DD140245A1 - GIPS CEMENT pozzolan BINDER - Google Patents

Abstract

The invention relates to a volume-stable, water storage resistant and creep resistant GZP binder, universal for manufacturing can be used for all types of dense or porous GZP-bonded shaped bodies The goal of the invention is to overcome the lack of naturalness occurring pozzolans as well as usable artificial pozzolans for the production of high-quality GZP binders, in particular those with sufficient volume stability, water storage resistance and creep resistance. The object of the invention is the development of a volume-stable, water storage resistant and creep resistant GZP binder under use a chemically highly active, siliceous secondary raw material as a pozzolan component. The GZP binder according to the invention contains as sulphatic component 50.0 to 80.0% by mass of a calcined gypsum, 7.0 to 40.0 Ma, -% of a lime-releasing component and 4.0 to 33.0 Ma · a victorious residue from the mineral acid, aqueous extract » treatment of thermally and / or mechanically activated Sill rates, preferably of e-extraction-layered phyllosilicates, as a pozzolan component and the lime-releasing and pozzolan components having a mass ratio of between 4 ··· 1 0.5: 1.

Description

Field of application of the Erjfjjidunq

The invention relates to a volume-stable, water storage resistant and creep-resistant gypsum cement-pozzolan binder (gypsum cement-> Puzzolan hereinafter abbreviated as GZP), the universal for the production of all kinds of dense or porous GZP-bonded shaped body «, for example, denser or more porous GZP-Plaster, GZP lightweight aggregate concrete «dense. GZP ~ concretes _for GZP hollow concrete, GZP »gas concrete, GZP foam» concrete and «8n.

Char akter is tL4ii.JJil ^

There are already several GZP binders and processes for their preparation known in which the undesired expansion of the system calcium sulfate "Portland cement and / or slag cements and / or lime" water due to the formation of the complex Calciumalurninattrisulfathydrates ettringite by the addition of pozzolans more or less successful is influenced · In these binders have been or · method as hydraulically-active additives, for example, vermiculite (GB-Pstentschrift -No * 895393) or naturally occurring © silicas ,, for example Diatome © n _e triples and Opoka (GB Patent No. ^ 874 230 * SU ^ author's certificate No. _{6147510 e} US patent Mr * 3411924} or artificially occurring silica "* · 'unu high-alumina materials such as power plant filter ash" brick flour ₉ Qlschie-

Fer- and Torfaschen (raw, Η · -0 ·; gypsum cement-pozzolan-Baustoffe; series building materials of the construction information of the GDR, November 1973) Allen all these binders or © method is common that primarily the chemical activity of the pozzolan component both the process

, Technique for the production of GZP binders and the resulting properties of the finished binder, preferably the volume stability, but also the compressive strength, the softening coefficient, the creep u u «determined *«.

The chemical activity of a pozzolan component can be judged on the basis of its absorption capacity of calcium hydroxide. The more hydrated lime absorbed by 1 g of pozzolan in a given experimental setup, the higher the activity. "In addition to the total activity of a pozzolan component, its content of active alumina is of interest." High levels of reactive alumina and / or aluminates are undesirable in the pozzolan component of GZP binders since they inhibit ettringite formation. förderna

Now it has been tried the process steps for the preparation "Λ dor Puzzolankomponente, such as drying, grinding and sifting, s'owie the process steps for the preparation (completion) of the GZP ~ binders, such as dosage and homogenization, to be construed as a rule such that highest possible chemical Activity of the pozzolan component is achieved * _t Thus, for example, according to the ÜS ~ Patent Specification Nr _e 3 411 924 by a hot mixing process for gypsum and diatomaceous earth, the chemical activity of the finished GZP binder to be increased «

However, the main drawback of the known methods is that despite many attempts to activate the pozzolan component by high-precision milling, thermal activation, hot homogenization, the chemical activity of the

«> 3 *

137

Pozzolan component remains too low to suppress the formation of the swellable, complex hydration product ettringite in such a way that the volume stability of the GZP binders is ensured.

