JPS6016398B2 - Method for manufacturing heat-curing cement moldings - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a heat-curable cement molded article.

In the present invention, the heat-curing cement refers to a cement that hardens slowly at room temperature even in the presence of moisture, but rapidly hardens when heated above a certain temperature.

Heat-curing cement has a slow hardening speed at room temperature and is convenient to handle, making it suitable as a material for industrially producing various cement moldings.

However, even though heat-curing cement has a slow hardening speed at room temperature, it gradually hardens in the presence of moisture, so there is a limit to its shelf life. A wet spraying method in which a mixture of aggregates such as gravel and reinforcing materials such as mineral fibers is sprayed through a pressure pipe using compressed air, heat-curing cement, water, aggregates,
A dry spraying method is used in which reinforcing materials are individually pumped and mixed at appropriate locations and sprayed, and the sprayed heat-curing cement is hardened by applying heat. However, when producing molded products using heat-curing cement using the above-mentioned molding method, even when heated, it takes time for the heat to reach the inside of the molded product, and in reality, it does not harden quickly enough. Therefore, a curing accelerator is generally used in combination.

However, if the amount of curing accelerator used is large, mechanical strength may be reduced, and there is a limit to the amount of curing accelerator that can be conveniently used. The present invention was made with the aim of eliminating the above drawbacks, and it is possible to heat-cure heat-curing cement in a short time after spraying, and there is no need to use a curing accelerator, so it is difficult to use a machine. It is an object of the present invention to provide a method for producing a heat-curable cement molded product that does not reduce its physical strength.

The gist of the present invention is to feed heat-curing cement into a pressure-feeding pipe and force it with compressed gas, supply hot water or hot steam into the pressure-feeding pipe during pressure-feeding, and supply the heat-curable cement from the entrance end of the pressure-feeding pipe to the heat-curable cement. Spraying a mixture of cement and hot water or hot steam, and curing the heat-curing cement with the hot water or hot steam,
The present invention relates to a method for producing a heat-curing cement molded article.

Next, the method for manufacturing the heat-curable cement molded article of the present invention will be explained in more detail.

In the present invention, heat-curing cement refers to cement that hardens slowly at room temperature even in the presence of moisture, but rapidly hardens when heated above a certain temperature.

Examples of heat-curing cement include Ca○・N203
There are alumina cements containing a large amount of hydraulic compounds based on the Ca○/AI203/CaX2 system, alumina halogen cements containing large amounts of hydraulic compounds based on Ca○/AI203/CaX2, etc., and these may be used in combination. Commercially available heat-curing cements include, for example, "Jet Cement" (trade name: manufactured by Onoda Cement Co., Ltd.) and "Osaka TSA" (trade name: manufactured by Osaka Cement Co., Ltd.), and both of these can be used in the present invention. In addition, other hydraulic inorganic substances such as Ca○/Si02-based hydraulic cement such as Bortland cement, gypsum, and lime may be mixed with the above-mentioned heat-curing cement, and sodium citrate, Setting rate modifiers such as gluconate may also be added. The heat-curing cement may further contain various aggregates such as sand and gravel, reinforcing materials such as natural fibers, synthetic fibers, semi-synthetic fibers, and mineral fibers, and various polymeric substances, such as rubber latex to improve waterproof performance. etc. may be mixed as necessary. An example of molding a molded article using the heat-curing cement as described above will be explained with reference to FIG. Reference numeral 1 denotes a storage tank, which contains a mixture of heat-curing cement and other hydraulic inorganic substances, reinforcing materials, and other additives as required.

