JPH06298560A - Hydration heat inhibitor and method for suppressing hydration heat - Google Patents

Abstract

PURPOSE:To obtain a new hydration heat inhibitor for reducing rise in temperature caused by hydration heat generated during hardening of cement and a method for suppressing hydration heat using the inhibitor. CONSTITUTION:A hydration heat inhibitor contains a low-viscosity starch treated with an acid. The low-viscosity starch treated with an acid is gelatinized with warm water, cooled and kneaded with cement to suppress hydration heat.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat of hydration inhibitor and a heat of hydration suppression method, and more particularly to a novel heat of hydration inhibitor for reducing a temperature rise due to heat of hydration generated during hardening of cement. The present invention relates to a method for suppressing heat of hydration using the same.

[0002]

2. Description of the Related Art It is well known that when hardening concrete or mortar, the temperature rises due to the heat generated by the hydration reaction of cement.

This heat of hydration causes a considerable temperature difference between the outer circumference and the inside of the cured body,
Causes partial distortion and cracks in the cured product. After the temperature of the hardened body rises sharply, the stress when it falls causes defects such as thermal stress cracking in the hardened body. Cause problems such as. Such a problem becomes more serious as the size of the cured product increases.

Therefore, conventionally, various methods for preventing cracks and the like due to the heat of hydration have been studied and proposed. For example, reducing the amount of unit cement, using cement with a low heat of hydration, pre-cooling or pipe cooling the material, reducing the amount of one-time driving, providing a shrink joint, adjusting curing conditions, etc. A method has been proposed. There is also a method in which a heat of hydration inhibitor for preventing a temperature rise due to heat of hydration during hardening of cement is added to cement as an admixture.

[0005]

Among the above-mentioned conventional methods, except for the method using the heat of hydration inhibitor, all are subject to restrictions on material selection, construction method, conditions, etc., and their implementation is easy. Often not.

On the other hand, a method using a heat of hydration inhibitor can be carried out easily without any special restriction. Therefore, further research on such a heat of hydration inhibitor is carried out, and a new water Under the present circumstances, it is desired to develop a Japanese heat inhibitor.

The present invention has been made in view of the above conventional circumstances, and is a novel heat of hydration inhibitor for reducing a temperature rise due to heat of hydration generated during hardening of cement and hydration using the same. An object is to provide a heat suppression method.

[0008]

The heat of hydration inhibitor according to claim 1 is a heat of hydration inhibitor for preventing a temperature rise due to heat of hydration generated during hardening of cement, which comprises acid-treated low-viscosity starch. It is characterized by including.

The method for suppressing heat of hydration according to claim 2 is the method for suppressing heat of hydration, which comprises using the heat of hydration inhibitor according to claim 1 to prevent a temperature rise due to heat of hydration generated during hardening of cement, It is characterized in that the heat of hydration inhibitor is gelatinized with warm water and kneaded with cement.

The present invention will be described in detail below.

The heat of hydration inhibitor of the present invention contains acid-treated low-viscosity starch as an active ingredient. The acid-treated low-viscosity starch has a cold water-soluble content of 5% by weight or less and 25 wt. % Aqueous solution having a viscosity of about 25 cps is preferable. As such an acid-treated low-viscosity starch, a commercially available product can be used, and for example, "Rastergen" (trade name, manufactured by Nitto Kagaku Co., Ltd.) and other pregelatinized starch can be used.

The heat of hydration inhibitor of the present invention may contain an AE water reducing agent such as lignin sulfonate and a high performance water reducing agent such as naphthalene sulfonic acid condensate in addition to the acid-treated low-viscosity starch. good.

Since water-soluble starch has the best effect of suppressing heat of hydration when it is dissolved in warm water and used, in the method of the present invention, for example, acid-treated low-viscosity starch is used at about 50 to 80 ° C. After gelatinizing with warm water to a concentration of about 1 to 30% by weight, cold water is further added to prepare kneading water at about 10 to 40 ° C.
Mortar or concrete is kneaded using this kneading water. Alternatively, after water-soluble starch is gelatinized to the total amount of kneading water heated to about 50 to 80 ° C, this is cooled to 10 to 40 ° C.
The mortar or concrete is kneaded using this kneading water. It is preferable to use the acid-treated low-viscosity starch gelatinized with warm water after cooling by such a method.

If the amount of water-soluble starch to be added to the concrete or mortar is too small, the effect of suppressing the heat of hydration will not be obtained sufficiently, and if it is too large, the strength development will be impaired. 1 to 1.0% by weight
It is preferable to use the compounding ratio of.

[0015]

[Function] By adding a small amount of acid-treated low-viscosity starch, the effect of effectively preventing temperature rise due to heat of hydration of cement is exhibited.

Such water-soluble starch has good dispersibility by being gelatinized in warm water, and therefore, the best effect of suppressing heat of hydration can be obtained by cooling it and then kneading it with cement.

[0017]

EXAMPLES The present invention will be described in more detail with reference to the following examples.

Example 1 "Rastergen" was used as the water-soluble starch and kneaded in the following composition to cast mortar at ambient temperature 3
A simple adiabatic temperature rise test was conducted at 5 ° C, and the results are shown in Fig. 1.

For comparison, the same procedure was carried out for the case where no rastergen was added, and the results are shown in FIG.

Mortar mixed cement (ordinary Portland cement manufactured by Mitsubishi Materials Corp.): 1000 g Fine aggregate (No. 6 sand): 1500 g Water: 500 g Rastergen: 0.5% by weight relative to cement Addition of rastergen Is 100 warm water of 60 ℃ in advance
A predetermined amount of rastergen was dissolved in g, and cold water was added to this to obtain kneading water (35 ° C.) in which 500 g of water was dissolved in the rastergen, and kneading was performed using this kneading water.

Example 2 In Example 1, the content of the rasterogen was 0.25% by weight or 0.50% by weight with respect to the cement in the combination of 1500 g of cement, 1000 g of fine aggregate and 600 g of water. A simple adiabatic temperature rise test was performed at a temperature of 20 ° C., and the results are shown in FIG.

For comparison, the same procedure was performed for the case where no rastergen was added, and the results are shown in FIG.

From FIGS. 1 and 2, it is clear that the temperature rise due to the heat of hydration is effectively prevented by blending the acid-treated low-viscosity starch.

[0024]

As described in detail above, according to the heat of hydration inhibitor and the heat of hydration suppression method of the present invention, a temperature rise due to heat of hydration during hardening of cement is effectively prevented, and a cured product is obtained. It is possible to effectively prevent defects such as cracks.

[Brief description of drawings]

FIG. 1 is a graph showing the results of Example 1.

FIG. 2 is a graph showing the results of Example 2.

Claims (2)

[Claims] 1. A heat of hydration inhibitor for preventing a temperature rise due to heat of hydration generated during hardening of cement, wherein the heat of hydration inhibitor contains acid-treated low-viscosity starch. 2. A method for suppressing heat of hydration, which comprises using the heat of hydration inhibitor according to claim 1 to prevent a temperature rise due to heat of hydration generated during hardening of cement, wherein the heat of hydration inhibitor is hot water. A method for suppressing heat of hydration, which comprises gelatinizing and kneading with cement.