Starting from the demand for a high silicate lime binding of the pozzolan component, an attempt was made to develop GZP binders on the basis of natural silicas, such as diatoms, triples, and opaques. "In the literature (Volzenskiy, A _e V," Starobulko, I "V _e : Gypsum Cement »Puzzolane Binders and Concretes Based on Concrete i Zelezobeton, Moscow 4 (1358) 10 _f 363-367 and Volzenskij _f A _e V *: The character and role of change in the volumes The solid phases in the hardening of binders and concretes: Beton i Zelezobeton, Moscow 15 (1969) 3,16-20) are called for diatoms, TripeX and Opoka lime absorption values between 180 and 320 mg CaO per 1 g of silica. Natural silicas are therefore depending on their levels of active silica, alumina and iron oxide, more or less for the production of GZP binders suitable GZP- "Bindeinittel _e made using natural silicas with Al ₂ O ₃ - and Fe ₂ 0_" Ge ~ When hydration was maintained at levels of 4 to 10% by mass, there were positive, linear changes in length between O _f 8 and 2 _p 0 mm / m GZP binder, using natural silica with AX ₂ O - and Fe ₂ O ₃ "content of about 10 to 20% by mass were prepared showed _f r d & hydration positive, linear changes in length between 2 and ₈ 0 4 _e 0 mm / m _e

In addition to the conditional volumetric stability, however, the silica of sedimentary origin is strictly limited in territorial terms and often precludes only in minor proportions, so that the production and use of GZPs, especially in buildings, is measured by the ratio of mangsl-a to active silica _# only to a very limited extent «

An often equally good lime absorption capacity as the natural silicas If artificial pozzolans, for example power plant filter ash on oil boats, promote their generally high aluminate contents the undesired ettringite formation, so that with these pozzolanic ashes a production of GZP binders is not possible or in the production of inferior, GZP binders not stable to volume (Wegner, WD, and Roher, He-CJ .: Gypsum Cement Puzzolan Building Materials; Building Material Industry, Edition B 18 (1975) 2, 25-29), which can not be used in the construction industry «

Object of the invention

The aim of the invention is the overcoming of the lack of naturally occurring pozzolans and of usable artificial pozzolans for the production of high-quality GZP binders, in particular those having sufficient volume stability, water storage resistance and creep resistance.

ΡΑ§ ^^ Ρ!?,. H ^ Hf, you, the invention is solved

The invention has for its object to develop a volume-stable, water storage resistant and creep resistant GZP binder using a chemically highly active, silica-rich secondary raw material as a pozzolan component.

Merk ma Ie ₁ de r He, find £

A volume-stable, water storage-resistant and creep-resistant GZP binder was found. The GZP binder is characterized in that the binder

as sulfatic component between 50.0 and SO, O

Mass «=% of a calcined gypsum, preferably β- gypsum, <* - gypsum, anhydrite or screed gypsum or a mixture

from these,

between 7.0 and 40.0% by mass of a lime-releasing component, preferably Portland cement, slag cement, hydraulic lime or nonhydraulic lime or a mixture of these and

Between 4.0 and 33.0% by weight of a SiO 2 -rich residue from the mineral acid, aqueous extraction preparation of thermally and / or mechanically activated silicates, preferably of extraction-processed sheet silicates, of a chemical composition (in% by mass)

SiO ₂ between 50.0 and 98.0 Al ₂ O ₃ 0.1 and 20.0 ^Fe 2 ° 3 0.1 and 3.0 CaO 0.01 and 3.0 MgO 0.01 and 10.0 TiO ₂ 0.2 and 4.0 κ ₂ ο 0.1 and 3.0 Na ₂ O 0.01 and 1.0 ^S0 4 ² ~ 0.00 and 12.0

Cl "0.00 and 0.5

NO ₃ "" 0.00 and 0.5

Glühverlus.t

1OSO ⁰ C, 1 h 2.0 and 20.0

as a pozzolan component

and

«The kaikspendendo and the pozzolan component with a mass ratio between 4 t 1 and 0.5: 1, preferably between 3: 1 and lsi

contains «".

