JPH0818858B2 - Manufacturing method of fiber reinforced cement products - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing fiber reinforced cement products.

[0002]

2. Description of the Related Art Asbestos is useful and widely known as a fiber used in fiber-reinforced cement products. However, since asbestos causes pollution, it is strongly requested to limit its use or completely abolish it, and various proposals have been made to use pulp fiber as a substitute fiber. Furthermore, since waste paper pulp can be used for this pulp fiber, the use of various waste paper pulp has been studied from the viewpoint of effective utilization of resources.

[0003]

However, the waste paper pulp, which is a recovery resource, contains a large amount of sugars that inhibit the hardening and binding reaction of cement, and therefore the step of removing the sugars is required when using waste paper pulp. For example, as a method of removing sugars,
A method is known in which waste paper pulp and water are mixed, and after sufficient stirring, water is filtered to dissolve and remove sugars, and this is added to a cement mixture as a pulp raw material and mixed to form a shaped body (for example, a special method). Wishhei 1-82539).

However, the above method has a problem in that it requires a step of adding water to the waste paper pulp and mixing, and a step of filtering and drying the mixed pulp, which requires considerable time and labor.

[0005]

SUMMARY OF THE INVENTION In view of the above problems, the present invention has sufficient strength without causing a reduction in strength even if the waste paper pulp contains a large amount of sugars without extracting and removing the contained sugars with water. The purpose of the present invention is to provide a method for producing a fiber-reinforced cement product that can be expected to exhibit strength.

[0006]

That is, the method for producing a fiber-reinforced cement product of the present invention is a method for producing a cement composition containing cement, a silica component, and a waste paper pulp, a lightweight aggregate, an extrusion aid and the like as a reinforcing fiber with water. In the method for producing a fiber reinforced cement product, which is formed by adding and kneading,
It is characterized in that 1 to 5% by weight of rhodan calcium dissolved and mixed in the added water is contained in a solid conversion ratio with respect to 100% by weight of cement.

[0007]

In the present invention, the fact that the pulp, or the waste paper pulp is used as the cement, the silica content, and the reinforcing fiber is known as a so-called asbestos-free cement mixture, and there is no particular description. In this invention, rhodan calcium is used as a means for removing sugars from the waste paper pulp.

The main component of calcium rhodanide is calcium thiocyanate. Calcium thiocyanate is highly reactive and has the effect of promoting the hardening reaction of cement.
On the other hand, since it has an effect as a bactericidal agent and an antioxidant on organic substances, polysaccharides such as starch contained in the waste paper pulp, which is a natural organic fiber, reacts with an enzyme that promotes hydrolysis,
Alternatively, it can be expected to prevent deterioration due to oxidation and decomposition of waste paper pulp due to its antioxidant effect.

The above rhodan calcium is contained in an amount of 1 to 5% by weight based on 100% by weight of cement in terms of solid conversion.
This is because if it is less than 1% by weight, the effect of preventing hardening damage due to saccharides is poor, and if it is more than 5% by weight, it is less effective for the addition and economically disadvantageous. In addition, general pulp can also be used as the reinforcing fiber used.

[0010]

Embodiments of the present invention will be described below. As waste paper pulp, recovered pulp from office envelopes, in which starchy polysaccharides were confirmed by the iodine-starch reaction under the influence of the "glue" of the envelope, and as rhodan calcium, calcium thiocyanate 34.5%, thiosulfate Calcium 0.49
%, PH 7.6% were prepared, cement, silica sand, waste paper pulp and methyl cellulose shown in the upper part of Table 1 were mixed, and water and rhodan calcium (outer percentage) in the proportions shown in Table 1 were added and kneaded. The rhodan calcium used was dissolved in kneading addition water, and the kneading water ratio was reduced by the same amount as the mixing amount, and water was added.

Then, using an extruder, the thickness is 2 cm and the width is 25 cm.
The sheet material was extruded and naturally cured at a temperature of 30 ° C. and a humidity of 90% for 24 hours, and then autoclaved at a pressure of 8 kg / cm ² for 8 hours. A strength test based on JIS No. 4 was performed on the obtained sample. The bending strength test results are shown in the lower column of Table 1.

[0012]

[0013]

Industrial Applicability As described above, the present invention requires a step of removing impurities regardless of whether waste paper pulp containing sugars or recovered paper has a wide range of quality. It can be used as it is. Since rhodan calcium, which is highly reactive, is used, it can accelerate the hardening reaction of cement and exhibit the effect as a reinforcing fiber for waste paper.

Claims (1)

[Claims] 1. A method for producing a fiber-reinforced cement product, which comprises adding cement to a cement composition containing a waste paper pulp, a lightweight aggregate, an extrusion aid and the like as a cement component, a silica component and a reinforcing fiber, and kneading the mixture to form a shape. In the above, the rhodan calcium dissolved and mixed in the above-mentioned added water is the solid conversion ratio of 100% cement.
A method for producing a fiber-reinforced cement product, characterized by containing 1 to 5% by weight with respect to% by weight.