DE3248571A1 - Reactive resin mortar or concrete - Google Patents

Abstract

A reactive resin mortar or concrete consists of a reactive resin as a binder in which additives of different particle sizes are embedded as fillers. The amounts by volume of the individual particle size ranges of the additives essentially correspond to a filler line or a sieve line according to DIN 1045. In order to avoid undesired thermal stresses at the boundary layer with steel or mineral concrete even in the case of a relatively high modulus of elasticity, at least in the upper range of the sieve line the additives are chosen so that the coefficient of thermal expansion of the additives is greater in a particular particle range than in the adjacent particle range with a smaller particle diameter. Overall, the amounts and the coefficients of expansion of the additives are such that the coefficient of linear expansion of the cured material is between 9.10<-6> and 15.10<-6> m/mK.

Description

Reaction resin mortar or concrete

The invention is based on a reaction resin mortar or concrete from a reaction resin as a binder, in the aggregates of different Grain size are embedded as fillers, with the volume fractions of each Grain size ranges of the aggregates essentially correspond to a Fuller's line or a grading curve according to DIN 1045.

In concrete technology, it is known to use such reaction resin mortars and concretes or -screeds to use instead of mineral concretes, mortars or screeds, -da them in some respects, such as water absorption capacity and durability against aggressive substances, have advantages. Also for repair and renovation Such reaction resin mortars are removed from damaged mineral concrete parts or -concrete used.

However, the previously known reaction resin mortars or concretes have on average has a coefficient of linear thermal expansion that is by a factor of 1.5 up to 3 is greater than the linear thermal expansion coefficient of mineral concrete or cement, which is about 12.10-6 m / mK. Because of this different expansion coefficient arise with changing Temperatures significant tensions at the boundary layer between synthetic resin concrete and mineral concrete, the occurring Stresses essentially the product of the modulus of elasticity of the synthetic resin concrete and the difference in the thermal expansion coefficient are proportional.

So far, attempts have been made to reduce the modulus of elasticity of the synthetic resin concrete to keep the tension as small as possible in the sense of a reduction of the tension, which however on the one hand to a high proportion of binder and on the other hand to ultimately one relatively soft hardened synthetic resin concrete leads.

No usable composite structures can be used here either Manufacture of steel reinforcement as it is used in concrete technology mineral concrete are known and widespread.

The object of the invention is therefore to provide a reaction resin mortar or concrete to create, in which, even with a relatively high modulus of elasticity, no undesirable, thermal caused stresses occur at the boundary layer with steel or mineral concrete.

The reaction resin mortar according to the invention is used to solve this problem or concrete characterized by the features of the main claim.

By choosing the additives in such a way that with each Grain size range the coefficient of thermal expansion is greater than in the neighboring Grain size range with a smaller gor diameter results practically as a function the grain size increasing coefficient of thermal expansion, the the The advantage is that with the necessary large grain diameters of the aggregates the shear stresses between binder and aggregate throughout the cured Mass can be kept so low that no detachment of the binder from the aggregates occurs due to thermal effects.

The fact that the volume fraction of a respective grain size range continues on the expansion coefficient of the aggregate used in the area adapted or vice versa for a given coefficient of expansion of the aggregate used the volume fraction of which is measured in the manner according to the invention results in a cured mass, the linear expansion coefficient of which is related to the linear expansion coefficient of steel or mineral concrete is adapted.

Because possibly fine grain fractions with low thermal expansion coefficients are relatively expensive, can also for the grading curve range below about 0.5 mm additives with a coefficient of expansion that are greater is than in the grain range above 0.5 mm.

Deviating from the grading curves for the mineral aggregates In the case of reaction resin mortar or concrete, it is advisable if the fine grain content the grading curve has additives with a diameter of less than 0.05 mm. The largest grain fraction of the grading curve is expediently at most 32 mm.

To prevent the binder from occurring under certain circumstances flows away from curing due to insufficient inherent viscosity, the Finest grain content increases the viscosity of the binder characteristic have, for example by having a leaf-shaped, elongated or spiral-shaped Has shape.

The coefficient of thermal expansion is further reduced when In the finest grain area, aggregates are used that sorptive the binding agent tie. In addition, this also increases the viscosity in a favorable manner the shrinkage behavior is reduced.