As a particularly advantageous pozzolan component, the GZP binder according to the invention, the SiO ₂ -rich residue from the mineral acid, aqueous extraction preparation of thermally and / or mechanically activated aluminum-containing phyllosilicates, preferably extraction-prepared Pyrophyllite, Glimmers, hydrogels, montmorillonite, vermiculite, chlorite , Kaolinite, dickite or nackrit or their naturally occurring mixture, such as clays or kaolins, contain «

As another, particularly advantageous pozzolan component, the GZP binder may contain the SiO.sub.p-rich residue from the mineral acid, aqueous extraction preparation of thermally and / or mechanically activated magnesium phyllosilicates, preferably extraction-processed talc, antigorite (serpentine) or chrysotile (fibroserpentin) *.

These mentioned, usable in the production of GZP binders as particularly advantageous pozzolanic, SiQp-rich residues fall among other things in the chemical engineering process of aluminum extraction from thermally and / or mechanically activated aluminum-containing phyllosilicates and in the chemical-chemical processes of Mag · »Nesium extraction from thermally and / or mechanically activated magnesium phyllosilicates with the help of mineral acids *

As a pozzolanic component, the GZP binder should contain the StO * rich extraction treatment residue in the dried state and with a degree of dryness guaranteeing that no capillary adsorptively bound "physically free water remains in the treatment residues. * Water, on the other hand, in the form of functional hydroxyl groups is chemically bound, does not interfere with the use of the extraction treatment residues according to the invention * The GZP binder should continue as a pozzolan component the SiO ₂ -rich extraction treatment residue with a particle size distribution

Grain fraction greater than 90 - less than 10 mass%,

Grain fraction between 63 and 90 μm between 5 and 20% by weight,

Grain fraction between 40 and 63, by between 10 and 25 mass%,

Grain fraction less than 40 μm between 50 and 80% by weight

contain·

For the inventive GZP binder as a pozzolan component, SiO _2- rich extraction residues according to the invention have, in addition to the extraordinarily favorable chemical composition, a favorable mineral constituent, a highly porous microstructure with a high specific surface area and internal, functional hydroxyl groups The usable residues, according to their mineralogical composition, to 60 to 80 mass / 6 of substances that are very reactive towards alkaline solutions, primarily from X-ray amorphous silica, but also from reactive metakaolinite, reactive alumina and magnesium oxide. The fine capillary pore structure has a specific pore volume between 0.20 to 0.50 cm / g. The inner surface, likes to eat

according to BET, lies in the value range between 50 and 300 m / g «. The particular size of the specific pore volume and the specific surface area depends on the degree of application of the value components aluminum or magnesium oxide from the thermally and / or mechanically activated silicates; but they have no significant influence on the applicability of these extraction processing "residues" according to the invention.

Due to the favorable chemical and mineralogical constitution _{t of} the large and easily accessible inner surface of the extraction treatment residues and the occupancy of the inner surface with functional hydroxyl groups, they have an above-average chemical reactivity to calcium hydroxide solutions (Kalkahsorptionsvermögen) "Thus, the lime binding per 1 g extract ionic treatment residue at a reaction

1! 37

I % 3> β

temperature of 20 ⁰ C, determined in shaking experiments with initially saturated Calciumhydroxxdlösung

after 1 day between 160 to 190 mg CaO / 1 g residue after 3 days between 340 to 390 mg CaO / 1 g residue after 28 days between 500 to 600 mg CaO / 1 g residue

Furthermore, according to the Soviet standard MRTU 21-8-65, the lime concentrations in suspensions of 1 g gypsum, 2.5 g Portland cement and η · 2.5 g extraction treatment residue in 100 ml distilled water for various freely chosen "η" after 5 days Reaction time measured at 20 C:

η mg CaO / 100 ml

0 124

0.3 between 79 and 83

0.5 between 27.5 and 38.9

0.6 between 17.9 and 23.6

1.0 between 8.1 and 10.5

The requirement of the Soviet standard MRTU 21-8-65, which for properly chosen ^M η "after 5 days of reaction time at 20 C, the lime concentration in the suspension should be equal to or less than 110 mg CaO / 100 ml solution is of all tested here GZP mixtures which contain the extraction treatment residue to be used according to the invention,

Due to this high lime binding ratio, the formation of the swellable complex hydrate ettringite is very rapid in optimally assembled GZP binders and the hardened GZP moldings undergo extremely low elongation after solidification.

