixture before casting in water. During this time, the mixture may be continued to be mixed or left to stand, or may be mixed from time to time. You can easily determine whether a cement mixture that has thickened will separate or not by placing a portion of it in water. The time required for the epoxy resin to thicken due to the initial reaction varies depending on the temperature, type of material, and formulation, but is usually about 5 minutes to 60 minutes.
It takes about a minute. The aqueous phase of the cement mixture thickens;
When there is no longer any risk of separation or dispersion, pour in water. During casting, fluidity can be imparted by applying vibration to the cement mixture. Even when the cement mixture of the present invention is placed in water, there is no separation or dispersion of cement, aggregate, etc., so it can be placed densely. And, after being placed in water, it hardens well in water. In addition, it conforms well to the water bottom during pouring, and also has better bonding properties to surfaces that come into contact with the cement mixture, such as the water bottom and underwater structures, compared to products that do not contain epoxy resin and its curing agent. Furthermore, physical properties such as seawater resistance and chemical resistance of the cured product are also improved. Since no water-soluble polymer admixture is used, there is excellent curing, such as good physical properties of the product cured in water. Next, examples will be described. Example 1 Water-dispersible epoxy resin Ebicoat DX255 (Ciel Chemical Products, product Add and mix 50 parts by weight of main component bisphenol glycidiether (liquid anhydrous) and 50 parts by weight of a water-dispersible polyamide curing agent Ebikiure 3255 (Ciel Chemical Products, trade name liquid anhydrous). 10 minutes after mixing, fill the aquarium with water to a depth of 30 cm, and place a cylindrical mold with an open top (inner diameter 5 cm) inside.
cm, height 5 cm), and the cement mixture was dropped from a height of 1 m from the water bottom to fill the mold. The cement mixture cured well, with no material separation during filling and no water stains. The consistency of the cement mixture during underwater casting was measured by a flow test based on JIS R5201 cement physical test, and the flow table value was 15.5 cm. For comparison, a cement mixture of 100 parts by weight of early-strength Portland cement, 200 parts by weight of river sand, and 50 parts by weight of water was filled into an underwater formwork in the same manner as in the example.
The materials of the cement mixture were separated and dispersed in water, causing water stains, and no hardened cement mixture was obtained.

[Claims]

1 Consists of (a) 10-25% alkali metal aluminate, (b) 5-25% alkali metal carbonate, (c) 50-66% calcium aluminate, and (d) 5-13.8% aluminum sulfate. A quick-setting agent for cement characterized by: 2. The quick-setting agent for segments according to claim 1, wherein part of the calcium aluminate is replaced by quicklime and/or slaked lime within a range not exceeding 15%.