If the aggregates for the reaction resin mortar or concrete are aerophile wine additives are mixed in, the result is an improved hardening Shrinkage behavior of the mass and thus lower internal stresses.

Dangerous shear stresses are avoided when the aggregates of the largest grain area is close to the expansion coefficient of the binder have lying thermal expansion coefficients. An advantageous value the expansion coefficient of the additives in the largest grain area about 10 10 6 6 to 14,106 m / mK.

If there are no aggregates for a given grain size range with suitable thermal expansion coefficients can be obtained, this grain size range also from different aggregates with different expansion coefficients exist, so that the desired expansion coefficient results in cooperation.

In the drawing, an exemplary embodiment is shown in a diagram Invention shown.

In the case of the reaction resin mortar or concrete according to the invention, the resulting coefficient of thermal expansion «tot for the cured mass results in a first approximation according to the formula where: = = volume fraction of the binder, based on the cured mass, o (= linear thermal expansion coefficient of the binder taking into account the sorbtively bound fraction of the binder, Yn = volume fraction of the grain size range n in the total volume of the cured mass and tn = linear thermal expansion coefficient des n of the aggregate used in the grain range n If 1 is assumed for the total volume, then applies to y Because of technically unavoidable air inclusions, which make up a relatively small volume fraction, equation (2) does not apply exactly.

About the shear stresses of the hardened mass at the boundary layer Keeping the aggregates small between the binder and the aggregates is what chosen for the individual grain size ranges n so that the grain size range with the largest grain size also the largest thermal expansion coefficient R and the coefficient of thermal expansion d then of the grain size range to grain size range n drops to a minimum value which it in the grain size range of the fine grain used in each case. It thus results in a with the Grain size increasing thermal expansion coefficient for each used Aggregates.

With the help of a calculus of variations, equation (1) in Connection with equation (2) the individual volume fractions yn and the required Determine the expansion coefficient n. The calculation is simplified if the grading curve is specified as a fuller line or according to DIN 1045 and thus the volume fractions are fixed in the individual grain size ranges, so that only the expansion coefficients to be calculated as unknowns and appropriate materials to be selected.

Overall, this results in that illustrated in the diagram Structure or the composition of the additives for a synthetic resin mortar or -concrete with an expansion coefficient in the range of 12-10 6 m / mK. It is on the abscissa on a logarithmic scale in a known manner the sieve or Grain size specified in millimeters, with the between each two neighboring with numbers provided with abscissa values lying grain size range a grain size range n corresponds, iN to the same material with the according to the calculation specified thermal expansion coefficient 0 <n. On the left Ordinate is the volume fraction given in fractions of 1, so that the volume fraction Yn of a grain size range is determined in a known manner the difference between two correspondingly adjacent ordinate values results. The representation in the figure deviates from the usual representation of Fuller's lines, than the volume fraction must be used instead of the weight fraction, since in the individual grain size ranges under certain circumstances materials with different specific gravity can be used so that an indication of the percentage by weight is given could lead to significant errors. The grading curve for an exemplary recipe the course illustrated in the diagram and begins in the area of the finest grain at a value of the volume fraction that is filled by the binder, Auf the right ordinate of the diagram is the coefficient of thermal expansion « applied.

If it is assumed that the same in a respective grain size range Material is used whose coefficient of expansion differs from that in the other grain size ranges The material used is different, results in the course of the expansion coefficient as a function of the grain size ranges, the stepped shape illustrated in the diagram Course. To avoid dangerous shear stresses in the large grain area vnt that ranges from 4 to 16 mm, a material with a relatively expansion coefficients close to the expansion coefficient of the binder, for example, quartz sand is used.

Because the shear stresses with decreasing grain size for the strength of the hardened base mortar or -concrete less dangerous are, with decreasing grain size in the respective grain size ranges n < N materials with increasingly (! Lower) expansion coefficients are used, see above that the stepped course. the expansion coefficient as a function of the grain size drops in the direction of finer grain.

In order to improve the adhesion of the binder to the largest grain, can the aggregate of this area before mixing with a surfactant Agent, a surfactant, can be wetted, which later creates greater shear stresses without the risk of detachment can be included. Also a sorptive bond has a beneficial effect on the adhesive strength between the aggregate and the binder the end.

