JPH1192250A - Production of hardened mortar product and mortar - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a hardened mortar product, capable of improving the water permeability to be a factor causing the deterioration in the mortar and maintaining the water repellency at the initial execution and having a great resisting power even for chemical and physical erosion or the like. SOLUTION: This hardened mortar product is obtained by compounding a substrate containing a cement mixed with an aggregate or a pigment or the like with a powdery thermoplastic resin in an amount of preferably about 5-30 wt.% based on the cement, providing a mortar, placing the resultant mortar, curing the placed mortar for a prescribed period, hardening the cured mortar and then heating the hardened product at a temperature for enabling the thermoplastic resin to melt. The powdery thermoplastic resin is uniformly diffused and mixed among the cement and aggregate and heated after the curing and hardening and the molten resin is uniformly filled and solidified in voids among the respective materials such as the hardened cement to reinforce the hardened mortar product.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a mortar cured product having water repellency and having a large resistance to chemical and physical damage, weathering, friction and the like.

[0002]

2. Description of the Related Art Deterioration of a cast mortar includes internal factors of the mortar itself and external factors due to an environment to which the mortar is exposed. Are provided with various reforming means. For example, the internal factor is largely related to the water permeability of the mortar, and the movement of water causes the solute to whiten the mortar surface or cause an alkali-aggregate reaction inside. In addition, penetration of an erosive liquid (such as acid rain) may cause erosion or abnormal expansion due to a chemical reaction change, thereby causing cracking. In order to prevent these, a water repellent is applied to the surface of the cured mortar so that the liquid does not easily penetrate the mortar. In addition, in order to increase the impact resistance against compression and bending as external factors, and the durability against abrasion, chemical corrosion, etc., water-dispersed resin or reinforcing fibers are kneaded in the mortar, or polymer cement mortar is used. ing. Further, in order to improve the decorativeness as well as the durability against chemical damage and the like, after the mortar is cast, a coloring paint is applied to the mortar surface so that the mortar is colored.

[0003]

The above-mentioned reforming means is appropriately applied according to the use of the mortar, but each has the following problems. When applying a water repellent to improve the water permeability of the mortar, the water repellency of the water repellent deteriorates with time, so the water repellent must be re-applied periodically to achieve the desired water repellency. I had to. In addition, when improving the physical strength of the mortar by kneading the water-dispersed resin or the reinforcing fiber, the selectivity of the water-dispersed resin and the reinforcing fiber is used unless a limited combination of cement and aggregate is used. I couldn't do that. In addition, when using polymer mortar, selecting a polymer with excellent dispersibility and acid resistance can reduce the internal voids in the mortar, increase bending, increase compressive strength, and increase chemical resistance. Because of the plasticity, dirt, dust, dirt, and the like easily adhere to the cured mortar surface, and it is difficult to remove these contaminants. In addition, when the paint is applied to improve durability and decorativeness, the paint must be reapplied periodically as in the case of the water repellent.

[0004] That is, as for each modifying means, those which are treated after the mortar is hardened require regular repair to maintain the quality of the mortar, and those using a composite mortar kneaded with fiber, polymer, etc. are used for general purpose. It could not be used in. Accordingly, the present invention has been made in view of such a problem, in particular, by improving water permeability, which is a factor inducing deterioration, maintaining a predetermined water repellency, and eliminating the need for periodic repairs as in the conventional example. It is an object of the present invention to provide a method for producing a mortar cured product having high strength and high resistance to chemical and physical damage, weathering, friction, and the like, and a mortar used for the method.

[0005]

Means for Solving the Problems In order to solve the above problems, a method for producing a cured mortar of the present invention uses a mortar obtained by mixing a powdery thermoplastic resin with a base material mainly composed of cement. It is characterized by heating at a temperature at which the thermoplastic resin can be melted after casting and curing for a predetermined period. According to the present invention, since the powdered thermoplastic resin is used, it is uniformly diffused and mixed between cement, aggregate, and the like, and is uniformly mixed, so that the gap between each material is formed. And the surface and the interior of the mortar that has been cast are made dense. Then, by heating the mortar once cured and melting the thermoplastic resin, the molten resin uniformly fills the gaps between each material such as the hardened cement and aggregate, and deforms into a shape that closes the gaps And solidifies into these materials. Therefore, the liquid hardly permeates on the surface and inside of the mortar, the water permeability which is a main factor inducing the deterioration of the mortar is improved, and the whitening of the mortar surface and the erosion of the inside by the penetrating liquid can be suppressed. Further, by mixing an appropriate amount of the thermoplastic resin, the weight becomes lower than that of the mortar cured body having the same volume.

