JPH0350146A - Mortar composition - Google Patents

Abstract

PURPOSE:To provide the material which is extremely good as a repair material for a concrete structural body and a substrate treating material for a waterproof material by specifying the combination of the raw materials in a system formed by incorporating a synthetic high-polymer emulsion into mortar. CONSTITUTION:This mortar compsn. consists, by weight %, of 20 to 40% ordinary Portland cement (a), 4 to 10% white Portland cement (6), 4 to 10% extra fast hardening cement (c), 20 to 60% aggregate (d), 3 to 5% synthetic high-polymer emulsion (resin solid) (e), and 5 to 20% water (f). The strength decreases if the ratio of the component (a) is too low and the rate of shrinkage increases if the ratio is too high. The strength decreases and the hardened body has a gray color if the ratio of the component (b) is too low and the rate of shrinkage increases if the ratio is too high. The initial strength decreases if the ratio of the component (c) is too low and the pot life is short and the hardened body has a brown color and has the easy tendency to cracking if the ratio thereof is too high. The rate of shrinkage increases if the ratio of the component (d) is too low and the strength decreases if the ratio is too high. The waterproof performance, adhesive strength and neutralization performance are insufficient if the ratio of the component (e) is too low. The strength development of the mortar delays and the workability degrades if the ratio thereof is too high.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application J] The present invention relates to a mortar composition for use as a repair material for concrete structures and as a ground preparation material for waterproofing materials in the field of civil engineering and construction.

[Prior Art] As mortar mainly based on cement, there are known sand mortar prepared on-site and a system in which a synthetic polymer emulsion is mixed into the sand mortar.

Furthermore, commercially prepared mortar and a system in which a synthetic polymer emulsion is mixed into this mortar are also known.

[Problem to be solved by the invention]

The above-mentioned mortar is used as a surface preparation material before applying waterproofing material, but it is especially used for filling wood concrete parts and parts of separators, and for filling unhealthy parts of concrete structures such as junkers, bean plates, and concrete pouring. It is not fully satisfactory as a mortar for filling joints, cracks, etc. after chiseling.

In these applications, the following performance is required.

■The construction thickness ranges from 2mm to 30mm.

■Good adhesion to the base cocrete frame.

■High waterproof performance.

■The color is the same as the underlying concrete structure.

■Fast development of strength (favorable as it shortens the process and there is no sagging during wall construction).

■Pot life is 15 minutes or more (if it is shorter than this time, work will be hindered).

However, none of the mortar to date has satisfied all of the above conditions (for example, there are problems such as poor waterproof performance, poor adhesive strength, and easy cracking).

[Means for Solving the Problems 1] In order to solve the above problems, the inventors of the present invention have discovered that a specific combination of mortar compositions containing synthetic polymer emulsions is excellent as a base treatment material for waterproofing materials. The present invention has been completed.

That is, the present invention includes (a) 20 to 40% by weight of ordinary Portland cement (
b) White Portland cement 4-10% by weight (c)
Mortar composition consisting of ultra-fast hardening cement 4-10% by weight (d) Aggregate 20-60% by weight (e) Synthetic polymer emulsion 3-5% by weight (resin solid content) (f) Water 5-20% by weight It is a thing.

Hereinafter, the configuration of the present invention will be explained in detail.

Contains cement, aggregate, synthetic polymer emulsion, and water as essential ingredients. Ordinary Portland cement is a typical cement known in the world, and its usage amount is 20 to 40% by weight.
If it is less than 0% by weight, the strength will drop significantly, and if it exceeds 40% by weight, the amount of shrinkage will increase and cracks will easily occur.

The basic performance of the white Portland cement used is not much different from ordinary Portland cement, but the decisive difference is the color tone of the hardened cement.

That is, ordinary Portland cement has a gray color, but white Portland cement has a white color and is therefore widely used as a decorative material and joint material for buildings that particularly require aesthetic appearance.

The amount used is preferably 4 to 10% by weight; if the amount of white cement is less than 4% by weight, the strength decreases and the color tone of the cured product becomes grayish. Moreover, if it exceeds 10% by weight, the color becomes close to white, but the amount of shrinkage increases.

The ultra-fast hardening cement used in the present invention is commercially available under the name Jet Cement, and is known as a cement that develops practical strength within 2 to 3 hours after water injection and mixing, and shows increased strength over a long period of time.

For this reason, jet cement is mainly used for construction work that requires urgent use of mortar and concrete.

This cement has 3 CaO・SiO++ as its main component,
In addition, 1lca04A120*, CaFz and Ca5
It is composed of O+, etc., and an example of typical chemical components is shown in Table 1.

Table 1 The amount used is preferably 4 to 10% by weight. If the amount of jet cement is less than 4% by weight, the initial strength will decrease and 1
If it exceeds 0% by weight, the strength will be improved, but the pot life will be very short, and the color of the cured product will be the color of jet cement, that is, brownish brown, which is aesthetically undesirable. Moreover, if it is added in excess, cracks are likely to occur.

