JPH0554549B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to an effective method for fixing gravel used as a protective holddown for a waterproof layer on a flat roof of a building. (Prior Art) Conventionally, in order to prevent the waterproofing layer of a flat roof of a building from aging due to direct sunlight and from being damaged by external forces, a so-called pressurized waterproofing method has been used in which a protective presser layer is provided on the upper surface of the waterproof layer. When a rooftop is used for walking, etc., it is necessary to pour concrete on top of the waterproof layer, but for rooftops that are not used for walking, etc., construction using gravel is used. This method involves laying gravel on top of the waterproof layer to a thickness that is at least as thick as a lid, and is quite popular in Europe and the United States.
When repairing the waterproof layer, it is easy to just move the gravel, but the natural conditions in Japan are more severe than in Europe and the United States, and the method of simply laying gravel can cause the gravel to be blown away by typhoons. As a countermeasure, the particle size of the gravel should be increased to 25 mm or more, and on large roof surfaces, the particle size should be increased to about 3 mm.
It is necessary to take measures such as installing partitions every m square to prevent gravel from gathering around the roof drain, so if you take these into account, it is not necessarily advantageous in terms of price and is not a simple construction method. hard. (Problem to be solved by the invention) Therefore, in recent years, a method of spreading asphalt emulsion or synthetic resin emulsion over gravel with a particle size of 25 mm or less has been increasingly adopted. It takes a long time for the water in the emulsion to dry and solidify due to evaporation, and if it rains during the process, the emulsion washes away, weakening the mutual adhesion of the gravel. Furthermore, since the emulsion is spread over the gravel, the amount of application tends to be inaccurate, and in some areas more emulsion than necessary is applied, which is uneconomical. Furthermore, after spreading a uniform mixture of gravel and emulsion on top of the waterproof layer,
Spray a decomposer to rapidly decompose the emulsion,
Coagulation methods have also been used, but because the decomposition starts from the upper layer of the gravel layer, the decomposer often does not reach the entire lower layer of the gravel layer, making it impossible to obtain a uniform gravel retaining protective layer. Another method is to mix a slow-acting coagulant into the emulsion in advance and spread it over the gravel, but in this case the emulsion gradually thickens and is difficult to penetrate between the gravel and the gravel. In many cases, the water hardly penetrates into the interface between the waterproof layer and the gravel. The purpose of the present invention is to eliminate all the drawbacks of the conventional gravel pressing method as described above, and to provide a stable method of fixing gravel for protecting a waterproof layer, in which the adhesion of gravel to each other is sufficiently maintained, and the gravel is not blown away by strong winds. It provides: (Means for Solving the Problems) In order to solve the above problems, the present inventors have conducted intensive research and found a method that is effective for fixing gravel used as a protective layer for waterproofing layers on flat roofs of buildings. We found a method and completed the present invention. That is, the present invention uses (A) gravel with a particle size of 5 to 25 mm, (B)
An emulsion of any one of asphalt, an acrylic copolymer resin, and an ethylene-vinyl acetate copolymer resin, (C) an epoxy resin emulsion and its curing agent, using the above (A), (B), and (C). 5 to 25 parts of (C) per 100 parts by weight of (B) in terms of solid content.
Both were mixed individually or in advance in the proportion of parts by weight, and the total amount of (B) and (C) in terms of solid content was added in the range of 0.5 to 3.5 parts by weight per 100 parts by weight of (A) and mixed uniformly. This method is characterized in that a gravel composition is prepared immediately before use, placed in a layer on the upper surface of a waterproof layer applied to the roof of a building, etc., and dried and hardened. The gravel used in the present invention is crushed stone gravel obtained by coarsely crushing raw stones such as gravel or andesite collected from rivers, and those having a particle size in the range of 5 to 25 mm are preferably used. If the particle size is 25 mm or more, there is no practical problem even if the gravel is not fixed as in the conventional method, but if the particle size is 5 mm or less, the total surface area of the entire gravel becomes large and the amount of emulsion used becomes uneconomical. It is. The emulsion used in the present invention is an emulsion of any one of asphalt, an acrylic copolymer resin, and an ethylene-vinyl acetate copolymer resin, an epoxy resin emulsion, and a curing agent for the epoxy resin. General-purpose resin emulsions can be used without any problems, but asphalt emulsions in particular have a higher penetration than straight asphalt, which is usually obtained by vacuum distillation and/or steam distillation of bitumen in crude oil. 60 to 120, emulsified using anionic emulsifiers such as fatty acid metal salts such as potassium oleate and sodium oleate, or nonionic emulsifiers such as glycerin, propylene glycol monostearate, and propylene glycol monolaurate. Emulsions made using, for example, emulsions are well known, and these are preferably used. Acrylic copolymer resin emulsions include acrylic esters, methacrylic esters,
Examples include copolymer emulsions of vinyl acetate, styrene, acrylonitrile, acrylic acid, and the like. The reason why these resin emulsions are used in the present invention is that the dry coatings of these resins have excellent weather resistance and relatively good water resistance and adhesion to gravel. Furthermore, the epoxy resin emulsion used in the present invention may be one obtained by emulsifying an epoxy resin obtained by reacting ordinary bisphenol and epichlorohydrin. As the curing agent for epoxy resins, self-emulsifying types of primary and secondary polyamines and polyamides that can be cured at room temperature can be used. The present invention decomposes and hardens the emulsion in a short time after applying a mixture of gravel and emulsion to form a uniform protective layer. By adding an epoxy resin emulsion and an epoxy resin curing agent to any one type of emulsion, the water resistance and adhesion to gravel of the dried resin film can be dramatically improved. Furthermore, since the emulsion can be cured in a short time, there is less risk of the emulsion flowing out due to rain or the like. When an emulsion such as asphalt is mixed with an epoxy resin emulsion and its curing agent for epoxy resin, it is further mixed with gravel and applied on top of the waterproof layer.