It is preferable to use a mortar obtained by mixing a thermoplastic resin powder in an amount of about 5 to 30% by weight with respect to cement. If the amount of the thermoplastic resin powder is less than 5% by weight of the cement, a sufficient water repellent effect cannot be obtained, and if the amount is more than 30% by weight, the water repellent effect can be obtained. The above range is appropriate because the physical strength is reduced and the material is difficult to handle, for example, it is easily broken before heating. In addition, as long as the base material is mainly composed of cement, it is possible to mix and use materials of appropriate components such as aggregates and pigments in an appropriate ratio.

As the thermoplastic resin to be blended, resins of various components such as polyethylene resin, polyamide resin and elastic polyamide resin are appropriately selected and used within a range where the cured mortar can maintain sufficient strength. it can. In addition, if a thermoplastic resin is blended in the above ratio, water repellency can be imparted to the mortar cured body, but depending on the type of the thermoplastic resin to be blended, the physical strength of the mortar against compression or bending may be increased or the mortar may be increased. The surface can be formed densely to make it less likely to be stained, or it can be improved in wetting color development by bonding with an added coloring pigment. For example, those containing a polyethylene resin are excellent in water repellency and slim color development, and those containing a polyamide resin are resistant to bending and compression. After casting the mortar containing the powdered thermoplastic resin, the temperature for heating the mortar can be 100 to 250 ° C. at which the thermoplastic resin can be melted. The above range is appropriate because heating to 250 ° C. or higher may reduce the strength of the cured mortar. The heating can be performed for an appropriate time during which the resin can be melted by an appropriate heating method depending on the melting point and the amount of the thermoplastic resin used, the shape and size of the mortar, and the like.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described based on embodiments.

[0009]

Embodiment 1 Two substrates were formed by mixing cement and aggregate (Kashima Sand No. 4), and each of the substrates was 6 to cement.
Weight% and 24 weight% of powdered polyamide resin,
After uniform mixing, 50 parts of water was charged to form a mortar. The weight ratio of cement, aggregate and resin is 1: 2
(See Table 1). After both mortars were cast and cured for 7 days and cured sufficiently, they were heated at a heating temperature of 240 ° C. for 2 hours in an electric furnace with a temperature control function, and then cooled to obtain a cured mortar.

[0010]

Example 2 Two substrates of the same material and the same composition as above
6% by weight and 24% by weight of powdered polyethylene resin were blended with the cement, respectively, mixed uniformly, and then 50 parts of water was added to obtain a mortar. The cement, the aggregate and the total amount of the resin were blended so that the weight ratio was 1: 2 (see Table 1). After both mortars were cast and cured for 7 days and cured sufficiently, they were placed in an electric furnace with a temperature control function for 2 days.
The mixture was heated at a heating temperature of 20 ° C. for 1.5 hours and then cooled to obtain a cured mortar.

[0011]

COMPARATIVE EXAMPLE 100 parts of cement and 200 parts of aggregate (Kashima Sand No. 4) were used as base materials, mixed uniformly, and then 50 parts of water was added to form a mortar. The mortar was cast and cured for 7 days, and sufficiently cured to obtain a cured mortar. The specific gravity of the mortar of each example and the comparative example is as shown in Table 1, and the mortar of each example was lighter than the mortar of the comparative example.

Test 1 Water permeability test The water permeability of the mortar cured products of both Examples and Comparative Examples was measured by JI
The test was performed in accordance with SA 6909, "Permeability test B method for architectural finish coating materials". While holding the mortar horizontally,
The funnel to which the female pipette was connected was fastened with a sealing agent, water was poured to a height of about 250 mm from the surface of the mortar, and the time required for this water to descend in the 2-ml pipette and permeate the mortar was measured. Table 2 shows the results.

