JPH04114941A - Cement quick setting agent - Google Patents

Abstract

PURPOSE:To improve quick setting performance at low temperatures in a small amount of the subject agent added by incorporating calcined alunite, lime, an alkali metallic aluminate, an alkali metallic carbonate, gypsum and a cement- based mineral therein. CONSTITUTION:A cement quick setting agent is obtained by blending 10-60wt.% calcined alunite, prepared by calcining and activating at 350-750 deg.C, then pulverizing the calcined alunite and having >=3000cm<2>/g Blaine specific surface area with 10-50wt.% lime (e.g. slaked lime having <=0.5mm grain diameter), 5-45wt.% alkali metallic aluminate (e.g. sodium aluminate) having <=1.2mm grain diameter, 5-45wt.% alkali metallic carbonate (e.g. soda ash having 99.5% purity and <=0.5mm grain diameter), 1-20wt.% gypsum (e.g. anhydrous gypsum having 98% purity and <=0.5mm grain diameter) and 5-20 wt.% cement-based mineral (e.g. fine high-early-strength cement clinker powder) having 6-90wt.% calcium.aluminate-based mineral content and >=4000cm<2>/g fineness expressed in terms of Blaine value.

Description

[Detailed Description of the Invention] <Industrial Application> The present invention relates to a cement quick setting agent that can be used in the wet method, particularly when constructing or repairing tunnels, underground cavity structures, and concrete structures. This is intended to effectively increase the initial adhesion and initial strength of shotcrete mortar or shotcrete.

<Prior Art> In general, mortar and concrete are required to exhibit early initial hardening, and in particular, when mortar and concrete are sprayed upward, high initial adhesion and initial hardening are required.

For example, when spraying mortar or concrete on the top of a tunnel, etc., the mortar or concrete itself adheres within a few seconds after spraying and has enough adhesion to prevent the aggregate from falling off, and then hardens and the spraying stops. It is necessary to exhibit sufficient strength to support the weight of the layer.

As such cement quick-setting agents, various cement quick-setting agents based on calcined alumite have been developed (
JP-A-61-26538, JP-A-63-2124
Publication No. 5).

In addition, the present inventors have discovered a new composition and blending ratio of a Shichimen 1 quick-setting agent that exhibits sufficient rapid setting hardening performance for concrete when sprayed using the wet method 1 method, and have previously filed an application (Special Patent Application). Ganhei No. 152050, filed on March 6, 1999).

<Problems to be Solved by the Invention> By the way, as a cement quick setting agent using the previously applied calcined alumite, there are 0 to 60% by weight of calcined alumite and 10 to 50% by weight of lime. %, alkali metal aluminate 5-45% by weight, alkali metal carbonate 5-45% by weight, and gypsum ~20% by weight, especially at low temperatures (10°C) and at low addition. (5% of cement)
There was a problem that the quick setting performance was not good.

In view of these circumstances, an object of the present invention is to provide a cement quick-setting agent whose quick-setting performance does not deteriorate even at low temperatures or when a low amount of additive is added.

<Means for Solving the Problems> The cement quick setting agent of the present invention for achieving the above object has the following features:
Calcined alumite 10-60% by weight, lime 10-50% by weight
, 5-45% by weight of alkali metal aluminate, 5-45% by weight of alkali metal carbonate, 1-20% by weight of gypsum, and 5-20% by weight of cement mineral.

In order to quickly set cement, it is generally necessary to have appropriate amounts of soluble alumina (sodium aluminate, etc.) 2 lime (slaked lime, etc.) and soda ash, and to these, appropriate amounts of calcined alumite and gypsum are added. This improves curing performance.

The present inventors have discovered that the rapid setting performance at low temperatures and with low addition can be ensured by the presence of soluble alumina and lime, which dissolve quickly, and have thus arrived at the present invention.

That is, the cement quick setting agent of the present invention includes calcined alumite and alkali metal aluminate as an Al2O3 source,
Cementite coexists with lime as a CaO source, calcined alumite and gypsum as 803 sources, and further contains soluble alumina and calcium in order to further improve performance at low temperatures and with low addition. , at low temperature (10℃) and at low addition (5% to cement)
) at the same time improves rapid setting performance at temperature changes (10~
30° C.) and a change in the addition rate (5 to 9%).

Here, the calcined alumite used in the present invention is activated by firing aluminum alumite or iron gate stone at 350 to 750°C, preferably 500 to 700°C. This refers to things that have been crushed. Here, those fired at 350° C. or lower have a long setting time and a low hardening strength. The particle size of the calcined alumite is preferably 3000 ci/g or more in terms of Blaine specific calculus.

As the alkali metal aluminate, sodium aluminate, potassium aluminate, etc. can be used. The particle size of the alkali metal aluminate is preferably 7.2 mrn or less, preferably 0.6 mrn or less.

Further, as the alkali metal carbonate, soda carbonate, potassium carbonate, etc. can be used. The particle size of this alkali metal carbonate is preferably 1.2 mm or less, preferably 0.6 mm or less.

Further, in the present invention, quicklime or slaked lime can be used as the lime, but when quicklime is used, the curing speed tends to be delayed by the time it takes to digest the lime (usually 1 to 3 minutes).

