JPH02208271A - Production of light-weight high-strength cured material - Google Patents

Abstract

PURPOSE:To obtain a cured material having light weight and high strength without restricting the kind of hollow siliceous aggregate by adding a siliceous fine powder in the mixing of hollow siliceous aggregate to a hydraulic cement and curing the mixture in an autoclave. CONSTITUTION:(A) A hydraulic cement (e.g. normal Portland cement) is kneaded with (B) a hollow siliceous aggregate (e.g. silas balloon or glass balloon), (C) fine powder of siliceous material (e.g. silica fume) and (D) water. The obtained kneaded mixture is formed into a prescribed form and cured in an autoclave to obtain the objective cured material having light weight and high strength. The fine powder of siliceous material used in the above process is effective in preventing the separation of the materials in kneading and increasing the strength of the cured material. The amount of the fine powder is preferably about 5-40 pts.wt. per 100 pts.wt. of the hydraulic cement.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a method for manufacturing a lightweight, high-strength cement-based hardened body that can be used primarily as structural members for architecture and civil engineering.

(B) Prior Art] In order to reduce the weight of concrete products, various types of balloons such as Shirasu balloons and siliceous hollow materials such as perlite are mixed into cement as aggregate.

In addition, flyanche balloons and silica hume are mixed into cement, water is added and kneaded, and then molded.
It has also been proposed to cure an uncured product that has been dehydrated under pressure at a temperature of around 60°C.

(c) Problems to be solved by the invention However, although the former method can reduce the weight of concrete products obtained by using siliceous hollow aggregate,
Not strong enough.

In addition, as a solution to this problem, the latter method is limited in its use to fly ash balloons among siliceous hollow aggregates, and after rough molding, the uncured material must be dehydrated under pressure.

(=) Means for Solving the Problem The present inventors believe that the type of siliceous hollow aggregate is not limited (but if siliceous fine powder is mixed in and further odocrape treatment is applied, it will be lightweight and have high strength. The present invention was completed based on the knowledge that a cement-based hardened product of

That is, the gist of the present invention is a method for producing a lightweight, high-strength hardened body, which comprises kneading hydraulic cement, siliceous hollow aggregate, siliceous fine powder, and water, and curing the mixture in an autoclave.

The siliceous hollow aggregate used in the present invention has a shell on the surface and is hollow inside, such as various balloons such as glass balloons and shirasu balloons, fly ash sintered foam, perlite, etc. It is.

Among these siliceous hollow aggregates, those with an average particle size of 10 to 6
00μm, bulk specific gravity 1.0 or less, deformation coefficient 0.5
X 102kg・f/mm or more is desirable.

When the average particle size is smaller than 10 μm, the amount of mixed pure water required to obtain fluidity increases, which reduces the strength of the cured product. When the average particle size is larger than 600 μm, the siliceous hollow aggregate acts as defects inside the hardened body, reducing the strength of the hardened body. If the bulk specific gravity is greater than 1.0, the weight of the cured product cannot be reduced. Also, the deformation coefficient is 0.5 x 102kg-f 7
If it is smaller than mm, the strength of the aggregate itself is weak, so the hollow space is destroyed during kneading, and the hardened body becomes heavy and has low strength.

Incidentally, the bulk specific gravity and deformation coefficient were determined by the following method.

That is, using a pressurized breathing test device, first, a container (1,700 ml) was filled with siliceous hollow aggregate by the jigging method, and the bulk specific gravity was determined from its weight. Next, while placing the top lid and applying a load (kg・f), use a dial gauge to read the displacement (mm) of the top lid entering the container, draw a load-displacement curve, and calculate the slope of the straight line part by the deformation coefficient (mm). kg-f/mm). At the beginning of loading, the voids between the aggregates are filled, so the deformation coefficient is small, but then it gradually increases, and at the stage where the aggregates deform and fill the voids, the deformation coefficient remains constant (straight line section).
continues, and at the stage where the aggregate is completely destroyed by further application of load, the deformation coefficient becomes small again.

The amount of siliceous hollow aggregate mixed into the hydraulic cement is determined by the desired air-dried specific gravity of the hardened material. Hydraulic cement I~
If the siliceous hollow aggregate is 300 parts by volume relative to -00 parts by volume, the air-dried specific gravity of the cured product will be about 1.0.100 parts by volume, then about 1.5. If the amount is 400 parts by volume or more, the amount of mixed pure water required to facilitate kneading and molding increases, resulting in a decrease in the strength of the cured product.

The siliceous fine powder used in the present invention is used to prevent material separation during kneading and to increase the strength of the cured product, and silica hume is a typical example. Its average particle size is 1
The thickness is less than μm, preferably about 0.1 μm.

The amount of siliceous fine powder mixed into the hydraulic cement is preferably 5 to 40 parts by weight per 100 parts by weight of the hydraulic cement. If the amount of siliceous fine powder is less than 5 parts by weight, there is no effect of preventing separation during kneading and there is no effect of increasing strength. 40 on the contrary
When the amount is more than 1 part by weight, the viscosity of the kneaded product increases, making it necessary to increase the amount of mixed pure water, which reduces the strength of the cured product.

The autoclave curing in the present invention is carried out under saturated steam at 00°C or higher, preferably in the range of 180 to 200°C.

(E) Examples Hydraulic cement (manufactured by Nippon Cement ■, ordinary Portland cement), glass balloons with the characteristics shown in Table 1 (manufactured by Jujutsu 3M ■, Class Hublus), glass balloons (Sanki Kogyo) as siliceous hollow aggregates Zankirite, manufactured by Q'A), fly ash sintered foam (manufactured by Ube Industries H1U Lite), Barley l- (manufactured by Azatubalite ■, Azatubalite), silica hium (manufactured by Elkem Japan (manufactured by Elkem Japan 11, Microsilica) and a water reducing agent (Kao C-Kosei, Mighty 150) were kneaded in the proportions shown in Table 2 to produce a cured product with a diameter of 5 cm and a height of 10 cm.The cured product was autoclaved at 180°C. Thereafter, the weight and volume of the cured product were measured in an air-dried state to determine the air-dried specific gravity.Subsequently, a compressive strength test was conducted according to JIS A1108.The results are shown in Table 2.

(f) Effects of the invention When mixing siliceous hollow aggregate into hydraulic cement I to produce a lightweight hardened body, if siliceous fine powder is mixed and autoclaved, the type of silica hollow aggregate can be changed. Even without any limitations, a lightweight and high-strength cured product can be obtained.

Patent applicant: Nippon Cement Co., Ltd.

Claims (1)

[Claims] A method for producing a lightweight, high-strength hardened body, which comprises kneading hydraulic cement, siliceous hollow aggregate, siliceous fine powder, and water, molding, and curing in an autoclave.