Classifications

• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B24/00—Use of organic materials as active ingredients for mortars, concrete or artificial stone, e.g. plasticisers
  • C04B24/16—Sulfur-containing compounds
  • C04B24/18—Lignin sulfonic acid or derivatives thereof, e.g. sulfite lye

Definitions

• the present invention relates to utilization of alkylated lignin products as adjuvants in cement, mortar, and con ⁇ crete.
• the invention especially relates to utilization of alkylated lignin products as s.c. super plasticizers in concrete.
• the invention relates to utilization of alkylat ⁇ ed lignin products as combined plasticizers and air intro ⁇ ducing substances in concrete.
• Plasticizing or super plasticizing adjuvants for concrete are used in concrete, either to reduce the need of water or to enhance the processability or flow.
• the produced concrete is easily processed or has good flow properties.
• Concrete for pumping and gunite are examples of concrete where good flow properties are important.
• flow concrete that should be self compress ⁇ ing, i.e. casting should be possible without compressing the concrete by vibrators or in another manner. It is. thus, possible to use flow concrete in cases where reinforcement bars are closely arranged or where the space to be filled with concrete has a shape preventing access for a vibrator.
• a combination of good flow properties and a reduced water addition might be desirable.
• An example to be mentioned is the production of concrete elements in a factory. In that case a moderate cement dosage, high strength and mo ⁇ derate vibration are desirable. The last mentioned measure has the purposeof reducing bothersome noise in the factory.
• Air introducing adjuvants are used to increase the content of finely distributed air in the concrete. It is well-known that concrete with an increased content of finely distribut ⁇ ed air is more resistant to frost, i.e. it has an improved capability of standing freezing and thawing.
• an air introducing adjuvants has also a water reducing e ect. This is due to the fact that the finely distributed air acts as a lubricant and, thus, improves the flow of the concrete. In most cases, however, it is possible to reduce the demand for water additionally by adding a water reducing adjuvant. Combinations of water reducing and air introducing adjuvants are usually utilized to day.
• Lignosulphonates have been used for many years as plasti ⁇ cizing or water reducing adjuvants for concrete. Said lignosulphonates are, to day, used in concrete in amounts up to approx. 0.2% " dry substance, on the basis of cement in the concrete. With higher amounts the lignosulphonates to some extent start to have an ef ect that retards setting. In cases where high strength is necessary at an early stage, e.g. because formwork has to be removed, such admixture, thus-, must not exceed 0.2$.
• Said super plasticizing adjuvants when used in the same relative amounts, usually, have no more water reducing effect than the lignosulphonates.
• Super plasticizing adjuvants can, thus, be added in larger amounts than the lignosulphonates, and that permits the achievement of a considerably larger water re ⁇ duction in concrete than with the lignosulphonates.
• Generally used amounts of super plasticizing adjuvants are approx. 0.5% dry substance, based on the cement content of the concrete. In some cases additions of up to approx. 1.0% may be used.
• Lignosulphonates as well as naphtalene- and melamine com ⁇ positions are used, to day, together with air introducing adjuvants in the production of frost-resistant concrete.
• Conventionally used air introducing adjuvants are resin derivatives, fatty acids and surface active compositions.
• the present invention relates to the utilization of alkylated lignin products in cement, mortar,and concrete.
• Lignin products here comprise products derived from so called sulphite, sulphate and alkali waste liquor.
• waste liquor It is characteristic of all these kinds of waste liquor that their main components are materials containing lignin , but that they, additionally, contain carbohydrates, low-molecular organic compounds, and inorganic salts.
• the waste liquor is obtained from the production of cellulose from lignin - cellulose containing material by known methods.
