DE2936354A1 - Mixts. for mfg. hydrothermally hardened dense silicate concrete - such as very large sand-lime panels in which binder consists of milled sand and active lime - Google Patents

Abstract

The concrete is used for large, reinforced building elements of grade B200-B500. The mixts. consists of (a) a binder made of milled silica sand and CaO; (b) coarse silica sand used as aggregate; and (c) water. The binder consists of silica sand with Blaine fineness 3000-10,000 cm2/g forming 3-11.5wt.% of the mixt., plus 4-7.8% active CaO, which is pref. slaked by 60-90%. The aggregate has a grain size modulus of 3.1-4.2. The water contains a surfactant, esp. a water soluble carboxylic acid mixt. with chain length C4-C6. The vibration parameters expressed as frequency and acceleration are on or above the limiting curve for covering the reinforcement. The mixt. is hardened in an autoclave. Used in the mfr. of sand-lime mouldings, e.g. panels 6 x 3 x 0.2 meters in size, where the formation of cracks is eliminated, but the reinforcement is completely covered.

Description

Title of the invention

Process for the production of silicate concrete mixes for large-format reinforced silicate concrete elements Field of application of the invention The invention relates to a process for the production of silicate concrete mixes for hydrothermally hardened sift silicate concrete for large-format reinforced construction elements.

Characteristics of the known technical solutions It is known that mixtures for dense silicate concrete made of 6.0 - 12.5% fire clay with a CaO content # 80% 6.7 - 14.0% quartz sand ground with an SiO2 content # 90% 73.5 - 87.3 % Quartz sand 0 - 4 and 13.5 - 18.0% water can be produced (WP 106 621). Share of the quicklime, hydrated lime can also be used, or part of the quicklime or hydrated lime can be replaced by cement. Usually, this is ground Quartz sand in a fineness of # 2000 cm² / g according to Blaine.

It is also known according to WP 126 973 that silicate concrete mixtures especially for large-format surface-active substances, preferably water-insoluble Carboxylic acids, which, among other things, delay the burning off of the quicklime, reduce the mixing water requirement or improve the fresh concrete consistency. Additionally the use of fine quartz edge with a specific surface of 3000 suggested up to 5000 cm2 / g according to blaine and certain proportions. This statement is still unsatisfactory, as it contributes to the required grain distribution of the end of the aggregate and the f @ @@ w mm Betong @@ e required amount of lime in no case.

@ de O @@ eulegungsschrift of the FRG 1 646 966 is a rough rating with a maximum core size of 3 mm. With larger proportions of aggregates be it favorable, de @@@ mten sand-lime mixture 1 - 10%, based on the whole Mixture of montmorillonite or kaolinhal minerals, preferably bentonite, to be added. Such additives, however, are favored as mixing grants for crack-free To apply large-form-like construction elements, due to a certain concrete consistency for the vibrating pool significantly increased amounts of wastewater thereby claim to crack formation during the autoclave hardening.

@@@ imale Korngr @@@ for the aggregate of 3 mm is stated in the Offenlgschrift the FRG 2 052 262 claims.

In @@ R 90 @@@ eries also relatively fine aggregate with a Grain modulus of 1.8 and 2.1 indicated. Under @@@ em grain module, the Samme The following percentage pressure table, @ st @ ilt through 100 percent, understood: Sic @@ ruck @@@ f @ the @ range 8.0; 4.0; 2.0; 1.0; 0.5; 0.25; 0.09; at # Siebrückständein % Grain modulus = 100% Ü @@ he large-format components is, for example, a Size before 6.0 x 3.0 x 0.2 m understood. Such an element size explores @@ @@ coch comprehensive measure to prevent cracking during compaction and above all during the hydrot @@ @@ len hearing and cooling completely exclude and the Reinforcement covering to @revent over the entire element cross-section. The latter Condition is of great importance to avoid corrosion of the reinforcing steel.

It is therefore not possible to use recipes for classic sand-lime brick production to be used for the production of large-format silicate concrete construction elements of particular importance is the fineness of quartz sand in the binder, usually # 2000 cm² / g according to Blaine and that of the aggregate sand of usually 0 - 1 mm, which are not the requirements for the production of large-format, high-quality components corresponding to concrete quality B 400 and B 500, regardless of the binder stand and amount of lime.

