JPS6246506B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing an inorganic cured product used for building materials and the like. Hydraulic slag is used as an inorganic binder, necessary additives such as reinforcing fibers and fillers are added to it, and the mixture is kneaded with water to form a slurry. This slurry is formed into a desired shape such as a plate using a papermaking method. The inorganic cured product obtained by shaping, curing, and drying has been conventionally used for building materials and the like. However, in the production of the above-mentioned inorganic cured body, when curing and hardening the excipient, the slag does not harden easily just by increasing the curing temperature, and the curing time takes an extremely long time. Therefore, CaO (calcium oxide) is usually used as an alkaline stimulant.
etc., but the curing time is still not shortened much. On the other hand, when dried after curing, the cured product had a relatively large dimensional shrinkage. The present invention was made in view of the above circumstances, and provides a method for producing an inorganic cured product that has quick hardening of slag during curing, small dimensional shrinkage during drying, and high bending strength. be.
This will be explained below. The method for producing an inorganic cured body according to the present invention involves shaping a slurry using hydraulic slag as an inorganic binder,
This is a method for obtaining an inorganic hardened product through accelerated curing, and is characterized by adding calcium silicate to the slurry. This will be explained in detail below. The inorganic binder used here is hydraulic slag. Therefore, the main component of the matrix is slag. Calcium silicate is added to accelerate the hydration hardening of this slag. Calcium silicate is preferably used in the form of a calcium silicate slurry so that it can be easily kneaded with other raw materials, and it may be added at any stage before shaping. The amount added is preferably 10% by weight or less (hereinafter abbreviated as "%") based on the solid content of the blended raw materials, and most preferably in the range of 0.1% or more and 8% or less. If more than 10% is added, the aqueous properties tend to deteriorate when manufactured by the papermaking method.
Furthermore, since calcium silicate is bulky, the specific gravity of the produced inorganic cured product tends to be too low, which also tends to have an adverse effect on frost damage resistance. On the other hand, if it is less than 0.1%, the effect of addition is less likely to appear. By adding calcium silicate in this way, the hydraulic reaction of the slag is promoted and the curing time is significantly shortened. Additionally, dimensional shrinkage during drying is smaller than when calcium silicate is not used. In addition to the raw materials, Portland cement, various fillers, reinforcing fibers, and the like may be added. When adding reinforcing fibers, pulp,
Glass fiber or the like is used, and it is best to defibrate it before use. Furthermore, additives other than those mentioned above may be used as necessary for manufacturing convenience or to improve the physical properties of the product. Water is added to the above raw materials and kneaded to form a slurry. Next, this slurry is shaped into a desired shape, such as a plate, by a papermaking method or the like, and the obtained shaped body is cured and hardened. The curing conditions are 40%
After leaving it in the range of ~80℃ for 8 hours or more, continue to leave it at room temperature for 2 days or more. Next, by drying this, an inorganic cured product can be obtained. The method for producing an inorganic cured product according to the present invention is constructed as described above, and since calcium silicate is added to the slurry, the curing time is significantly shortened and dimensional shrinkage during drying is reduced. .
Furthermore, the obtained inorganic cured product had increased bending strength. Next, examples will be described together with comparative examples. All examples use tobermorite as the calcium silicate. This tobermorite was made as follows. Calcium oxide (CaO) and silicon oxide (SiC ₂ ) are used as raw materials, and their blending ratio is CaO/SiO ₂ =0.8. Then, water was added to these to give a water mixing ratio of 15, and the mixture was stirred in an autoclave at 180°C for 2 hours to synthesize the mixture. The inorganic cured body was produced as follows. Water was added and kneaded to the raw materials according to the formulation shown in Table 1 below to give a slurry concentration of 8%. In this case, the bulk specific gravity of the inorganic cured body produced by this blending is adjusted to be 1.00. In addition, the bulb was made of LUKP, and the glass fiber was made of alkali-resistant glass. Next, the slurry was made into paper and pressed to obtain a shaped body.

[Table] The following Test 1 was conducted on the obtained excipients. (Test 1) After curing at 80°C for 15 hours, the bulk specific gravity of the cured product was measured after natural curing at room temperature for 3 days. The results are shown in Table 2.

[Table] In each example and comparative example,
As the hydraulic reaction of the slag progresses, the weight increases,
Eventually, the bulk specific gravity will be approximately 1.00. However, the closer the bulk specific gravity is to 1 before reaching that point, that is, after 3 days of natural curing, the faster the hydraulic reaction of the slag progresses. It can be seen that the hydraulic reaction of the slag progresses faster in all of the examples than in the comparative example. For each excipient obtained previously, the temperature was 80°C.
After curing for 15 hours in an atmosphere of 150°C, natural curing for 7 days in an atmosphere at room temperature, and drying for 40 to 50 minutes in an atmosphere of 150°C to produce a dry board. Test 2 and Test 3 below were conducted for each dry plate. (Test 2) Each dried plate was left in an atmosphere at 60°C for 24 hours, and the dimensional shrinkage due to drying was measured. The size of the drying plate was 4 cm x 16 cm, and the measurement was performed using a Tobucon measuring device. The results are shown in FIG. In this figure, dimensional shrinkage is expressed as a dimensional change rate, and dry state is expressed as a weight loss rate. The origin was reached after 24 hours. If the dimensional shrinkage is large, the dimensional change rate is also large, and the weight loss becomes smaller as drying progresses. In other words, the progress of drying can be seen by the weight loss rate. When looking at the same weight reduction rate, all of the examples have smaller dimensional change rates than the comparative examples. Therefore, it can be seen that the dimensional shrinkage due to drying is small. (Test 3) The bending strength of each dry plate was measured. The size of the drying board is 5cm x 12cm, and the span length is 10cm.
Measurement was made using an autograph at HS (head speed) of 1 m/min. The results are shown in Table 3.

[Table] From Table 3, it can be seen that all of the Examples have higher bending strength than the Comparative Examples. As described above, all of the examples exhibit faster hydraulic reaction of the slag than the comparative examples, and are superior in dimensional stability and bending strength.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the relationship between the weight reduction rate and the dimensional change rate of the cured product.

Claims (1)

[Claims] 1 A method of forming a slurry using hydraulic slag as an inorganic binder and curing it to obtain an inorganic hardened body, in which calcium silicate is added to the slurry in an amount of 0.1 to 10.0% by weight based on the solid content of the blended raw materials. 1. A method for producing an inorganic cured product, which comprises curing the product at a temperature of 40 to 80° C. for 8 hours or more, and then leaving it at room temperature for 2 days or more.