Then, by opening the valve 2, the mixture in the storage tank 1 is supplied into the pressure feed pipe 3. A conduit 4 is connected to the pressure feed pipe 3 , and compressed gas in the compressor 5 , for example, compressed air, is sent from the conduit 4 into the pressure feed pipe 3 by opening a valve 6 . The mixture is forced through the pressure feeding pipe 3 using compressed gas. A spray nozzle 7 is attached to the mouth end of the pressure feed pipe 3, and the spray nozzle 7 is disposed above the mold 8. Incidentally, the spray nozzle 7 can be regarded as a component of the pressure feed pipe 3. Reference numeral 9 denotes a hot water or hot steam generator, and by opening a valve 10, a conduit 11 is inserted into the pressure feed pipe 3.
Hot water or hot steam is supplied from the pump, and the hot water or hot steam is supplied while the mixture is being pumped.

In this way, the mixture and hot water or hot steam are mixed in the pressure feed pipe 3. The amount of hot water or steam is
Although it is set depending on the amount of heat-curing cement and other aquatic inorganic substances, hot water or hot steam is supplied into the pressure feed pipe 3 during pressure feeding as described above, and it is blown from the open end of the pressure feed pipe 3. When applying water, a significantly smaller amount is required than when water is mixed with heat-curing cement and other hydraulic inorganic substances in a mixing tank, for example, without spraying.

By reducing the water content in this manner, even if the molded product is thick, cracking can be prevented from occurring after curing, and a molded product with excellent mechanical strength can be obtained. The temperature of the hot water or hot steam is preferably adjusted so that the thermosetting cement can be heated to a temperature suitable for hardening, that is, 50 to 100 CO. If the temperature rise of the heat-curable cement by hot water or hot steam is lower than 50oC, the curing speed of the heat-cure cement will be slow, and if the temperature is higher than 100oC, the mechanical strength of the cured molded product will decrease.

Although the mixture is sprayed onto the mold surface 8, it may also be sprayed to cover various objects such as plates with cement, to prevent landslides, or to cover soil with cement.
These coating layers are also included in the molded article of the present invention. According to the method of the present invention, hot water or hot steam is supplied into the pumping pipe while the heat-curing cement is being pumped with compressed gas, so that the heat-curing cement and the hot water or hot steam are uniformly mixed. The amount of hot water or hot steam required for heat-curing cement is small, and the heat-curing cement can be uniformly heated with hot water or hot steam.

In addition, since a mixture of heat-curing cement and hot water or hot steam is sprayed from the closed end of the pressure pipe, and the heat-curing cement is hardened by the heat of the hot water or steam, the sprayed heating The hardening cement can be rapidly hardened without external heating, and a desired molded product can be obtained. According to the method of the present invention, only a small amount of heat or hot steam is required for the heat-curing cement, so even if the molded product is thick, it is prevented from cracking, and the molded product is It has excellent mechanical strength such as bending strength and compressive strength. Example 1 Heat-curing cement (mineral composition: 52% ao/SiQ)
, 11Ca0・7AI203・CaF22%, 4Ca0
・Mountain 203・Fe2035%) 400 parts by weight of sand (particle size: passing the 2 h/m milestone) per 100 parts by weight were mixed in a mixer for 5 minutes, and the mixture was placed in a hopper 1 as shown in Figure 1. Compressed air was fed from the compressor 5 into the pressure feed tube 3 through the conduit 4, and the mixture was forced toward the open end of the pressure feed tube 3 at a rate of 10k9 per minute.

During the pressurizing process, hot steam was mixed into a portion near the spray nozzle 7 at a pressure of 5k9/dp, and the mixture of hot steam mixed with each other was sprayed from the spray nozzle 7 onto the mold surface 8. After spraying, a prismatic sample with dimensions of 40 x 40 x 16 plates/m and 4
Cut out a cubic sample with dimensions of 0 x 40 x 4 melon h/m,
The bending strength and compressive strength were measured one hour after spraying.