• a sulphite process is characterized by the fact that a. liquor containing sulphite and a base that may be Ca, Na, Mg, or NH ⁇ is used in sulphite cooking.
• the waste liquor after cooking will then contain Ca-, Na-, Mg-, or NH,-lignosulphon ⁇ ates respectively.
• the lignosulphonate proportion of the sulphite waste liquor can be increased by complete or partial removal of the carbo-
• Carbohydrates may e.g. be prefermented and, thus, form the basis of an ethanol production.
• Ca-lignosulphonates may in a known man ⁇ ner form the raw material for the production of Na-, Mg-, NH 3 ⁇ , Fe- and other metal lignosulphonates.
• alkali processes aqueous solutions of NaOH are used as cooking liquids, whereas the cooking liquids in sulphate processes contain Na «S in addition.
• alkali- and sulphate processes the waste liquor is often burned for recovery of energy and chemicals. In some cases, however, these waste liquors are used as raw materials for the production of alkali- and sulphate lignin . respectively.
• waste liquor in this context also includes so called oxylignin waste liquors.
• This may e. g. be a waste liquor from the production of vanillin by oxy- dation and alkali processing of the sulphite waste liquor. It may also e.g. be a waste liquor from oxygen bleaching of lignocellulose material.
• lignosulphonates alkali-, and sulphate-, and oxylignin, modified in a number of ways that are well-known to those skilled in the art of lignin process- ing, may be used as raw materials.
• alk lation can be carried out with a number of alkylation agents in aqueous as well as or ⁇ ganic solvents.
• alkylation agents in an aqueous environment may e. g. be dimethyl- or diethyl sulphate.
• the dry substance concentration of the lignin products during alkylation may be between 5 and 60%, preferably between 30 and 55%.
• the pH during alkylation should be higher than 7, preferably between 8 and 12.
• the amount of alkylat ⁇ ion agent will depend on the selected agent. If dimethyl- sulphate is selected, 1-50%, based on waste liquor dry sub ⁇ stance, and preferably 20 to 30% are used.
• the temperature during alkylation may be between 0 and 200°C, preferably between 10 and 100°C.
• Alkylation causes the properties of the lignin products to change substantially when used in concrete.
• alkylated waste liquor products are made considerably less retarding to setting.
• these products are made more air introducing.
• Suitable dampers may e.g. be tributylphosphate, n-butylcarbonate, aliphatic alcohols or fatty acid esters.
• the alkylated waste liquor products By using the alkylated waste liquor products alone, products are obtained that have an air introducing as well as water reducing effect. When used in amounts that are of interest to achieve a full water reducing effect, said products may in certain cases have a too strong air introducing effect. In these cases the air content of the concrete may e.g. be adjusted by an addition of small amounts of dampers.
• alkylated lignin products were found to introduce air that was very stable in the concrete. In mixtures with dampers alkylated lignin products also resulted in consider ⁇ ably more stable air than achievable by combinations of air introducing and plasticizing/super plasticizing substances conventionally used to day.
• Alkylation of lignin products is previously known.
• alkylation is e.g. used in combination with other processes to reduce the natural color of the lignin products.
• Alkoxylation agents are very explosive and, thus, difficult to handle. In most cases, alkylation will, thus, be preferable to alkoxylation.
• Alkylated lignin products according to the invention can be added to cement, mortar, and concrete in amounts up to 2.0%, based on cement, preferably from 0.1 to 0.8%. The addition may be made to the cement when mortar or concrete are mixed, or to the finished mortar or concrete mixture.
• Alkylated lignin products according to the invention may al ⁇ so be added to so called pozzulans, e.g. flue dust and silica, which are then admixed with cement, mortar, and con ⁇ crete. The products may also be added in mixtures with other additives.
• the following example illustrates how the setting retardation effect of lignin products may be reduced by alkylation.