In the @@ ie @ en @ilen a binding agent consisting of ground @and and cold, not used at all.

The difficulty of producing large-format silicate concrete elements is also expressed in the @@@ thing that compared to fresh cement concrete for the vibratory compaction of silicate fresh concrete with a comparable consistency Significantly higher compression energy is required, which is at the performance limit technical Schwi @@ tables @ i @@ t. The compression energy can be expressed by a @@@@ en To be reduced to @@ water content @. However, this @@ ß @@@ leads to a high @@@ susceptibility and to an inferior related structure of the element.

Purpose of the invention The invention aims to ensure that the production takes place in advance of silicate concrete mixes i @ @@@ etige bew @@@@ silicate concrete elements, in particular For hydrothermal dense silicate concrete at Aus @@@@ @@ @@@@ dungen as well as full reinforcement around @ l @ u @ g effective compaction behavior of the fresh Silicate concrete mixes Explain the essence of the invention The invention lies in the Task is based on a process for the production of silicate concrete mixes @@ ae an assignment of the fineness and quantity of the binder components quartz sand and Burned lime and / or hydrated lime for the fineness and quantity of the aggregate sand, preferably the concrete quality 8 200 to 500, to propose and the necessary compaction and to name hard parameters.

It has been found that the silicate concrete mixture for a certain concrete quality from their solid components binder, consisting of ground quartz sand # 3000 cm² / g specific surface according to lead and lime, preferably quicklime and / or calhydrate with a sieve residue at 0.090 mm of # 10 mass%, and Additive grain, preferably quartz sand and / or silica-rich slag, as follows described is composed in such a way that a minimal use of quartz in the binder, the amount of which is determined by the fineness of the quartz sand is and this Quartz sand quantity / quartz sand fineness relation, in turn, the lower limit of the use of lime is determined in the binding medium. In diagram 1 are the binder compositions of the silicate concrete mix for concrete quality B 200 to fl 500. Grounded Only then does quartz sand as a binder component meet the requirements described for a large-format silicate concrete element, if its specific surface area according to Blaine # 3000 cm² / g It is of vital importance that one A certain amount of quartz sand must be assigned to a certain quartz sand fineness, as can be seen from Diaglsaam 1. The corresponding lime content, shown as CaO, or from actively bound CaO, is in the given quartz sand / quartz wall fineness relationship Usually, burnt lime and / or hydrated lime is combined with a Sieve residue of # 10 mass% at 0.09 mm used, with the brandy from the Production of the fresh concrete advantageously to 60 to 90% by mass with water is partially extinguished in order, among other things, to ensure that the Ensure fresh concrete. The amount of quartz and amount of lime are only set as high as that they meet the appropriate concrete quality in the silicate concrete.

The explanations relate to a specific but usual one chemical purity of the binder raw materials for quartz sand # 70 mass% tethered SiO2 and for quicklime and / or hydrated lime # 85 mass% free or active CaO, based on lime free from hydration water.

After careful compliance with the binder composition in the The limits of the boron chemical purity are limits for the aggregate grain of the grain size range necessary to a solid mixture for the production of fresh concrete to gain the lowest mixing water requirement for a given fresh concrete consistency claimed, the compression behavior especially with regard to the reinforcement coating improved and a maximally dense concrete structure above cracks after the hydrothermal Hardening results. Sand or high-silica slag is used as aggregate Use with a maximum grain size between 4.0 and 16.0 mm, preferably 8.0 mm, and a grain size range, also as a grain size module, from 3.1 to 4.2 as shown in diagram 2 is.

The mixing water content is according to Diagram 2 over the entire range of the specified grain module Wil about 0.5 - 1.0% by mass, if with known chemical additives that act as plasticizers for silicate concrete, is being worked on.

Carboxylic acids with one chain length have proven to be particularly favorable proven by C4 - J6, which were made water-soluble by saponification using NaOH, so that faster effectiveness is achieved when mixing the fresh concrete.

The complex must @@@@@@ denoting the fineness and quantity between the binder itself as well as between the binder and aggregate and the insert certain chemical additives result in silicate concrete mixes that lead to a fresh and precast concrete for large-format concrete elements with the advantages mentioned.

