CS272728B1 - Carburizing agents - Google Patents

Abstract

The subject of the invention is an additive for cement mixes with increased firmness of final products, containing 10 to 90 % by weight of products of formaldehyde with higher aldehydes and ketons and 5 to 90 % by weight of lignosulphonates, which can be original or microbiologically and/or chemically modified, possibly containing a deaerating agent.

Description

The present invention relates to a novel additive for cementitious mixtures based on ligninstilphonates with increased strengths of the final products.

Lignin sulphonate-based additives are characterized by a plasticizing effect on the processing of cement mixtures with a partial retarding effect on the increase in strength during the initial period of concrete setting and hardening (T. Sebók: Additives and Additives for Mortars and Concrete, SNTL Prague 1985; K. Šestanber: Paper and pulp) 40 (10, 213 (1985)) The optimum dose of these additives is 0.1-0.3% by weight of dry matter per weight of cement, while the strength at least is at the level of the comparative samples. Retarding is caused by the aerating effect of the additive, ie a high content of surfactants as well as substances reacting with the cement components, which slow down to prevent the hydration and crystallization of the cement components (Cement and Concrete Research, Vol. 13). , pp. 830-842, USA, Pergamon Press (1983)).

These effects are counteracted by de-aerating agents. A0 166 965), as well as by removal of the carbohydrate moiety by microbiological (Cs. PV 8172-83) or chemical route (Cs. PV 4619-86).

Although these processes have largely eliminated the retarding effects of impurities in the lignosulfonates, the day-to-day strengths of the cementitious compositions are still considerably lower by 2 to 10 times than without these additives.

These drawbacks are overcome by the cementitious additive according to the invention, based on lignin sulphonates with increased strengths of the final products, which contains 10 to 95% by weight. % of formaldehyde condensation products with other aldehydes and ketones formed in the production of di-polyols in the form of their aqueous solutions and 5 to 90 wt. The ligninsulfonates, whether original or microbiologically or chemically modified, may be added with deaerating agents.

The advantage of using the additive according to the present invention is that, with the high plasticizing effect of the additive, one-day and three-day strengths are substantially increased. In addition, even strengths after 28 days are demonstrably higher than in comparative samples without this additive.

The application of this additive is according to its composition. In the case where the additive consists of approximately 50% sodium or calcium ligninsulfonates with microbiologically and chemically removed carbohydrates and about 50% of the treated mother liquors from the production of dl to polyols e.g. pentaerythritol, then application of 1 wt. additives in terms of dry matter and cement in the cement mix appear to be very advantageous in terms of strength. When using an additive containing 90% lignin sulphonates, it is preferable to use lower doses, with the original lignin sulphonates in an amount of 0.1 to 0.3% by weight. (max.), in case of microbiologically degraded resp. the chemically reduced sugar content of the lignosulfonates may be 0.3 to 0.6% by weight. cement dry matter in cement mixtures.

With a content of 10% lignin sulphonates in the mixture, the dose may be increased to 2-3% of the dry matter content of the cement in the cement mixtures. The optimum dose in terms of plasticizing effect on cementitious compositions is the use of higher amounts of lignin sulfonates. By using a greater amount of formaldehyde condensation products, in turn, higher cementitious strengths are achieved.

An application of 50% by weight has proved to be good in application tests for good plasticizing effect and at the same time high strengths. % lignosulfonanom and 50 wt. treated mother liquors from the production of formaldehyde-based di to polyols.

The application of the additive is suitable together with the mixing water. When an excess of lignin sulfonates is used, it is advisable to apply surfactants with a defoaming, deaerating effect to reduce the air content of the cementitious compositions. In the case of excess condensates from formaldehyde, this addition also reduces the air content of the cementitious mixtures.

WITH?

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CS 272728 Bl

The advantage of applying the ingredients of the present invention is that they are achieved by applying them! good plasticizing effects and high strengths, while the raw materials for their preparation are widely available. At the same time, the application means a substantial increase in the strength of the concrete mixture, respectively. saving cement while maintaining the required strengths achieved with admixture-free cement.

The effects achieved with the additives of the present invention are shown in the following examples, but they do not exhaust all possible combinations of use.

Example 1

Effect of amount and type of dry matter additive on cement, namely lignin sulphonate additive of biodegraded SF plastic, formaldehyde condensates with other aldehydes (Pemral), biologically and chemically degraded lignin sulphonate (PRH ligoplast), mixture of PRH and PEMRALU 1: 1 ligoplast, ligoplast PEMRALU 1: 1 PM (Ligoplast Na 10% + 90% PEMRAL), (Ligoplast SF + PEMRAL 1: 1) Ligoplast SFP, Ligoplast Na, in the presence of various defoamers (deaerators), are summarized in Table 1.

Tests were performed on concrete mixes according to ON 72 2320 with cement SPC -3 -3

325 Wet 300 kg. m; sand 0 - 4 mm Hulín 820 kg. m, grit 4 - 8 mm Olbramovice 365 kg. m ³ ; grit 8 - 16 mm Olbramovice.

The water was dosed in such a quantity as to obtain a workability of 60-10 mm cone settling.