First, the epoxy curing reaction is initiated. At the same time, decomposition of the emulsion occurs, and fusion of emulsion particles and film formation proceed. Water in the emulsion also evaporates, and due to these effects, the resin coating dries and hardens within a short time after application, resulting in water resistance. The amounts of the epoxy resin emulsion and its curing agent added to the asphalt emulsion are 5 to 25 parts by weight per 100 parts by weight of the former in terms of solid content. If it is less than 5 parts by weight, curing is slow and it takes more than 24 hours for the resin to develop water resistance. On the other hand, if it exceeds 25 parts by weight, the curing will be too rapid and it will be difficult to obtain a pot life during normal work, which will cause problems in construction. Further, the amount of emulsion such as asphalt, epoxy resin emulsion, and its curing agent used for mixing with gravel is 0.5 to 3.5 parts by weight in terms of solid content per 100 parts by weight of gravel. If the amount is less than 0.5 parts by weight, the amount of resin will be insufficient and the gravel will not be completely bonded to each other. If it exceeds 3.5 parts by weight, the amount of resin becomes too large and is uneconomical. When fixing gravel using an acrylic resin emulsion or an ethylene-vinyl acetate copolymer resin emulsion, it is also possible to use a colored resin emulsion prepared by adding a coloring agent to these resin emulsions in advance. The colorant used in this case is preferably an inorganic pigment with good weather resistance, such as rutile-type titanium oxide, ferric oxide, chromium oxide, or the like. At the construction site, gravel and resin emulsion can be easily mixed using a small conveyor-type mixer used for mixing concrete mortar. First, a predetermined amount of gravel is put into a mixer, and then the required amounts of an emulsion such as asphalt, an epoxy resin emulsion, and its curing agent are added individually or as a premixed mixture, and the mixture is stirred and mixed. The mixing time may be from several minutes to about 10 minutes, and it is sufficient that the surface of the gravel is completely covered with the resin emulsion. The gravel mixture obtained in this way is spread over the waterproof layer to a certain thickness, but since there is a risk of damaging the waterproof layer with the tips of the gravel, asphalt felt is placed on top of the waterproof layer.
It is best to spread a synthetic resin stretched cloth, synthetic resin film, etc. for curing, and then spread a gravel mixture on top of it. The gravel mixture is pressed down with a trowel and finished smooth to a uniform thickness. (Examples) Hereinafter, Examples and Comparative Examples will be disclosed to further clarify the structure and effects of the present invention. In this case, the total amount of emulsion added to 100 parts by weight of gravel is 2 parts by weight in terms of solid content, and the amounts of epoxy resin emulsion and its curing agent added to each resin emulsion such as acrylic copolymer resin are varied. Examples are given and their performance evaluations are also presented. Example 1 100 kg of No. 6 crushed stone (particle size 5 to 13 mm) was placed in a small concrete mixer with a capacity of 100, and while stirring, Movinyl 709 (acrylic ester-acrylic acid copolymer resin emulsion manufactured by Hoechst Synthesis Co., Ltd., solid content 46%) was added. ) with very small amounts of antifoaming agents, preservatives, anti-foaming agents, and low-temperature coating aids, and ACR epoxy.
EM-1-60 (epoxy resin emulsion manufactured by A.C.R. Co., Ltd., solid content 60%) and ACR Hardener H-23-50W (hardening agent for epoxy resin, manufactured by A.C.R. Co., Ltd., solid content) 50%) was added, but this amount was 2 kg in terms of solid content as the total amount of resin emulsion, and ACR epoxy EM was added to 100 parts by weight in terms of solid content of Movinyl 709.
