JPS61163158A - Cement dispersion - 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 [Industrial Field of Application] The present invention relates to a cement dispersant, and more particularly to a cement dispersant for concrete and mortar that improves the surface appearance of the product.

[Conventional technology]

Traditionally, precast concrete products are produced by injecting a cement-containing material, such as a mixture of cement, sand, gravel, water, etc., into a formwork, and then using an internal or external vibrator to drive out voids from the cement-containing material in the formwork. A construction method is used in which the formwork is filled to the closest density. In addition, in order to obtain a high-strength product,
Maintains the fluidity of cement-containing substances even if the unit water volume is reduced,
High-performance water reducing agents that can improve filling properties due to vibration are generally used.

[Problem that the invention seeks to solve]

However, with the above method, large voids can be removed by vibration, but small air bubbles may remain between the formwork and the concrete product, or part of the product may adhere to the formwork, causing the concrete product to be damaged. The aesthetic appearance of the surface is extremely poor. In addition, as a method to improve these problems, it is common practice to apply mineral oil or the like as a mold release agent to the formwork side, but this is suitable for improving the releasability between the concrete product and the formwork. , is still insufficient to eliminate air bubbles on the concrete surface.

[Means for solving problems]

The present inventors conducted extensive research to improve the drawbacks of the concrete products mentioned above, and found that a specific anionic surfactant that can lower the surface tension of cement-containing substances and has low foaming properties was used as a specific high-performance water reducing agent. It has been found that by combining these two methods, air bubbles on the surface of concrete products can be eliminated and the aesthetics can be significantly improved.

That is, the present invention adds dialkyl sulfosuccinate to the sulfonate of melamine-formalin condensate by weight from 0.1 to 1.
The object of the present invention is to provide a cement dispersant characterized in that it contains 0%.

Cement-containing substances such as concrete and mortar to which the cement dispersant of the present invention has been added have a reduced surface tension, so they have a good affinity with mineral oils applied to the formwork surface. It is believed that the small air bubbles on the top replace the cement-containing material and migrate inside, thereby eliminating the drawbacks of the prior art.

The dialkyl sulfosuccinate (alkyl is a saturated or unsaturated alkyl group having 6 to 18 carbon atoms, the salt is an alkali metal salt or ammonium salt) which is an anionic surfactant used in the present invention includes sodium dioctyl sulfosuccinate (Perex OTP). Kao soap cracker (trade name) etc. are effective, and are excellent because they lower the surface tension of cement-containing substances when added in small amounts and have low foaming properties.

Furthermore, the sulfonate salt (alkali metal salt or ammonium salt) of a melamine-formalin condensate, which is a high-performance water reducing agent used in the present invention, is effective as it does not impair the performance of the surfactant. On the other hand, formalin condensates of .beta.-naphthalene sulfonic acid and creosote oil sulfonic acid, which are known as high performance water reducing agents, tend to deteriorate the performance of the surfactant and are therefore not preferred.

The composition of the dispersant of the present invention is such that 0.1 to 10% by weight of dialkyl sulfosuccinate is added to the sulfonate of melamine-formalin condensate, and optimally 1 to 10% by weight is added.
It is 5%. If the amount added is lower than this, the effect of improving the surface appearance is small, and if the amount added is higher than this, the amount of air entrained increases, which is undesirable.

〔Example〕

Next, the present invention will be explained with reference to Examples, but the present invention is not limited to these Examples.Example Sodium sulfonate (Melmen) of melamine-formalin condensate? -10 (manufactured by Showa Denko) and sodium dioctyl sulfosuccinate (Perex OTP, manufactured by Kao Soap) (Table 1), concrete was mixed with the composition shown in Table 2, and then slumped. and measured the amount of air. φ11 was then coated with mineral oil as a mold release agent.
A 0x20 cylindrical form was filled with concrete, and vibratory filling was performed for 15 seconds using a table vibrator to form a specimen. The results are shown in Table-3.

Table-3 This standard curing σ2. (28-day strength) *The number of bubbles with a diameter of 1 mm or more on the surface of this concrete is 1
The surface aesthetics was determined by counting the area of 000e'' as follows.

Less than 5 pieces 205 to 20 pieces: Δ 20 pieces or more: × Clearly, according to the product of the present invention, the surface appearance is improved without increasing the amount of air and without affecting the compressive strength.

Claims (1)

[Claims] A cement dispersant comprising a dialkyl sulfosuccinate added in an amount of 0.1 to 10% by weight to a sulfonate of a melamine-formalin condensate.