• the alkylation was carried out in a 5-necked round flask provided with inter alia a mixer and a reflux cooler. The solutions were heated to 60°C. Whereas the pH was main ⁇ tained at 10 by addition of 45% NaOH, dimethylsulphate, 30% based on waste liquor dry substance, was bled into the sol ⁇ utions in the course of one hour.
• the solutions were left standing at least another hour at 60°C before they were spray dried.
• the setting retarding effect of the lignin product was tested in cement slurries. Standard Portland cement from Norcem, Norway was used. The stated amount of thelignin product was dissolved in 75.0 g of water and 300 g cement were added. As a blind test 300 g of cement and 90.0 g of water were used. The mixture was kneaded for 2 minutes with a spoon and sub ⁇ sequently placed in containers.
• the containers were placed in a calorimeter and the develop ⁇ ment of temperature was monitored by the aid of thermoele ⁇ ments and a printer.
• the initial setting time is noted as the time lapsed for the temperature to raise above 40°C.
• the concrete was mixed in a 60 1 free fall mixer. A fixed mixing time was used.
• the concrete had the following composition:
• the sinking measure is at first maintained approximately constant, while the reduction of the water demand is utiliz ⁇ ed to achieve a concrete with increased strength.
• the same concrete mixture and mixing conditions as in Example 2 are used, but the addition of water was selected so as to main ⁇ tain the sink value of approx. 15 cm.
• Consistency and air were measured as in Example 2. Initial and finished setting was measured in cemented glue, consist ⁇ ing of adjuvants, water, cement and sand as described in DIN 1164. The compressive strength of the concrete was mea ⁇ sured according to Norwegian Standard 427A, Part 2, Page 1 and Pager 5.4. The w/c ratio is the ratio between water and cement in the concrete.
• Adjuvant / w/c % Setting time Compressive strenc ⁇ th N/mm 2 dosage ratio air Initial Finished 3 days 7 days 28 days
• the water addition to the concrete was kept constant, i.e. the tests were made with a constant w/c ratio.
• the 0 concrete mixtures consisted of 6.0 kg cement, 23.0 kg sand, and 19.0 kg shingle.
• the adjuvants were dissolved in 4.6 kg water and added to the mixer at the end.
• the mixing con ⁇ ditions were as in Example 2.
• the consistency was measured according to Norwegian Standard 427A, Part 2, Page 5.1.4. 5
• Table 5 shows the consistency of the concrete mixture af ⁇ ter 10, 30, 60, and 90 min. as measured after finished mixing. It appears that "Borrecem SP" yields as good an im ⁇ provement of the concrete consistency as the commercial 0 super plasticizing substances.
• Example 3 This example will illustrate how "Borrecem SP" having a composition as in Example 3 results in an improved early strength as compared with non-alkylated lignosulphonates.
• the same concrete mixture and mixing conditions were used as in Example 2.
• the setting of the concrete mixture was deter ⁇ mined by measuring penetration resistance as stated in ASTM C403-80. Cubes were cast as described in Norwegian Standard 427A, Part 2, Page 1 and Page 5.4. The cubes were stripped immediately before pressure testing.
• the air content was measured as in Example 2.
• the stability of the air in the concrete was determined by securing the air meter to a vibration table.
• the vibration u table being a part of the so called ⁇ Vebe-meter used for measuring the consistency of concrete was used.
• the concrete in the air meter was vibrated for predetermined periods and read in the conventional manner.
• a commercial air introducing adjuvant was used in the tests.
• Said adjuvant is here called an L-substance.
• “Borrecem LP” yields a substantially less stable air content than achieved by combinations of air introducing and plasti ⁇ cizing/super plasticizing substances, and a correspondent water reduction is achieved at the same time.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Ceramic Engineering (AREA)
• Materials Engineering (AREA)
• Structural Engineering (AREA)
• Organic Chemistry (AREA)
• Curing Cements, Concrete, And Artificial Stone (AREA)

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• 1982
  • 1982-11-10 NO NO823752A patent/NO823752L/no unknown
• 1983
  • 1983-11-02 WO PCT/NO1983/000046 patent/WO1984001943A1/en unknown
  • 1983-11-02 EP EP83903318A patent/EP0126091A1/en not_active Withdrawn

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