-1-60 and ACR Hardener H-23-50W were added in proportions of 2.9 parts by weight and 2.1 parts by weight, respectively, in terms of solid content. The weight of the emulsion actually added was as follows. Movinyl 709 2×100/105÷0.46=4.140Kg ACR Epoxy EM-1-60 2×2.9/105÷0.6=0.092Kg ACR Hardener H-23-50W 2×2.1/105÷0.5=0.080Kg These emulsions Stir and mix for 10 minutes after addition. As a result, the resin emulsion completely covered the surface of the gravel and a uniform gravel mixture was obtained. This mixture was taken out of the concrete mixer, spread out to a thickness of about 30 mm, and pressed down with a trowel. It had a smooth finish and was able to be cured after about 9 hours. Examples 2 to 12 Gravel was fixed in the same manner as in Example 1 using the compositions shown in Table 1. Comparative Examples 1 to 12 Gravel was fixed in the same manner as in Examples by using an epoxy resin emulsion and its curing agent for acrylic copolymer resin emulsion etc. in an amount outside the range of the present invention as shown in Table 2. Ta. Performance evaluation method: Initial water resistance is determined by determining whether or not the emulsion has flowed out due to rainfall after construction.The gravel mixture was placed in a mold and cured at 20℃, and a portion of it was cut out every hour and kept at 20℃. The sample was immersed in water and the presence or absence of elution of the emulsion was visually determined, and the time until the elution of the emulsion stopped was measured. A sample that did not elute within 6 hours was rated as very good, a sample of 6 to 12 hours was graded as good, a sample of 12 to 24 hours was graded as poor, and a sample that continued to elute even after 24 hours was graded as poor. The mutual adhesion of gravel requires about an hour of pot life to pour the gravel mixture out of the concrete mixer and spread it on the waterproof layer while troweling it to a certain thickness. If the amount of the agent is too large, curing will proceed within one hour, resulting in poor adhesion between gravels. The test method is to fill a metal mold (40 x 40 x 10 mm) with gravel mixture at a room temperature of 20°C and cure it for 7 days. After curing, the sample is removed from the mold, sandwiched between iron plates (40 x 40 x 5 mm) and subjected to a compression test to determine the compressive strength. (In this case, the compression speed is 0.5 mm/min, and the test temperature is 20℃) In this way, the adhesion of gravel to each other is judged by the magnitude of the compressive strength value according to the above test method, but the compressive strength is 5 kg/cm ² The above cases are very good, 3
A case of Kg/cm ² or more and 5 Kg/cm ² or less was considered good, and a case of 3 Kg/cm ² or less was judged as poor. Indication of the type of resin used: B1...Acrylic acid ester-acrylic acid copolymer resin emulsion (solid content 46%) B2...Acrylic acid ester-styrene copolymer resin emulsion (solid content 56%) B3...Styrene-vinyl acetate copolymerization Resin emulsion (solid content 56%) B4…Asphalt emulsion
(Solid content 50%) C1…Epoxy resin emulsion
(Solid content 60%) C2...Curing agent for epoxy resin (Solid content 50%) C1+C2...Display of epoxy resin and its curing agent evaluation: ◎...Very good 〇...Good △...Slightly poor ×...
defective

【table】

[Table] (Effects of the invention) According to the present invention, by mechanically mixing specific amounts of a specific resin emulsion with epoxy resin and its curing agent into gravel immediately before construction, the gravel surface can be completely coated with the resin emulsion. Therefore, the adhesion of the gravel to each other after construction is strong, and the adhesion to the waterproof layer is also good, providing an extremely excellent holding effect. Furthermore, curing progresses in a short time after application, there is almost no risk of the emulsion flowing out due to rain, and a presser layer with high water resistance and weather resistance can be formed.

Claims (1)

[Claims] 1 (A) Gravel with a particle size of 5 to 25 mm, (B) An emulsion of any one of asphalt, acrylic copolymer resin, and ethylene-vinyl acetate copolymer resin, (C)
Using epoxy resin emulsion and its curing agent, (A), (B), and (C), each has (B) in terms of solid content.
(C) is added individually or mixed in advance at a ratio of 5 to 25 parts by weight per 100 parts by weight, and the total amount of (B) and (C) in terms of solid content is 0.5 parts by weight per 100 parts by weight of (A). A gravel composition is prepared immediately before use by adding and uniformly mixing 3.5 parts by weight, and this is placed in a layer on the top of a waterproof layer applied to the roof of a building, etc., and allowed to dry and harden. Features: Rooftop waterproof layer protection gravel fixing method.