Such proposed silicate concrete mixes are mixed with water mixed with a mixer to make fresh concrete, while vibrating to form large-format concrete elements processing. The targeted setting of the recipe components makes it possible to the fresh concrete according to Diagram 3 with the usual technical vibration equipment to be compacted in such a way that a maximum of dense concrete structure is achieved. In each case the vibration parameters are Uber the limit curve shown in Diagram 3 must be adhered to in order to produce error-free large-format To obtain concrete elements. Surprisingly, it has been shown that between a frequency of 35 Hz to 60 Hz with an acceleration of 4.5 g to 5.0 g a particularly economical area for vibrating silicate concrete mixes for large-format concrete elements, but with the proposed compositions the silicate concrete mixes must be adhered to.

The last step in the process is the hardening of the compacted fresh silicate concrete mixes in an autoclave at temperatures around 184 ° C 3 hours heating, 4 hours isothermal holding time and 3 hours lowering of the pressure in the autoclave and a corresponding cooling.

EXEMPLARY EMBODIMENT The invention is based on the following examples are explained: Example 1 Process for the production of a silicate concrete mix for a silicate concrete of concrete quality B 300 The binding agent, consisting of the painted Components quicklime and quartz sand, made up of 5.5% by mass according to Diagram 1 CaO active or 7.7 mass% quicklime to 80 mass% partially quenched with water a CaO content of the quicklime of 90.2% by mass and 8.0% by mass of quartz sand a specific surface area of 3500 cm² / g according to Blaine, so that an amount of binder of a total of 15.7 mass% is obtained. The difference to 100% by mass solids the silicate concrete mixture of 84.3% by mass consists of aggregate sand of a grain size module of 3.52. The A @@@@@ water is 8.4% by mass, based on 100% by mass of solids. This achieves a flowability of fresh concrete that is necessary for a reinforcement coating sufficient, but not too low, to result in cracking in the hardened concrete to have The vibration of the large-format elements according to Example 1 is carried out according to Diagram 3 at a frequency of 40 iiz and an acceleration of 4.8 g. the Reinforcement is completely encased After autoclave hardening with a hardening regime 3 h heating, 4 h isothermal holding time at 184 ° C and 3 h lowering of the pressure in the Autoclave and a corresponding cooling is a crack-free concrete with a Compressive strength of 32.5 N / mm² obtained.

In the same way, silicate concrete mixes are made according to the diagrams 1, 2 and 3 compiled for concrete quality 3 200, B 400 and B 500.

Example 2 The method of making a silicate concrete mix According to Example 1, when mixed with water in the mixer, additional additions are made a surface-active sub-Ptanz PC acid DF-water soluble, a carboxylic acid chain length C4- -C6. The amount added is 0.05% by mass based to 100% by mass solids of the silicate concrete mixture.

By adding this surfactant, the amount of water used for making up can be reduced with the same fresh concrete consistency according to Example 1 from 8.4% by mass to 7.9% by mass be reduced. With complete reinforcement coating after vibration compaction and the autoclave curing according to Example 1 becomes a crack-free concrete with a compressive strength of 34.5 N / mm² obtained.

The water-soluble PC acid Df is obtained when 400 g NaOH (solid) Carefully dissolved in 1000 ml of water and then 1200 ml of PC acid DF under constant conditions Stir into the hot caustic soda is added.

This silicate concrete mix requires a certain amount under Zug @@ surface-active substances the lowest possible mixing water requirement with a certain fresh concrete consistency and on the other hand they lead to a concrete structure densest packing of the solid components already during the compaction of the fresh concrete and too minimal open porosity with the smallest pore dimensions in the autoclave-hardened Silicate concrete.

Example 3 Two silicate concrete mixes for a concrete grade B 300 are used Compiled according to the usual recipes: Receptor component silicate concrete-silicate concrete mixture 1 mixture 2 binding agent quartz sand fineness [cm² / g] according to Blaibe 2000 2000 amount of quartz sand [% By mass] 9.7 9.7 CaOactive [% by mass] 6.3 6.3 corresponds to 80% quicklime partially quenched [% By mass] 8.9 8.9 aggregate sand Amount of aggregate sand [% by mass] 8.14 81.4 grain module 2.52 3.52 Sewage water requirement [mass%] 10.2 10.2 In compliance with a fresh concrete consistency that ensures a Bowehrungsmüllung is for the silicate concrete mixture 1, which differs from the silicate concrete mixture 2 only by one The lower grain modulus of the aggregate sand differs, a higher water requirement of 10.2 mass% is required. A higher grain module (mixture 2) ird De cleaning water requirement reduced to 9.3 hasse- ° '.