The expansion process of the GZP binder according to the invention is clearly of their. Al η content dependent ", For a binder low in AlgOg, the expansion process is essentially completed by the 3" hardening day, at a

". 9 =

A1 _? The higher the binder, the elongation will reach between 80 and 90 % of the final value by the hardening day. After that, the source process sounds asymptotic.

A GZP binder with a total Al ₂ O ₃ content of about 3% by mass undergoes positive, linear changes in length of 0.10 to 0.20 % in the case of water storage up to the 90th day of hydrotation, while the test specimens harden the air. with a relative humidity of 60%, the degree of elongation is lower; In addition, expansion and shrinkage processes are compensated in a compensatory manner, so that the linear strain is +0.03 to a maximum of + 0.05 % . The expansion dimensions are based on the length of a newly solidified, demouldable GZP plaster test specimen »

A GZP binder with a lower Al _? 0 ~ ₃ ~ Gesamtge content of about 1.8% by mass undergoes during storage in water until the 90. Hydratationstag positive linear change in length of * 0.09 to + 0.12% "during storage in air with a relative humidity of 60% is the elongation degree up to the 90th day of hydration + 0.01 to maximum * 0 ₄ 03 % t based on the dimension of a GZP plaster test specimen just solidified »

By contrast, known GZP binders, for example those based on the lignite filter bag Hagenwerder (DDR), show positive, linear changes in length of between 1.0 and 1.4 % by the day of hydration (Wegner, W _e D _e and Roher, H # -3 _e : gypsum cement-pozzolan building materials, building materials industry, edition B, 18 (1975) 2, pages 25 to 29).

The GZP binder according to the invention combines the advantages of typical early curing and hydraulic posthardening. Thus, the mechanical strength (wet compressive strength) of pure GZP gypsum of about 4 MPa increases after 2 hours of hardening. to 15 to 16 MPa after 28 days of hardening and to 17 to 18 MPa after 3 ° C hardening.

- 10 -

The stiffening of mixed with mixing water GZP binder is comparatively accelerated to stiffen the corresponding pure sulfate component. As setting agents for the regulation of the stiffening times, it is possible to use conventional gypsum setting retardants, which act both on the basis of protective colloid formation on the gypsum and on the basis of the reduction in the solubility of the gypsum. The type and concentration of the retarding agent is to be optimized depending on the technologically required flow behavior, the desired casting and brushing times as well as the required early and final strength. By adding, for example 0.20% by volume of a protein hydrolyzate, based on the amount of mixing water at a water-GZP ratio of 0.55, the solidification start (end of the casting time) of the GZP binder is from 1 to 3 minutes to 6 to 9 delayed and the solidification end (end of the brushing time) from 10 to 14 min to 14 to 18 min postponed.

In addition to good mechanical properties, the GZP binder according to the invention is characterized by moisture resistance and a finite creep.

The moisture resistance of the GZP binder according to the invention comparatively to the pure calcium sulfate component is characterized by the increase in the ratio between the wet and dry strength. While in Purgipspiastern the ratio between the wet and the dry strength, the so-called softening factor, between the values 0.30 and 0.45 varies, increases in the present, optimally assembled GZP plaster, the softening coefficient to values between 0.81 and 0.84 on*

Pure gypsum binders break suddenly under static load after a creep process that proceeds largely linearly over the loading period. The GZP binder according to the invention, with which this serious. Disadvantage of pure gypsum binders is overcome, is characterized

- II -

1 3-7

1 «SI #

also by a change in the character of the creep process (creeping process) and a significant

d3 edge reduction of Kriechformation from · the absolute creep index £ _K of GZP-binder of the invention was determined using a GZP fine sand mortar · In a mortar mixing ratio GZP: sand: water of 1: 2: 0.65 of creep process is at 20 ⁰ C and a relative humidity of 60 % between the 120 and 180 test days, and thereby approaches a final value of the creep deformation C _K of 0.8 per cent.