Since there may not be any inexpensive ones for the finest grain area Aggregates with low coefficients of expansion are available, it is also possible in the grading curve range below 0.5 mm, i.e. based on the figure, for the grain size ranges n = 1, 2, 3, for example, use materials with their coefficient of expansion greater than the expansion coefficient of the material for the grain size range n = 4 is.

Obvious. receives the reaction resin mortar built up according to the diagram or concrete a material composition of the fillers such that in the upper Area of the grading curves in a respective grain size range, the coefficient of thermal expansion larger than in the adjacent grain size range with a smaller grain diameter, or is smaller than in the adjacent grain size range with a larger grain diameter. the Volume fractions Yn of the individual aggregates are taken into account the volume fraction XB and the expansion coefficient of the binder such dimensioned that the resulting coefficient of linear expansion of the cured Mass is 12 10-6 m / mK.

Because the resulting coefficient of thermal expansion is not strict is linearly dependent on the parameters given in equation (1), results an actual coefficient of expansion of the hardened mass of the possibly 5 to 15% smaller than the calculated value, but this is easily achieved by a small amount Correction of the volume proportions of the individual aggregates must be taken into account can.

One reason for the difference in the actual expansion coefficient of the theoretical value lies next to the air inclusions in anisotropies of the Coefficient of linear expansion of the aggregate.

A number of recipes are given below as examples.

Example 1 Binder: epoxy resin, volume fraction 0.135, coefficient of thermal expansion 46-10 6m / mK grain range up to 0.08 mm lithium silicate, volume fraction 0.072, coefficient of thermal expansion 0.5-10-6m / mK grain range 0.1-0.3 mm fused silica and glass powder with a total Volume fraction of 0.145, of which 66 percent by volume is fused quartz and 34 volume percent on glass powder, coefficient of thermal expansion of the mixture 1.7 10 6m / mK grain range 0.7 - 1.2 mm chamotte and quartz sand with a total volume fraction of 0.166, of which 86% is chamotte and 14% is quartz sand, coefficient of thermal expansion of the mixture 4.3106m / mK grain range 2 - 5 mm granite and silicon carbide with a Total volume fraction of 0.166, of which about 50% on granite and 50% on silicon carbide not applicable, coefficient of thermal expansion of the mixture 7'10 6m / mK Grain range 5 - 8 mm granite and quartz sand with a total volume of 0.125, of which 602 duf granite and about 40% quartz sand, the coefficient of thermal expansion Mixture. -6 Grain range 8 - 16 mm split, volume fraction 0.187, coefficient of thermal expansion 11 10 6m / mK In order to reduce shear stresses when the plastic hardens, the Aggregates are also mixed with hollow microspheres, the proportion by volume of which is about 0.01 and that in the cured mass itself no expansion coefficient exhibit.

The quartz sand of the grain range 0.7 - 1.2 mm and the quartz sand of the Grain range 5 - 8 mm were pretreated with aminosilane as an adhesion promoter to improve the adhesion of the epoxy resin binder to the quartz sand.

The amount of adhesion promoter itself does not make any significant contribution to the total volume and was therefore not taken into account.

The synthetic resin concrete or mortar obtained in this way increases the coefficient of thermal expansion from grain area to grain area monotonously an and es the result is a mean calculated of which about 11.6-10 6m / mK.

Example 2 With the exception of a part of the fine aggregates increases in this example the coefficient of thermal expansion from grain area to grain area monotonous.

