CN1020890C - Silicoaluminate concrete plumping agent - Google Patents

Abstract

The present invention relates to a silicoaluminate concrete expanding agent made from silicoaluminate clinker formed by calcining silicoaluminate with specific components at the temperature of 600 DEG C to 700 DEG C as principal raw materials. The present invention has a formula which comprises the following components: 30 to 50% of silicoaluminate clinker, 10 to 40% of alunite and 30 to 50% of anhydrite. The components are mixed and milled to obtain the silicoaluminate concrete expanding agent, wherein the silicoaluminate clinker is composed of minerals of active aluminium silicate, active aluminum oxide and alphaSiO2. Silicoaluminate minerals contain very few K<+> ions and Na<+> ions, and hidden danger caused by alkali-aggregate reaction can be removed when the obtained silicoaluminate concrete expanding agent is used for hydraulic engineering. The silicoaluminate minerals have the advantages of wide distribution, low cost, low calcining temperature, greatly reduced cost of expanding agents and energy saving.

Description

Silicoaluminate concrete plumping agent

The present invention is a kind of follow-on concrete admixture.

The result who over nearly 30 years alkali-aggregate Reaction of Concrete is studied according to China shows: inside concrete is under the situation that has water and activated silica to exist, if contain K ⁺, Na ⁺The disadvantageous effect of alkali-aggregate reaction appears in the more meeting of ion, this alkali-aggregate reaction, narration in the article of nineteen ninety delivering according to the Tang Mingshu of Nanjing Chemical Engineering College professor " the prevention alkali-aggregate reaction of adopting vigorous measures ", by the adopt difference of gathering materials, alkali-aggregate reaction generally has (1) alkali-silica reaction; (2) alkali-carbonic acid reaction; (3) the alkali-silicate reaction is three types.Up to now, the alkali-aggregate reaction overwhelming majority of countries in the world generation is an alkali-silica reaction.This reaction is that the alkali in the cement produces the alkali silicate gel with active silica composition reaction in gathering materials, or title alkali silica gel, alkali silica gel has the intensive water-absorbent, the suction after causes the inside concrete expansion stress, causes concrete cracking, and the development severe patient can cause the collapse of concrete structure, therefore, the concrete that is used for important engineering, the alkali content in essential control cement, the alkali content in the also essential control admixture.

The situation of existing several cement expansive materials is listed as showing: (table is seen the literary composition back)

Comparative analysis, above-mentioned various swelling agents respectively have relative merits.No.1, No.4, No.5 swelling agent will be with preparing burden on the higher-grade alum, and the raw material reserves are few, the valency height, and the clinker burning difficulty, the production cost height, No.2, No.3 swelling agent are mainly with the preparation of lime grog, Ca(OH) ₂Be expansion sources, its gelling is poor, easily dissolved, water-repellancy are poor, and No.6, No.7 swelling agent are main raw material with the alunite, it contain potassium, sodium more, under the situation that activated silica and water are arranged, the disadvantageous effect of alkali may appear.

The objective of the invention is to select a kind of K of containing for use at above problem ⁺, Na ⁺Ion seldom, wide material sources, cheap aluminosilicate mineral (kaolin) is a main raw material, calcining is the silico-aluminate grog, add an amount of alunite and gypsum again, grind into cement expansive material, its mechanism of intumescence and effect are equivalent to excellent type swelling agent, but can be with alkali-gathering materials is reduced to bottom line.

The prescription of aluminosilicate expanding agent of the present invention is as follows:

Silico-aluminate grog 30～50%

Alunite 10～40%

Anhydrite 30～50%

Fineness control 0.08mm standard sieve tails over 5～10%

SO in the product ₃Total content is 23～28%

Silico-aluminate grog (calcined kaolin) burns till at 600～700 ℃ with special component kaolin, and its composition range is:

SiO ₂62%

Al ₂O ₃30～58%

Fe ₂O ₃1～3%

CaO????0.5～2%

MgO????0.5～2%

LOSS????1.5～3%

The mineral composition of grog is active silicic acid aluminium SiO ₂, 2Al ₂O ₃, activated alumina, α SiO ₂, active silicic acid aluminium, activated alumina can with the Ca(OH in the cement) ₂, CaSO ₄Generate ettringite (C ₃A, 3CaSO ₄, 32H ₂O), make the cement early expansion, and the solvability of alunite is relatively poor, can produces faint expansion, silico-aluminate grog and alunite with composition effect in the cement in mid-term (14～60 days) and when forming ettringite, all will absorb Ca(OH) ₂, and Ca(OH) ₂Be by C in the cement ₃S, C ₂The S aquation provides, and like this, makes the intensity foundation stone C-S-H in the cement and the formation speed of expansion sources ettringite condition each other, and promotes mutually, makes intensity and expands development coordination mutually.

