JPS6041631B2 - Concrete workability improvement method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for improving the workability of concrete to which a superplasticizer is added.

In the present invention, concrete is a general term for mortar, concrete, etc. As is well known, among cement water reducing agents, dispersants, so-called high-performance agents, can impart high dispersibility without adversely affecting setting retardation or excessive air entrainment even when added to cement in large quantities. Water reducers are commonly used in the manufacture of concrete that requires high strength, especially concrete factory products such as piles, poles, and blocks. The drawback is that the flow and slump are significantly reduced, and it takes less time to work, especially at low temperatures.

The present invention solves these problems, and uses a very small amount of polyhydric phenols or a combination of these and sugars to prevent concrete flow and slump from decreasing and improves workability. We propose a method for improving the workability of concrete with additives added.

That is, in the present invention, 0.00% of polyhydric phenols are added to the cement content of concrete to which a high performance water reducing agent has been added.
5 to 0.3% by weight, or this and 0.005 to 0.1 saccharide
% by weight.

The present invention will be explained in detail below. In the present invention, the high performance water reducing agent has the properties described above, and specific examples thereof include naphthalene sulfonate formaldehyde condensate, naphthalene sulfonic acid and lignin sulfonic acid formaldehyde cocondensate, and melamine formaldehyde condensate. These commercially available products include Kao Soap Co., Ltd.'s product name "Mighty 10".
0", "Mighty 150", "Mighty HS", Takemoto Yushi Co., Ltd. product name "Pole Fine 5l0N", Sanyo Kokusaku Pulp Co., Ltd. product name "Sunflow PS", Pozolis Bussan Co., Ltd. product name "NL-" 1450”, “NL-4000”
, Showa Denko Co., Ltd.'s product name ``Melmento.''

Normally, these high-performance water reducers are added in an amount of about 0.2 to 3% by weight based on the cement content of concrete, but as mentioned above, concrete with these high-performance water reducers added has significantly lower flow and slump. Therefore, in the present invention, the cement content of concrete is 0.005~
A very small amount of polyhydric phenols of 0.0% by weight, or a very small amount of saccharide of 0.005 to 0.1% by weight is added together with these polyhydric phenols in order to further enhance the effect of the present invention. It is. Examples of polyhydric phenols include catechol, resorcinol, hydroquinone, pyrogallol, and phloroglucin.

The amount of this added is 0.0% relative to the cement content of concrete.
If it is less than 0.005% by weight, the effect of preventing a decrease in flow or slump will be small; When the slag weight exceeds %, the strength development is significantly delayed. The saccharide may be any polysaccharide such as monosaccharide, disaccharide, or trisaccharide, but saccharide is most preferable from the viewpoint of performance and economy.

Even when sugars are used alone without polyhydric phenols and at low temperatures, especially at temperatures below 15°C, they do not have the effect of preventing a decrease in flow or slump, but when used in combination with polyhydric phenols, Only then can the effect of preventing a drop in flow and slump be promoted. If the amount of sugar added is less than 0.005% by weight based on the cement content of concrete, there will be no promoting effect, and if it exceeds 0.1% by weight, curing will be significantly delayed, which is not preferable.

The present invention will be further explained below with reference to Examples.

Example 1 The product name "Mighty 150" was used as a high-performance water reducing agent, and it was fixed at 1.5% by weight based on the cement, and the type of polyhydric phenols and the amount added to the cement were changed, and mortar was prepared. The flow reduction was measured.

The mortar is ordinary Boltland cement, F. M2.9
5 natural river sand with a cement-to-sand ratio of 1:1.5. W
/C3O%, and the flow values were measured at a temperature of 10° C. immediately after kneading and 2 hours later. The results are shown in Table 1 as relative values when the flow value immediately after kneading is 100. Table 1 also shows the results of measuring the compressive strength after 7 days using the same mortar. Furthermore, experiment N
O. 1 is a comparative example. Table 1 shows that as the amount of polyhydric phenols added increases, the flow reduction prevention effect increases, and the development of strength at 7 days is delayed, but at 28 days of age, 740 to 750 kgIc expresses the strength of
It was confirmed that this value was almost the same as that without adding polyhydric phenols.

Example 2 Resorcinol was 0.03% by weight based on cement (however, no additive was used in Experiment Nos. 17, 18, 25 and 30),
A test was conducted in the same manner as in Example 1, except that the product name "Sunflow PS" was used as a high-performance water reducing agent at 1.5% by weight based on the cement, and the type of sugar and the amount added to the cement were changed. Summer.

The results are shown in Table 2. Experiment No. l7~19.25
and 30 are comparative examples. Table 2 shows that as the amount of added sugar increases, the amount of f. This shows that the effect of preventing low reduction becomes large and the development of strength at 7 days is delayed, but at 28 days of age, a strength of 740 to 750 k91c is developed, which is almost the same as that without adding sugars. It was confirmed that the value was

Example 3 As a high performance water reducing agent, the product name “Melment Fl” was used as a high performance water reducing agent.
The same test as in Example 2 was conducted except that O' was 1.0% by weight based on the cement.

The results are shown in Table 3. Experiment No. 35.36 and 4
Sample No. 1 is a comparative example in which resorcinol was not added. Table 3 shows that as the amount of sugar added increases, the flow reduction prevention effect increases and strength development at 7 days is delayed;
It was confirmed that this value was almost the same as that without the addition of sugars. Example 4 As a high-performance water reducing agent, the product name “Ball Fine 510N”
'', using the concrete formulation shown in Table 4, varying the resorcinol and sucrose, mixing 50f of concrete at a temperature of 8°C, and measuring the change in slump over time.

Claims (1)

[Claims] 1. Polyhydric phenols are added in an amount of 0.005 to 0.3% by weight based on the cement content of concrete added with a high performance water reducer.
Or a method for improving the workability of concrete containing a high-performance water reducing agent characterized by adding these and 0.005 to 0.1% by weight of sugars.