Methyl methacrylate binder with small amounts of chlorinated plasticizers, Volume fraction 0.130, coefficient of thermal expansion 60-10 6m / mK, grain range up to 0.05 mm of chalk and mica with a total volume fraction of 0.11, namely omitted of which 63% on chalk and about 37% on mica, thermal expansion coefficient of both Materials 8-10 m / mK grain range 0.05-0.1 mm glass powder and fused silica with a total volume fraction of 0.089, of which about 49% on glass powder and 51t on fused quartz not applicable, coefficient of thermal expansion of the mixture 2.2106m / mK grain range 0.1 - 0.3 mm quartz material and quartz sand with a total volume fraction of 0.128, of which approx 67% quartz and 33% quartz sand, the coefficient of thermal expansion is Mixture 4,3106m / mK Grain range 0.7 - 1.2 mm fused quartz and quartz sand with a total volume fraction of 0.128, of which 48% on quartz material and 51% on quartz sand not applicable, coefficient of thermal expansion of the mixture 6.5106m / mK grain range 3 - 5 mm granite, volume fraction 0.192, coefficient of thermal expansion 7-10 6m / mK grain range 5 - 8 mm granite and quartz sand with a total volume fraction of 0.192, of which approx 60% granite and 40% quartz sand, the coefficient of thermal expansion des Mixture 9.10 / 6 The quartz sand mentioned is naturally occurring Quartz sand, while quartz is melted out and crushed again with quartz material is referred to, which is largely freed from impurities in this way, in contrast to the aforementioned quartz sand.

Assuming that the mixture contains 0.033 parts by volume of air the calculated mean coefficient of thermal expansion is 13.3 10 6m / mK.

Example 3 The coefficient of thermal expansion increases with the grain range monotonous to the grain range, with aggregates in the fine grain range of 0.005-0.3 mm with a higher coefficient of thermal expansion and thixotropic properties will.

Binder methyl methacrylate, volume fraction 0.126, coefficient of thermal expansion 60 10 6m / mK grain range up to 0.005 mm thixotropic agent e.g. Chrysotil-S.erpentine Asbestos, volume fraction 0.033, coefficient of thermal expansion 9'10 6m / mK grain area up to 0.02 mm chalk, volume fraction 0.08, coefficient of thermal expansion 8.10-6 m / mK Grain range 0.1 - 0.3 mm quartz sand and quartz material with a total volume fraction of 0.098, of which 31% is quartz sand and 69% is quartz material, coefficient of thermal expansion of the mixture 4.1-10 6m / mK grain range 0.7 - 1.2 mm fired fireclay and silicon carbide with a total volume share of 0.13, 50% of which is fireclay and 50% on silicon carbide, coefficient of thermal expansion of the mixture 5.5106m / mK Grain range 2 - 5 mm dolomite rock and granite with a total volume fraction of 0.163, of which about half is made up of dolomite rock and the other half is made up of granite, coefficient of thermal expansion of the mixture 7 10 m / mK grain range 5 - 8 mm dolomite rock and quartz sand with one Total volume share of 0.163, of which about 64% on dolomite rock and 36% on quartz sand not applicable, coefficient of thermal expansion of the mixture 8.8-10 6m / mK grain range 8 - 16 mm granite and gravel with a total volume fraction of 0.206, half of that consists of granite and the other half of gravel, coefficient of thermal expansion of the mixture 9-10 m / mK.

To improve the wetting of the aggregate with the synthetic resin, a surfactant in the form of octyl alcohol is added, compared to its volume fraction however, the volume of the aggregate is negligible.

The plastic concrete or mortar obtained in this way has a medium Thermal expansion coefficients of 14.0-10 6m / mK.

Example 4 Binder polymethyl methacrylate, volume fraction 0.115, Thermal expansion coefficient 65. 10-6 m / mK particle size range 50.10 m glass microspheres with a volume fraction of 0.046, -6 thermal expansion coefficient 410 m / mK grain area Up to 0.06 mm calcide calcium carbonate, volume fraction 0.085, -6 coefficient of thermal expansion 6.10-6m / mX grain range 0.06 - 0.2 mm silicon carbide, volume fraction 0.046, coefficient of thermal expansion 7 7-10 6m / mK grain range 0.2 - 1.2 mm quartz sand and corundum with a total volume fraction of 0.226, of which 61% is quartz sand and approx. 39% is corundum, coefficient of thermal expansion of the mixture 9.7'10 6m / mK grain range 3 - 8 mm quartz sand, volume fraction 0.435, Thermal expansion coefficient 12.10 106m / m The finished mixture contains about 0.046 Volume fractions of air that can no longer be removed. The mean coefficient of thermal expansion of the fully set synthetic resin concrete or -mortar calculated up to 16.2-10 m / mK.