The preparation of the GZP compound according to the invention can be carried out as follows:

The use of the extraction treatment residues as pozzolanic component should be carried out in a visually dry, free-flowing state. For this purpose, the aqueous-wet residues obtained during the extraction treatment must first be mechanically and / or thermally dehydrated in any drying or grinding drying unit until the water content related loss on ignition of the dried extraction residues at 1050 ⁰ C and 1 hour of annealing a value between 2.0 and 20.0% by mass, preferably between 4.0 and 8.0 mass%, achieved. The grinding process of the dried extraction tailings _(t grain diameter between 0 l and 3 mm) in pellet form (particle diameter of between 3 and 15 mm) or semolina-like form may be present, should be performed so that the residues after completion of milling or mill-drying process in the previously given grain size distribution *

Mixing of the individual components using already finely divided sulphate and lime-releasing components can be carried out by any process which ensures good homogenization. In the presence of lumpy sulphate and lime-releasing components and pellet-shaped extraction treatment residues, it is due to the different Mahlvyider levels of the components advantageous _s the components in

- 12 -

, '. , ü

a multi-chamber cement mill and to homogenize, the soft components, the sulfatic component and the extraction processing residue (the pozzolan component), only in the last chamber to be added-

Explanatory Note

The invention will be explained in more detail by the following embodiment, but the invention is not limited to this example *

From calcium sulfate hemihydrate (stucco SG 9, grade II to GDR standard TGL 21843), portland cement of grade PZ 1/425, rich in aluminate with 10.6 % tricalcium aluminate (to GDR standard TGL 28101) and from 2 extraction treatment residues (from the HCl acid Leaching of calcined phyllosilicates) of the chemical composition (in% by mass)

SiO ₂

Fe ₂ O ₃ CaO MgO TiO ₂ K ₂ O

Residue A Residue B 72.94 83.51 14.46 4.33 1.64 1.09 0.056 0,017 0,065 0.028 2.96 .3,18 0.93 0.45 0,038 0.031 0.00 0.00 0.21 0.07

Cl ""

loss on ignition

1050 ⁰ G, 1 h 6.61 - 7 _S 22

and a particle size distribution (in% by mass)

- 13 -

Residue A residue B

Grain fraction greater than 90 to grain fraction between 63 and

90 .um grain fraction between 40 and

63, to grain fraction less than 40, um

2,3 11,6

23.1 62.0

1.7 8.1

24.4 65.8

2 GZP binders were produced * The GZP binder (A) has a total Al.Og content of about 3 % and the GZP binder (B) has a total Al ₂ O ₃ content of about 1.8 % on *

Both GZP binders were tested for their volume stability, their strength development, their softening behavior, their stiffening behavior and other characteristics. The GZP binder (A) was examined for its creep behavior. "

The length changes and strength development of the GZP binders were tested on prism-shaped test specimens of dimensions 4 χ 4 χ 16 cm. "The changes in length were measured with the aid of a dial gauge comparator." The length measurements were based on the dimensions of a newly solidified, demountable GZP -Plaster test body based. The creep test was performed on a dense GZP (A) fine sand mortar. For creep testing, prism-shaped test specimens of dimensions 10 × 10 × 40 cm were used «

Measurements table indices

Mixing ratio * G: PZ: E (M-%) ^:

^A1 2 ° 3 ge

, a W

GZP (A)

3.04

GZP (B)

67: 20: 13 57 ϊ 22: 11

1.82

- 14 -

- - 14 Continuation Measured values table

Water ~ ~ GZP ratio

C-]

0.65

Setting without retarder start min end min

Setting with retarder start min end min

Raw density plaster, damp J g / cm ^ J

Raw density plaster, dry | g / cm J

2) D β ο β / eee 16

1.67

1.18

0.65

empty 2 2 β ο β _βββ 12 12 _eee

16

19

Naßdruckfes at the age of 3.9 4.9 2 h 4.6 5 * 4 1 d 9.9 10.2 [MPa] 3 d 15.6 17.6 28 d 17.3 18.2 90 d

'Eo means G ~ gypsum hemihydrate? PZ = Portland cement;