Aquation in this product adding cement is graphic to be silicate cement+aluminosilicate expanding agent

The reaction formula that forms ettringite is as follows:

Below for the advantage of product of the present invention and effect:

1. this product contains potassium, the sodium amount is low, below 1%, is used for hydro project, can not produce alkali-aggregate reaction.

2. adopting kaolin, alunite, gypsum is raw material, and wide material sources are cheap, and the southwest, the Northwest that especially are fit to lack bauxitic clay and alunite produce.

3. the silico-aluminate grog can be calcined on ordinary shaft kiln, and consumption of coal is low, and production technique is simpler, and production cost is lower, is a kind of energy-saving swelling agent, and the prediction production cost is at 200 yuan/ton, and profits tax is at 150～200 yuan/ton.

4. the expansion hydrate of this product is stable, reach rational early expansion and mid-term the expansible effect, little to effect to intensity effect.

5. mix this product 10～14% in the water Buddhist nun, can mix and make expansive concrete, be used to do structure, can save outer waterproof roll from waterproof and seam repairing work, the reduction of erection time, permanent waterproof, its waterproof expense only is 1/5 of a roofing sheet comprehensive waterproof expense.

6. mix the concrete of this product 10～14% in cement, its anti-penetration grade is that 3.0Mpa improves 2 times than blank concrete.

(table is seen the literary composition back)

Embodiment is illustrated:

1. after adding 10～12% aluminosilicate expanding agents, cement setting time shortens to some extent, but in the national standard scope, can not influence the engineering time.In addition, it can not have a negative impact to strength of cement.

2. after adding 10～12% aluminosilicate expanding agents, its limited expansion rate is 5-6 a times of blank cement more than 0.04%, and contract with dry rate reduces than blank cement, has good compensate for shrinkage performance and anti-crack and anti-seepage character.

Domestic and international swelling agent situation

Numbering trade name chief component producing country

No.1 sulphoaluminate expander calcium sulphoaluminate grog Japan

No.2 lime swelling agent lime grog Japan

No.3 composite expanding agent lime grog, alunite, gypsum China

No.4 bulking agent of calcium aluminate luminite cement grog, alunite gypsum China

No.5 is excellent-I type swelling agent calcium sulphoaluminate grog, alunite, gypsum China

No.6 is excellent-II type swelling agent Tai-Ace S 150 grog, alunite, gypsum China

No.7 alumite plumping agent alunite, gypsum China

Embodiment:

Numbering alumino-silicate grog (%) alunite % gypsum % SO₂Total amount % fineness (%)

K-1    30    30    40    25.10    8.5

K-2????40????10????50????27.40????5.6

It below is the chemical ingredients of this product

Become

Compile and divide LOSS SiO ₂Al ₂O ₃Fe ₂O ₃CaO MgO SO ₃K ₂O Na ₂O

Number

K ₁8.21 22.51 16.81 2.01 18.02 1.50 26.71 0.81 0.15

K ₂9.15 26.12 14.32 1.05 16.25 0.50 24.52 0.72 0.18

This product mixes the later physical property of Portland cement No. 525

Numbering expansive agent for cement slurry initial set final set expansion rate % pressure-proof and snap-resistent

During % %: timesharing: minute water 14 the Heavenly Stems sky 28 days 7 days 28 days 7 days 28 days

K ₀100 0 2∶16 3∶52 0.008 0.031 48.5 58.5 7.4 85

K ₁90 10 1∶42 2∶12 0.042 0.09 49.5 57.5 7.3 95

K ₂88 12 1∶25 1∶58 0.046 0.012 46.3 55.4 7.1 86

National standard＞45 minute＜12 hours＞0.04＞-0.02＞30＞50＞5.0＞7.0

Claims (5)

1, a kind of aluminosilicate concrete expansion agent is characterized in that this swelling agent forms (percentage ratio meter by weight) by following material:

Silico-aluminate grog 30～50%

Alunite 10～40%

Anhydrite 30～50%

Fineness is the 0.08mm standard sieve, and tailing over is 5～10%

SO ₃Total amount 23～28%.

2, aluminosilicate concrete expansion agent according to claim 1 is characterized in that described silico-aluminate grog is formed by the aluminosilicate mineral calcining.

3, aluminosilicate concrete expansion agent according to claim 2 is characterized in that described aluminosilicate mineral is a kaolin.

4, according to claim 2 and 3 described aluminosilicate concrete expansion agents, the firing temperature that it is characterized in that described silico-aluminate grog is 600 ℃～700 ℃.

5,, it is characterized in that the chemical ingredients (percentage ratio meter by weight) of silico-aluminate grog is according to the described aluminosilicate concrete expansion agent of above arbitrary claim:

SiO ₂30～62% Al ₂O ₃30～58%

Fe ₂O ₃1～3% CaO 0.5～2%

MgO??0.5～2%??LOSS??1.5～3%