3 Actual Thermal expansion coefficients of 12.910 m / mK and 13.1 * 10 6m / mK measured. A test body the size 101575 cm3, manufactured according to the above recipe, resulted in a thermal expansion coefficient in the laboratory from 14.4-10 6m / mK.

The deviations in the actually measured coefficient of thermal expansion of the theoretically calculated value are a consequence of several influences, namely the sorptive binding of the binding agent to some aggregates, the binding of Air on calcite-calcium carbonate, which is strongly aerophilic, as well as anisotropies of the individual Aggregates that have different coefficients of thermal expansion in different spatial directions demonstrate.

Finally, it must be taken into account that as the test specimen becomes smaller more or less strong deviations in the composition of the aggregates from The above recipe can be expected, which translates into different coefficients of thermal expansion precipitates.

In the recipes of Examples 1 to 4 there are a number of suitable ones Materials specified for aggregates; overall, however, the following materials come into play as additives in question, in suitable proportions in the individual recipes Can be used: Material for the aggregate linear material expansion coefficient oxide-ceramic sintered products- 0.5. 10-6 m / mK te, fused quartz, special ceramic glasses, silicates of the metals aluminum, lithium and zircon as well as glass ceramic graphite, porcelain flour, 3 - 4. 10-6 m / mK ceramic Sintered materials, special glasses, fireclay flours, raw and burnt diabase, porphyry, granite, Do- 5 - 7.5 10 6 m / mK lomite, gneisses, basalts, silicon carbide, earthenware, stoneware Quartz sand and gravel, SPlit 11 - 12 10 6 m / mK - blank page -

Claims (13)

Claims 1. Reaction resin mortar or concrete1 consisting of a reaction resin as a binding agent, in the aggregates of different grain sizes are embedded as fillers, the volume fractions of the individual grain size ranges of the aggregates essentially according to a fullerl line or a grading line are dimensioned according to DIN 1045, characterized in that at least in the upper area the grading curve in a respective grain size range is the coefficient of thermal expansion the aggregates larger than in the adjacent grain size range with smaller Grain diameter or is smaller than in the adjacent grain size range with larger Grain diameter and that the volume proportions of the individual aggregates taking into account the proportion and the expansion coefficient of the binder are dimensioned in such a way that that the linear expansion coefficient of the hardened mass between 9.10 6 m / mK and 15.10 6 m / mK. 2. Reaction resin mortar or concrete according to claim 1, characterized in that that over the entire range of the grading curve in a respective grain size range the coefficient of thermal expansion is greater than in the adjacent size range with a smaller grain diameter or smaller than in the adjacent grain size range with a larger grain diameter. 3. Reaction resin mortar or concrete according to claim 1, characterized in that that the expansion coefficient is only in the grain areas below 0.5 mm of the grading curve is larger than in the grain areas above 0.5 mm of the grading curve. 4. Reaction resin mortar or concrete according to claim 1, characterized in that that in the finest grain range of the grading curve additives with a diameter of less than 0.05 mm. 5. Reaction resin mortar or concrete according to claim 1, characterized in that that the largest grain fraction of the grading curve has a diameter of at most 32 mm. 6. Reaction resin mortar or concrete according to claim 1, characterized in that that the fine grain fractions have a property that increases the viscosity of the binder exhibit. 7. reaction resin mortar or concrete according to claim 6, characterized in that that the finest grain fractions are flaky in shape. 8. reaction resin mortar or concrete according to claim 6, characterized in that that the fine grain portions have an elongated or spiral shape. 9. reaction resin mortar or concrete according to claim 1, characterized in that that the finest grain fractions of the aggregate the. Binder sorptively binding fractions exhibit. 10. Reaction resin mortar or concrete according to claim 1, characterized in that that to bind air and to improve the shrinkage behavior during curing of the mass, the finest fillers are aerophilic. 11. Reaction resin mortar or concrete according to claim 1, characterized in that that the aggregates of the largest grain range have a near coefficient of expansion of the binder have thermal expansion coefficients. 12. Reaction resin mortar or concrete according to claim 10, characterized in that that the additives of the largest grain range have a coefficient of expansion of have about 12,106 m / mK. 13. Reaction resin mortar or concrete according to claim 1, characterized in that that a respective grain size range from aggregates with different expansion coefficients consists.