Table 1

Influence of type and quantity of additive on plasticization of concrete mixtures and compressive and flexural strength.

no. samples additive dose dry matter for cement [% w / w] Water Ll.ni- ³ ] Compressive strength [MPa] strength in turn bending [MPa] 7 days 28 days 1 ' without additive 0 212 6.3 15.0 2.67 2 Pemra 0.25 200 12.8 21.0 3.32 3 PEM ligoplast 0.50 178 15.9 25.8 3.58 4 PEM ligoplast 1.00 172 17.9 30.8 4.18 5 ligoplast PM 0.25 186 11.2 22.6 3.09 6 ligoplast PM 0.50 172 17.1 27.8 4.37 7 ligoplast SFP 0.50 178 17.0 28.2 4.23 8 ligoplast SFP 1.00 172 18.9 32.9 4.50

Example 2

The cement slurry was prepared from SPC - 325 Horni Srnie cement by manual vigorous stirring for 3 minutes. Normal density was determined according to ČSN 72 21 15. The produced slurry was filled into steel molds of cylindrical shape of 40 mm diameter and 40 mm height, attached by plastic to a glass support. The batches were made with 400 g of cement.

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CS 272720 Bl

The plasticizing additive used was thickened ligoplast, biologically degraded ligoplast (Na ligoplast), biodegraded and chemically treated (PRH ligoplast), in combination with the pemral type aldehyde condensates (mixture of pentaerythritol, pentaerythritol formaldehyde formates and formaldehyde condensates) deaeration additives (higher fatty alcohols, ethoxylated derivatives of higher alcohols (A), acids or polyadducts ethylene and propylene oxide (S)).

The results are summarized in Table 2.

T a b u l 'k a 2

Effect (0.7 wt.% Dry weight) of additive on cement weight in lignosulfonate based cementitious compounds on plasticizing efficiency and compressive strength. Cement 400 g, SPC - 325 Horni Srnie, Water 121.5 ml / 400 g cement - 100%.

no. samples sample dose waters w strength in pressure for 1 day [MPa] beginning Pour Eh] time Pour [H] 0 comparative 100 17.77 4.5 5.3 1 PRH ligand 81.4 1.03 2.3 4.6 2 ligoplast + A 81.4 2.52 1.75 3.25 3 PRH + pemral ligoplast 1: 1 83.1 12.56 1.8 4.15 4 ligoplast Na 81.0 0.32 2.0 4.0 5 Na + A ligoplast 81.4 0.55 3.0 5.0 6 Na pemral ligoplast 1: 1 83.1 10.07 2.0 4.3 7 ligoplast Na pemral 1: 1 defoamer S 82.2 15.4 1.5 4.0 8 ligoplast Na 1 pemral 0.5 Na acid salts ^c r ^c 6 ° ⁵ 83.5 17.7 3.3 6.25 9 ligoplast Na 0.1 pemral 0.9 90.0 20.0 4.0 5.0 10 ligoplast Na 0.9 pemral 0.1 81.0 3.0 2.1 4.0 11 ligoplast 81.0 0 2.3 24.0 12 ligoplast 0,1 pemral 0,9 90.0 13.0 4.3 5.5

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Example 3

The effect of addition of aldehyde condensates of pemral type and ligninsulfone mixtures on plasticization efficiency and strength of concrete mixtures was studied. Concrete mixes were prepared using PC 400 cement from Ladce cement plant in an amount of 300 kg. m ^- ^ concrete mixture. Naturally drawn Danube aggregates with a composition of 0 - 1 mm 23.8% were used as feed; 1-2 mm 12.1%; 2-4 mm 12.1%; 4-8 mm 20%; 8-16 mm 32%. The concrete mixture was agitated for 3.5 minutes in a 125 L gravity mixer. After compacting in steel molds on a vibratory table for 30 seconds, 10 cm cube strengths were monitored after 1.7 and 28 days hardening. The results are summarized in Table 3.

T a b u Γ k a 3

Concrete mixture with 0.7 wt. PC - 400 cement dry matter

no. test sample Total mixing water [lm- ³ ] slump cone [Mm] Contents air w Compressive strength [MPa] 1 day 28 days 0 comparison 172.5 55 2.0 6.0 30.1 1 ligoplast Na 153.4 50 5.7 0.0 29.8 2 PRH ligand 143.5 60 8.4 0.0 28.3 3 PRH + A ligoplast 157.5 50 1.4 0.8 31.6 4 PRH ligand -1.0 pemral -1.0 + S 167.4 50 1.8 1.0 33.6 5 Ligoplast Na 1 pemral 0,5 alkali salts of C.-C 0,5 0.5 165.1 50 2.5 4.2 31.5 6 Ligoplast Na 1 permal 1 defoamer S 167.9 55 2.7 2.4 39.9 7 Ligoplast Na 1 pemral 1 166.3 50 5.0 3.1 37.9 8 Ligoplast Na 1 pemral 0,1 defoamer A 0.01 165 50 2.0 0.0 38.4

Example 4

If the addition was prepared from a 10% sulphite liquor, the aldehyde condensates from the production of trimethylolpropane resp. neopentyl glycol, the cement in the concrete mix according to the procedure of Example 1, 180 l was needed. m 2 of the mixing water, achieving a compressive strength of 21 MPa / 7 days and 34 MPa / 28 days and a bending tensile strength of 4.91 MPa.

Claims (1)

OBJECT OF THE INVENTION Additive to cementitious mixtures based on ligninsulfonates with increased strengths of final products, characterized in that it contains 10 to 95 wt. % of formaldehyde condensation products with higher aldehydes and / or ketones resulting from the production of di-polyols and 5 to 90 wt. Liginsulfonates, whether flooded or microbiologically and / or chemically treated, may optionally be added with deaerating agents.