The reinforcement coating is 60 Hz under the vibration conditions and 6.4 g for the silicate concrete mix 1 and 2 reached.

After an autoclave hardening with the hardening regime 3 h, heating for 4 h Isothermal holding time at 184 ° C and 3 h cooling are the large-format elements the dimensions 6.0 x 3.0 x 0.2 m interspersed with a large number of knowledge Concrete structure is not sufficiently dense and the compressive strength of the concrete is 25.0 N / mm². It is therefore not possible to use large-format concrete elements made from silicate concrete mixes Make the usual recipe. In any case, the production of the concrete quality will not succeed B 400 and B 500, if the binder sand fineness is <3000 cm² / g according to Blaine, regardless of the amount of binding sand and lime.

The advantages are therefore that with the method described large-format reinforced concrete elements can be produced which are, on the one hand, crack-free and the reinforcement completely enveloped, on the other hand, the concrete qualities B 400 and Meet 3 500.

Claims (7)

Invention claim 1. A method for producing silicate concrete mixes for hydrothermally hardened, dense silicate concrete for large-format reinforced building elements the concrete quality 3 200 to @ 500. essentially consist of ground quartz sand and @ al @ as @indmittel, coarser quartz sand as aggregate and water in that the amount of the binder components quartz sand and quicklime, preferably 60 - 90 mass, partially quenched with water and / or potassium hydrate, for the quartz sand the fine size 3000 cm² / g to 10 000 cm² / g according to Slaine for the mentioned concrete quality B 200 to 3 500 between 3.0 and 11.5 mass% and for the CaO content between 4.0 and 7.3 active mass%; the grain size of the coarser quartz sand than Aggregate, expressed as the grain modulus, is between 3.1 and 4.2; to the Mixing water is a surface-active substance, preferably one that is soluble in water made carboxylic acid mixture of chain length C4 to C6 is added; that itself the vibration parameters, expressed in frequency and acceleration, at or above the limit curve for reinforcement coating and then these mixtures be cured in an autoclave. 2. Process for the production of sílicate concrete mixes according to point 1, characterized in that for the concrete quality 8 200 the ground amount of quartz sand between 6.0 and 7.0 mass%, preferably 6.6 mass%, up to 3.0 and 4.0 mass%, preferably 3.7 mass%, with a CaO content of 4.0 to 4.5 active mass%, preferably 4.2 mass%. 3. Process for the production of silicate concrete mixes according to point 1, characterized in that for the concrete quality 3 300 the ground quartz registration between 3.0 and 9.0% by mass, preferably 3.3% by mass, up to 4.0 and 5.0% by mass, preferably 4.5 mass%, with a CaO content of 5.3 to 5.3 active mass%, preferably 5.5 mass%. 4. Process for the production of silicate concrete mixes according to point 1, characterized in that the chosen quartz registration for the concrete quality B 400 between 9.5 and 10.5% by mass, preferably 9.9% by mass, up to 5.5 and 6.3% by mass, preferably 5.3% by mass, with an active CaO content of 6.1 to 6.6% by mass, preferably 6.3 mass%. 5. Process for the production of silicate concrete mixes according to point 1, characterized in that for the concrete quality B 500, the amount of ground quartz sand between 10.5 and 11.5% by mass, preferably 11.0% by mass, up to 6.5 and 7.5% by mass, preferably 7.0 mass%, with an active CaO content of 7.3 to 7.3 mass%, preferably 7.5 mass%. 6. Process for the production of silicate concrete mixes according to point 1, characterized in that 0.005% by mass to 0.10% by mass, preferably 0.05 % By mass, based on 100% by mass of solid, surface-active substances in the mixing water can be added. 7. Process for the production of silicate concrete mixes according to point 1, characterized in that curing in an autoclave at 174 ° C to 191 ° C, preferably 134 ° C, and 3 hours of heating, 4 hours isothermal holding time and 3 hours of lowering the pressure and a corresponding cooling takes place.