E - extraction residue

'Retarder protein hydrolyzate

Wet bending tensile strength at the age of

[MPa]

2 h

id

3 d 28 d 90 d 5U97 2.01

2,93 5,32

5, SO

2.04 2.11

5.10 5.71

~ 15

- 15 Continuation Measured value table

Free stretching under water in%

after 2h + 0.010 + 0.012

Id + 0.019 + 0.025

3d + 0.08 "5 + 0.060

7d + 0.135 + 0.091

28d + 0.160 + 0.108

9Od + 0.191 + 0.120

Free expansion in air with RH 95 %

after 2h + 0.010 + 0.010

Id + 0.015 + 0.010

3d + 0.060 + 0.018

7d + 0.082 + 0.029

28d + 0.090 + 0.030

SO d * 0 _t 095 * 0.032

Free expansion in air with r _e F «60 %

after 2h * 0.010 + 0.010

Id + 0.013 * 0.010

3d + 0.050 + 0.016

7d * 0.054 * 0.026

28d + 0.040 + 0.017

.9Od + 0.029 + 0.011

Adjustment coefficient

^R pressure 23 d wet _n ^

0.84 0.81

pressure 28 d. dry

Kriechniaß Zv

for G2P (A) fine sand mortar in [ / ooj

after ISO days at 20 ^° C. and 60 % RH ·

Claims (4)

I * Volume-stable _β water-storage-resistant and creep-resistant gypsum-cement-pozzolan binder characterized in that the binder «As a sulfatic component between 50 ^ 0 and 80 _e 0% by mass of a calcined gypsum, preferably β- gypsum, ^ »GipSi anhydrite or screed plaster or a mixture of these _e ~ 7.0 to 40 _s 0 mass% of a kalkspendenden "component _e is preferably Portland _cement? Slag cement, hydraulic lime or hydraulic lime, or a mixture of these,
and - _f 0 and 33% mineral acid _t Ö Hasse a siop-rich supernatant from the rear * 'between 4 aqueous extraction processing of thermally and / or mechanically activated silicates, preferably von.extraktionsaufbereiteten phyllosilicates _β of a chemical composition "reduction (in mass ~%) between 50.0 ₃ between 0 _s l ^ ⁸ 2 ^ 3 between 0 _f . i CaO between 0 _e 01 MgO between O ^ Qi TiO ₂ between 0 ^ 2 KpO between 0 _p i '/ »4? - i ₂ O between 0.01 and 1.0 SO ₄ ² ~ between 0.00 and 12.0 Cl "between 0 _f 00 and 0.5 NO ₃ * "between 0.00 and 0.5 loss on ignition 1050 ⁰ C, 1 h between 2 _e 0 and 20.0 as a pozzolan component
and the lime-releasing and pozzolanic components having a mass ratio between 4: 1 and 0.5 s 1, preferably between 3: 1 and 1: 1, contains " 2 «gypsum cement pozzolan binder according to item 1, characterized in that the binder as a pozzolan component of the SiO ₂ « rich residue from the mineral »- acid, aqueous extraction preparation of thermally and / or mechanically activated aluminum-containing phyllosilicates, preferably extraction-processed pyrophyllite , Mica, hydrogels, montmorillonite, vermiculite, chlorite, kaolinite, dickite or nackrit or their naturally occurring mixtures such as clays or kaolins, 3. plaster-cement-pozzolan binder according to item 1, characterized in that the binder as Puzzolankosnponente the SiO ₂ ~ rich residue from the minarslsauren, aqueous Extroktionsoufbereitung of thermally and / or mechanically activated magnesium phyllosilicates, preferably extraction-processed talc, Antigorit ( Serpentine) or chrysotile (fiber serpentine), contains « 4 'gypsum cement-pozzolan binder according to item i to 3, characterized in that the binder as Puzzo lankkomponente the SiO "rich extraction treatment residue with a particle size distribution Grain fraction greater than 90, to less than 10 mass-5o, grain fraction between 63 and 90, to /. _ Grain fraction between 40 and 63, grain fraction less than 40, um contains between 5 and 20 mass%, 3, um between 10 and 25 mass%, between 50 and 80% by mass »