JPS6219796B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention is an improvement of a cement for grout (hereinafter referred to as a cement for rapid hardening grout) containing a rapid hardening component consisting of calcium aluminate and gypsum and a highly active siliceous substance, and more specifically, a cement for rapid hardening grout. This invention relates to a rapidly hardening cement for grout that contains a polyalkylaryl sulfonate and a lignosulfonic acid-based cement dispersant to prevent breathing during construction and improve workability. It has good workability when grouting for fixing bridges on general roads and railways in cold regions or in need of emergency repairs, fixing anchor bolts to machine foundations, or repairing machine pedestals during downtime.
There is a need for a high-performance grout that does not cause breathing or settling and can reach a predetermined strength in a short period of time, and rapid hardening cement for grout containing calcium aluminate, gypsum, and silica has been proposed. However, due to the rapid hardening of this kind of cement for grouting, if the working time is incorrectly set, the mixer may harden before pouring, or in complex structures,
There were problems such as hardening before it was completely filled, and at low temperatures, there was not enough time to work unless hot water was used, and the initial strength was not achieved. In order to solve these problems, the inventors believe that
The present invention was achieved based on the knowledge that a polyalkylaryl sulfonate-based cement dispersant and a lignosulfonate-based cement dispersant may be used in combination. That is, in the present invention, in a rapidly hardening cement for grout, the weight ratio of the polyalkylaryl sulfonate cement dispersant to the lignin sulfonate cement dispersant is 1:1 to 3, and the total amount is calculated as the cement component. It is characterized by containing 0.1 to 1% by weight. The present invention will be explained in detail below. First, the cement for rapid hardening grout, which is the base material of the present invention, is a cement containing a rapid hardening component consisting of calcium aluminate and gypsum and a highly active siliceous substance for preventing breathing. , and a foaming agent such as metal aluminum powder, cement retarder such as citric acid, gluconic acid, tartaric acid, salts of these acids, etc., either singly or in combination. In the present invention, calcium aluminate is
Either crystallized or amorphous materials such as C ₁₂ A ₇ , CA, or C ₃ A may be used alone or in combination, but clinker may be heated and fired in a kiln and then rapidly cooled, or in an electric furnace. It melts,
Calcium aluminate is made by rapidly cooling this to become amorphous, and the molar ratio of the chemical components is CaO/Al ₂ O ₃ = 0.5 to 3, preferably 1 to 2.
It has extremely high reactivity and is therefore preferable. These calcium aluminates rapidly hydrate in the presence of lime and gypsum to form ettrin guides (3CaO・Al ₂ O ₃・3CaSO ₄・32H ₂ O), resulting in initial strength development and initial expansion development. Contribute to Cement generally has the defect of shrinkage during hardening and drying after hydration, but such a system that produces ettringite is effective in improving this defect. Next, as for the gypsum component, any of dihydrate, hemihydrate, and anhydrite may be used, but anhydrite is most desirable because it has less influence on setting. The blending amount is preferably 1 to 2 times the weight of the calcium aluminate, because such a ratio will ensure sufficient initial and long-term strength development. The fineness of the rapid hardening component consisting of calcium aluminate and gypsum is 3000 cm ² /g or more in Blaine value, preferably
4000 to 6000 cm ² /g, and it is preferable to mix this in 10 to 30% by weight based on the cement content of the cement for rapid hardening grout. %, long-term durability decreases. Suitable highly active silica substances include dust from the production of ferrosilicon, activated clay, or ultrafinely pulverized blast furnace slag.By blending these substances, the viscosity of the cement paste itself increases and breathing It is effective in preventing The powder degree is preferably 6000 cm ² /g or more. Further, the amount thereof is preferably about 1 to 10% by weight based on the cement content of the rapidly hardening cement for grout, but even if only this amount is added, breathing cannot be completely prevented. In other words, in order to prevent breathing using only highly active siliceous substances, it is necessary to use large quantities, but in this case, the workability and initial strength development of the grout will be adversely affected, so the amount of these substances used must be limited. There is. In order to improve this, in the present invention, specific amounts of two types of cement dispersants are used in combination. Portland cement is used as the cement component of the cement for rapid hardening grout, and specifically, in addition to ordinary Portland cement, early-strength Portland cement, medium-heat Portland cement, blast furnace cement, fly-ash cement, and sulfate-resistant cement are used. Examples include cement and silica cement. In addition, when adding a foaming agent, the amount added is 0.001 to the cement content of the cement for rapid hardening grout.
The amount is preferably 0.01% by weight. This makes it possible to prevent some surface settling due to curing shrinkage after implantation, and furthermore, by adding a cement retarder, workability becomes better. The amount of cement retarder added is preferably 0.1 to 1% by weight based on the cement content of the cement for rapid hardening grout. The present invention incorporates a polyalkylaryl sulfonate-based cement dispersant and a ligninsulfonate-based cement dispersant into a rapidly hardening cement for grout, thereby improving grout workability and breathing without impairing short-term strength development. It is intended to improve the In the cement dispersant, the ratio of polyalkylaryl sulfonate to lignin sulfonate is preferably 1:1 to 3 by weight. If the weight ratio of the lignin sulfonate cement dispersant to the polyalkylaryl sulfonate cement dispersant is less than 1, the number of air bubbles will increase, resulting in poor adhesive shear strength and impairing the appearance. If it exceeds this, the strength of the mortar will decrease significantly. The total amount of these dispersants is based on the cement content of the cement for rapid hardening grout.
It is blended in an amount of 0.1 to 1% by weight, but if it is less than 0.1% by weight, there will be no anti-breathing effect, and if it exceeds 1% by weight, material separation will occur and the properties of the grout will deteriorate, such as an increase in the number of bubbles. Commercial products of polyalkylaryl sulfonate-based cement dispersants include Kao Soap Co., Ltd.'s registered trademark "Mighty" and Takemoto Yushi Co., Ltd.'s trade name "Kyupol". Commercially available products include Sanyo Kokusaku Pulp Co., Ltd.'s registered trademarks "Sunflow" and "Sunextract", Nisso Master Builders Co., Ltd.'s registered trademark "Pozolith", etc. As explained above, the present invention is a conventional rapidly hardening cement for grout containing two specific types of cement dispersants, and the effects of the present invention are summarized as follows. (1) No breathing. (2) There is no flow down until setting begins, and even if setting starts, the fluidity can be restored by stirring and kneading, making it an extremely workable grout. can get. Therefore, there is no problem of hardening the mixer or causing filling defects. (3) Conventionally, when using low temperatures, it was not possible to secure working time without using hot water, but by using the product of the present invention, grouting can be easily carried out at cold temperatures without using hot water. The present invention will be further explained below with reference to Examples. Example The molar ratio of lime source and alumina source is CaO/Al ₂ O ₃
1.55 and melted it in an electric furnace.
To the amorphous calcium aluminate obtained by rapid cooling, a mixture containing 1.5 times the weight of insoluble anhydrite was pulverized to obtain a fineness of 5500 cm ² /g based on the Blaine value, and 20 parts by weight of the rapidly hardening component was added to the amorphous calcium aluminate. 4 parts by weight of "Denka Flower" registered trademark of Denki Kagaku Kogyo Co., Ltd. as activated siliceous material fine powder (blane 10000 cm ² /g or more);
75.5 parts by weight of ordinary Portland cement, 0.4 parts by weight of citric acid-based cement retarder, and 0.003 parts by weight of metal aluminum powder as a foaming agent were kept constant, and dispersants were added in varying proportions.
The polyalkylaryl sulfonate cement dispersant is Kao Soap Co., Ltd.'s registered trademark "Mighty", and the lignin sulfonate cement dispersant is Sanyo Kokusaku Pulp Co., Ltd.'s registered trademark "Sunflow", and the proportions are adjusted to 2. Shown in the table. Further, Table 1 shows the chemical components of the rapid hardening component consisting of calcium aluminate and gypsum.