Test 2 Flexural strength test The flexural strength of the mortar cured products of both Examples and Comparative Examples was measured by J
The test was performed according to IS R5201 “Physical test method for cement”. In each case, three mortar cured products serving as specimens were formed with dimensions of 40 × 40 × 160 mm, and each specimen was supported on a pair of fulcrums 100 mm apart from each other, and the middle (two equal parts) ), The maximum load was measured, and the bending strength was calculated for each. Table 2 shows the results.

Test 3 Compressive strength test The compressive strength of the mortar cured products of both Examples and Comparative Examples was
The test was performed according to IS R5201 “Physical test method for cement”. Each test piece divided into two by the bending strength test was loaded on a 40 mm square load pressing plate, and the maximum load was measured, and the compressive strength was calculated for each.
Table 2 shows the results.

As is clear from the test results, the water permeability is
The cured mortar of each of Examples 1 and 2 was lower than that of the comparative example, and had a structure in which liquid hardly penetrated. This is considered to be because the resin melted by heating filled and solidified the mortar surface and internal pores and voids so as to close them. Further, when water was dropped on the upper surface of each of the mortar hardened bodies of Examples 1 and 2 and the comparative example, the water became an elliptical sphere on the mortar surface in Examples 1 and 2, and collapsed and spread on the mortar surface in the comparative example. It was confirmed that the mortar surfaces of Examples 1 and 2 had water repellency.

The flexural strength of each of the mortar cured products of Examples 1 and 2 was higher than that of Comparative Example. It is considered that this is because the cement and the aggregate are bonded via the thermoplastic resin, and the elasticity of the resin has given elasticity to the entire mortar. On the other hand, the compressive strength of the mortar cured product containing 24% by weight of the thermoplastic resin in Example 1 is larger than that of the comparative example, and that of the mortar containing 6% by weight is almost the same.
The result of Example 2 was lower than the measurement result of Comparative Example. From these, the strength varied depending on the type and amount of the resin mixed in the mortar, and the resin and the compounding amount of Example 1 became larger than the comparative example as the physical strength including the bending and compressive strength. . In Example 1, the reason why the compressive strength of the composition of 24% by weight was higher than that of the composition of 6% by weight was that the polyamide resin had better wettability with respect to cement, and thus the resin had a higher compressive strength than the composition of 6% by weight. 24 with a large amount of mixing
This is considered to be due to the fact that the blending by weight% was more integrated.

When the chewing gum was rubbed on the upper surface of each cured mortar of Examples 1 and 2, it did not adhere to the surface of the mortar and could be easily removed. This is considered to be because the mortar surface was densely formed by re-solidification of the molten resin. On the other hand, when the chewing gum was similarly rubbed on the upper surface of the cured mortar of the comparative example, it adhered to the surface and was difficult to remove.

The mortar was kneaded at the same mixing ratio as that of the mortar containing 6% by weight of the thermoplastic resin of Example 2, and a coloring pigment was added. The body became slimy due to the action of the thermoplastic resin and had good color developability. On the other hand, a color pigment was similarly added and kneaded to the mortar of the comparative example,
The mortar cured product obtained by casting did not become wet.

[0019]

According to the production method of the present invention, a mortar cured product having excellent water repellency can be obtained, and the mortar cured product can be chemically and physically cured depending on the type and the amount of the thermoplastic resin to be mixed into the mortar. It has a large resistance to severe corrosion, weathering, friction, and the like, and can have excellent durability.

[0020]

[Table 1]

[0021]

[Table 2]

Claims (4)

[Claims] A mortar obtained by mixing a powdery thermoplastic resin into a base material mainly composed of cement, and after curing for a predetermined period, is heated at a temperature at which the thermoplastic resin can be melted. For producing a cured mortar. 2. The method for producing a cured mortar according to claim 1, wherein a mortar obtained by blending a powdered thermoplastic resin in a proportion of about 5 to 30% by weight with respect to cement is used. 3. A mortar comprising a powdered thermoplastic resin in a proportion of about 5 to 30% by weight based on cement. 4. A mortar in which a powdery thermoplastic resin is blended at a ratio of about 5 to 30% by weight with respect to cement, and the thermoplastic resin is heated and melted after casting.