As a result, the bending strength is 42k9/block, and the compressive strength is 1 spot k9.
/ ground, and had excellent mechanical strength. Example 2 Heat-curing cement (mineral composition: Yaa○・Sj0232
%,2Ca0・Sj024%,Ca0・AI20310
%, 12Ca0・7AI2031%, 3Ca0・AI2
034%, Ca○・Tj021%, 4Ca0. AI20
3. Spraying was carried out in the same manner as in Example 1, except that a mixture of 40 parts by weight of sand (particle size: passing the 2 h/m node) per 10 parts by weight (Fe2039%, Fe01%) was used. Bending strength and compressive strength were measured in the same manner as in 1.

The bending strength was 55k9/, the compressive strength was 151 kg/, and the mechanical strength was excellent. Example 3 Heat-curing cement (mineral composition: Ca○・Sj028%
, Ca0・AI20347%, 12Ca0・7AI20
37%, Ca○・Ti024%, 4Ca0・AI203
・Fe20325%, Fe07%) 25 parts by weight, ultra-early strength boltland cement (mineral composition: Yaao・Sj026
8%, Xa○・Si025%, 3Cao・AI2039
%, 4Cao・AI203・Fe2038%) 5 parts by weight, 15 parts by weight of baked stone pipe, 9.5 parts by weight of slaked lime, 0.5 parts by weight of sodium citrate, and 80q
Spraying was carried out in the same manner as in Example 1 except that hot water marked with ○ was used.

After spraying, a prismatic sample and a cube sample having the same dimensions as in Example 1 were cut out, and the bending strength and compressive strength were measured 2 hours after spraying. As a result, the bending strength was 52k9/en,
The compressive strength was 145k9/m, and the mechanical strength was excellent. Example 4 Sand (particle size: passing the 2 h/m node) per part by weight of heat-curing cement 10 having the same composition as in Example 2
A mixture of 40 parts by weight was pumped in the same manner as in Example 1.

During the spraying process, hot steam is mixed into the area near the spray nozzle by operating at a pressure of 1.0 to 20 k9/water, and the mixture containing hot steam is passed through a spray/nozzle with an open end of 1 inch in diameter. It was sprayed onto the mold surface while changing the spraying location depending on the pressure of hot steam. Immediately after spraying, the temperature of the sprayed heat-curing cement was measured using a thermocouple. 1 hour after spraying, 40 x 40 x 4 melon h/
Cubic samples with dimensions of m were cut out from four locations and the compressive strength was measured.The location where the temperature measured by the thermocouple was 4600 was 25k9/K, and the location where the temperature was 65Ko was 1
51k9/ji, 161k9/Sakaki in the place where it was 8 degrees and 0, and 102k9/me in the place where it was 108℃.
The compressive strength was particularly excellent when heated to a temperature in the range of 5,000 to 100 degrees. Comparative example 1 Ordinary boltland cement (mineral composition: 3Cao・Si0253%, 2Ca0・Si0224%
,3Ca0・N2038%,4Ca○・N203・Fe
Spraying was carried out in the same manner as in Example 1, except that 10 parts by weight (20310%) of heat-curing cement was used, and samples were collected in the same manner as in Example 1.

However, the sample was brittle and the bending strength and compressive strength could not be measured.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an embodiment of the method of the present invention. Explanation of symbols, 1...Storage tank, 2, 6, 10...
...Valve, 3...Pressure pipe, 4,11...
... conduit, 5 ... compressor, 7 ... spray nozzle, 8 ... mold surface.

Claims (1)

[Scope of Claims] 1 Heat-curable cement is fed into a pressure-feeding pipe and pumped with compressed gas, hot water or hot steam is supplied into the pressure-feeding pipe during pressure-feeding, and the heat-curable cement is fed from the open end of the pressure-feeding pipe. A method for producing a heat-curable cement molded article, comprising spraying a mixture of cement and hot water or hot steam, and curing the heat-curable cement with the hot water or hot steam. 2. The method for producing a heat-curable cement molded article according to claim 1, wherein the heat-curable cement is mixed with Portland cement. 3. The method for producing a heat-curable cement molded article according to claim 1 or 2, wherein the heat-curable cement is heated to 50°C to 100°C with hot water or hot steam.