【table】

[Table] 1000g of cement for this grout, 100g of natural sand
and 325g of water to make grout mortar,
Its physical properties were measured. The results at 20°C are shown in Table 3, and the results at 5°C are shown in Table 4. Experiment
Nos. 1, 2, 7, 8, 9, and 14 are the present invention and are experimental
Nos. 7 and 14 are cases where ultrafine granulated blast furnace slag was used instead of "Denka Flower".

【table】

[Table] In Experiment No. 12, when hot water at 45°C was used, the pot life was 20 minutes, the breathing rate was 0.2%, the sinking rate was -0.10%, and the compressive strength for 3 hours, 6 hours, and 1 day was, respectively. , 50Kg/cm ² , 100Kg/cm ² , and 210Kg/cm ² . The measured values in the table of Examples were determined by the following method. 1 Flow value (m/m) is based on JIS R-5201. 2 Breathing rate (%) is based on JIS A-1123. 3 Compressive strength (Kg/cm ² ) is based on JIS R-5201. 4 Settlement rate (%) is calculated by filling a stainless steel cylinder with a diameter of 5 cm and a height of 10 cm with mortar, immediately finishing the surface, and using a micrometer to measure the sinking of the mortar surface 24 hours after filling the mortar with the top of the mortar container as the zero point. The points were measured and the average sinking rate was determined.

Claims (1)

[Claims] 1 In a grouting cement containing a rapid hardening component consisting of calcium aluminate and gypsum and a highly active siliceous material, the weight ratio of polyalkylaryl sulfonate-based cement dispersant to lignin sulfonate-based cement dispersant is 1. A grouting cement containing 0.1 to 1% by weight of these components based on the cement content.