The aggregate used for this material is usually 2 to 1 OIII
Generally, silica sand No. 3, No. 4, No. 5, No. 6, No. 7, No. 8, etc. is used for use with a thickness of +, but using No. 6 or less silica sand improves the surface condition of the hardened mortar. It is smooth and preferable.

The appropriate amount of aggregate to use is 20 to 60% by weight;
If it is less than 0% by weight, the strength will increase, but the amount of shrinkage will increase. The opposite is true when the content exceeds 60% by weight.

The synthetic polymer emulsion (resin solid content) is preferably 3 to 5% by weight, and if it is less than 3% by weight, waterproof performance, adhesive strength, and neutralization performance are insufficient.

However, if it exceeds 20% by weight, although the above performance is very good, the strength development of the mortar is delayed and workability during construction becomes poor.

Examples of polymer emulsions include acrylic polymer emulsions, vinyl acetate polymer emulsions, and SB.
Examples include R-based polymer emulsions, ethylene-vinyl acetate-based polymer emulsions, styrene-acrylic-based polymer emulsions, and epoxy resin-based polymer emulsions.

In the present invention, any of the above-mentioned polymer emulsions may be used, but SBR-based polymer emulsions are particularly preferred.

The amount of water added is adjusted according to the softness of the user's work, but since this material is a filling material, it will be a hard kneading.

Furthermore, it is more preferable to add a thickener such as methyl cellulose or silica hume, which is fine silica powder, to the composition, since this improves workability.

[Examples and comparative examples]

Examples and comparative examples will be described below to clarify the effects of the present invention, but the technical scope of the present invention is not limited thereto.

As Examples and Comparative Examples, Table 2 shows the compositions, test results, and evaluation results of the mortar tested.

The materials used are as follows.

Ordinary Portland cement: White Portland cement made by Onoda Cement: Super fast-hardening cement made by Onoda Cement
: Manufactured by Sumitomo Cement (product name: Jet Cement) SBR emulsion : Manufactured by Showa Denko (Petallus 5)
B300) Silica sand No. 6: Made in Kashima The evaluation items are pot life, color of cured product, adhesive strength test, water permeability test, bending compressive strength test, temperature 2
Measurement was carried out under conditions of 0°C, humidity and 65% RH.

The content of the test is as follows.

The hardened mortar that had been kneaded was left outdoors for 3 months and its color was observed.

The IJJL bending test was conducted in accordance with JIS A6909. Six types of materials were applied to a concrete sidewalk board (JIS A3304) to a thickness of 5 mm, and the adhesive strength was measured after 28 days.

E Mercury 1 The test was conducted in accordance with JIS A1404.

After curing for 21 days, the increase in water permeability was measured at a water pressure of 3 kg/crn'' and a pressurization time of 1 hour.

Increase in water permeability = W2-W.

Wl: Weight N (g) before conducting water permeability test W2 =
Weight (g) immediately after conducting the water permeability test. The test was carried out in accordance with JIS R5201.

The bending compressive strength was measured 5 hours, 1 day, 7 days, and 28 days after pouring.

On-site stratification At an actual site, six types of materials were filled into the wood-containing parts of a cocrete frame, and the occurrence of cracks was investigated after three months.

From the above results, it can be said that the product of the present invention has a well-balanced material in all respects compared to the comparative products (i.e., comparative products C and E).
Although the adhesive strength test and the water permeability test were good, and the initial strength (5 hours) was high, there were problems with the color and pot life of the cured product, and in particular, comparative product C showed cracks in the material filled in the wood concrete part. There has occurred.

In addition, the comparative product has good pot life, color of cured product, adhesive strength test, and water permeability test, but the initial strength (5 hours) is very low and cannot be measured. A crack appeared on the item.

Furthermore, Comparative Product F has good color of the cured product, adhesive strength test, and field test, but has a rather short pot life, poor water permeability test, and low initial strength (5 hours) and long-term strength.

〔Effect of the invention〕

The mortar composition of the present invention has a long pot life, the color of the cured product is close to the color of the concrete frame, high adhesive strength and bending compressive strength, and excellent waterproof performance, so it is suitable for civil engineering and l...
It is an extremely excellent material as a repair material for concrete structures and as a base treatment material for waterproofing materials in the field of canning.

Claims (1)

[Claims] (a) 20-40% by weight of ordinary Portland cement (b) 4-10% by weight of white portland cement (c) 4-10% by weight of ultra-fast hardening cement (d) 20-60% by weight of aggregate ( A mortar composition comprising (e) 3 to 5% by weight of a synthetic polymer emulsion (resin solid content) and (f) 5 to 20% by weight of water.