Further, as the gypsum, anhydrous gypsum, semi-hydrated gypsum, or both types can be used, but anhydrous gypsum is more effective than hemihydrate gypsum or engineered water gypsum.

Further, as cement minerals, powder materials such as fine powder of early strength cement clinker, early strength cement, jet cement clinker powder, and alumina cement can be used, but in particular, C3A, C1. The more calcium aluminate minerals such as A7C a F2 and CA are contained, the more preferable it is, and those containing 6 to 90% of calcium aluminate minerals are used. The fineness of this cement mineral is 4,0OOcnl in plain value.
/g or more is preferred 0 In addition, the blending ratio of these is 10 to 60% by weight of calcined alumite, preferably 20 to 50% by weight, 10 to 50% by weight of lime, preferably 15 to 40% by weight, and alkali. Metal aluminate 5-45% by weight, preferably 10-30% by weight
, alkali metal carbonate 5-45% by weight, preferably 1
Preferably, the content is 0 to 30% by weight, 1 to 20% by weight of gypsum, and 5 to 20% by weight of cement minerals.

The reason why the amount of cement mineral added is 5 to 20% by weight is that if it is less than 5% by weight, the effect of improving rapid setting is small.
On the other hand, if it exceeds 20% by weight, the absolute amount of other raw materials decreases, the overall balance of the formulation is lost, and no improvement effect is exhibited, which is both undesirable.

Hereinafter, the present invention will be explained in more detail based on Test Examples and Examples.

Test example> Test example-1 1. Test method Add 240 cc of water to 400 g of cement in a plastic container, mix for 1 minute using a hand mixer, then add an accelerating agent and mix for 6 seconds. Rapid setting performance was determined by measuring the penetration resistance using a Broctor penetration tester at 2 minutes, 4 minutes, 6 minutes, and 10 minutes, respectively, immediately after adding the binder.

2 Materials used in this test example Calcined alumite powder: Calcined at 650℃, Blaine value 4
Slaked lime: Ca(OH) 290%2 Particle size 0.5mm or less.

Sodium aluminate: Al2O, 53%, Na2038.
9%2 Particle size of 0.5 mm or less.

Carbonated Soda 2 Commercially available soda ash purity 99.5 stone %2 particle size less than 0.5m+n thing.

Gypsum: Anhydrite CaSO498%.

Particle size of 0.5m+n or less.

3゜Cement mineral ■ Fine powder of early-strength clinker (Brain 6000cWr/g
)■Jet clinker powder (Brain s 50 oc/
/g) ■Alumina cement (Denkasha No. 1 product) Cement: Ordinary Portland cement.

Mixing ratio No. 1 Table 4 Test conditions 1) Addition amount of quick setting agent: 5% of cement 2) Test temperature =
10°C 5. Test Results Table 2 shows the results of tests conducted using the above-mentioned formulations.

From Table 2 and above, calcium and cement minerals are
It was found that the higher the content of aluminate minerals, the better the strength development.

This suggests that the rapid setting reaction progresses more smoothly by adding and mixing minerals (C3A: 3CaO-Al2O3, etc.) that are originally contained in cement that contribute to rapid setting as part of the quick setting agent. It will be done.

Test Example 2 In order to examine the effects of changes in the temperature conditions and addition rate, nine combinations of temperatures of 10°C, 20°C, and 30°C and addition rates of 5%, 7%, and 9% were tested. A comparative test was conducted with the product. In this test, early-strength clinker powder was used as the cement mineral, and other materials and test methods were the same as in Test Example-].

The results are shown in Table 3.

/ / /' /- /'' / / From the above results, the rapid setting performance has been improved overall, and even at low temperatures (10℃) and with low addition (5%), the improvement in quick setting performance is significant. is clear.

Example: After mixing concrete with the composition shown in Table 4 in a badger plant, the quick-setting agent of the present invention shown in Table 1 of the test example (early strength clinker powder was used as the cement mineral) was mixed. )
7% of the cement weight was added and sprayed onto the tunnel excavation surface (wet spraying is a construction method). In addition, the concrete slump is 10.5cm, the temperature is 10℃, and the thickness is 20~20℃.
Spraying was carried out at a distance of 50 cm.

At this time, the amount of concrete splashed, the initial strength test (compressive strength converted by the pull-out method), and the adhesion state were observed. Further, as a comparative example, the conventional products shown in Table 1 were added and tested in the same manner.

These results are shown in Table 5.

Table 4 Concrete mix Table 5 Test results of sprayed concrete (Effects of the invention) As described in detail above with the test examples and examples, the cement quick setting agent of the present invention has rapid setting hardening performance in the wet spraying construction method. This will greatly improve the In particular, compared to conventional quick-setting agents, it has significantly improved quick-setting performance at low temperatures and at low addition levels. In addition, the quick-setting agent of the present invention contains cement-based minerals and has the property of hardening itself, so it is less affected by the quality of the other cement than conventional quick-setting agents, and is stable. It exhibits quick setting performance.

Claims (1)

[Claims] Calcined alumite 10-60% by weight, lime 10-50% by weight
, a cement quick-setting agent characterized by comprising 5 to 45% by weight of alkali metal aluminate, 5 to 45% by weight of alkali metal carbonate, 1 to 20% by weight of gypsum, and 5 to 20% by weight of cement mineral. .