RU2039717C1 - Raw material for manufacture of sawdust concrete blocks - Google Patents

Abstract

FIELD: manufacture of building materials. SUBSTANCE: raw material for manufacture of saw- dust concrete blocks includes, mas.part. wood-particle aggregate 50-55; mineral aggregate 16-20; portland cement 20-25; water 4-10; potassium 4- chloro-2,3,5,6-fluorophenolate 0.05-0.10. Mixture may contain up to 4 mas. part. of gypsum. Wood-particle aggregate is used in form of sawdust, chips, bark. Mineral aggregate is used in form of sand, gravel, cinder wastes of thermoelectric plants, and boilers. Addition of potassium 4-chloro-2,3,5,6-fluorophenolate ensures resistance of finished products to mold fungi and makes them practically incombustible. Blocks made of offered mixture feature good heat insulation and are easily workable. Mixture is prepared from readily available raw materials. Manufacture process of blocks is simple and needs no complicated equipment. EFFECT: higher efficiency. 2 cl, 1 tbl

Description

 The invention relates to the technology of building materials and can be used in the manufacture of sawdust blocks intended for the laying of external walls, internal partitions of buildings, etc.

It is known that a building material made from a raw material mixture based on crushed wood waste (in particular sawdust), cement and water and having initially high strength characteristics is rapidly destroyed, mainly due to the formation of reconstituting water-soluble sugars (cement poisons). Restoring water-soluble sugars, products of the action of enzymes of mold-wood-destroying fungi interact with calcium, selecting the latter from cement (Ca ₂ SiO ₄ , Ca ₃ SiO ₅ , Ca ₃ (Al ₂ O ₃ ) ₂ ). This process reduces the curing rate of cement and the strength of the finished product.

 To exclude the formation of reducing sugars, it is necessary: to accelerate the curing process of the raw mixture; to increase the biostability of wood-cement products by treating the wood aggregate with a chemical compound as an antiseptic with a pronounced fungicidal effect.

 The most famous combinations of additives for wood aggregates are mixtures of calcium chloride with water glass and calcium chloride with aluminum sulfate, a mixture of lime with calcium chloride, aluminum sulfate with ammonium nitrate, calcium hydroxide with ammonium carbonate.

 All these additives are introduced into the raw material mixture in order to accelerate the curing process and increase the strength of the products. Their side effect is the mineralization of wood, which increases the biostability of finished products. To increase the biostability of the material, an antiseptic chemical compound with a fungicidal effect is additionally introduced.

 Known raw mix for the manufacture of heat and sound insulating material containing wood fiber, paraffin emulsion, aluminum sulfate, expanded perlite, water, and sodium pentachlorophenolate as an antiseptic. However, this mixture is suitable only for interior construction work.

Closest to the claimed technical solution is a raw construction mixture, which contains, by weight. Portland cement 30-40
Wood filler 5.53-7.8
Mineral filler 32-40
Bi-substituted ammonium phosphate 0.02-0.2
Sodium tetraborate 0.03-0.3 Water Else
In the proposed mixture, a wood waste fraction of 0.5-10 mm is used, which is obtained by sifting through a sieve with a hole diameter of 10 mm and a residue on sieves with a hole diameter of 0.5 mm. With large inclusions in the fabricated material, shells, cracks and voids are observed, which leads to deterioration of strength. In addition to wood waste, the composition of the prototype introduced wood flour, the composition of which is strictly limited (0.03-0.3%). The maximum particle size of wood flour used in the proposed mixture is 0.2 mm

 Wood flour in the mixture prevents the aggregation of Portland cement particles during the preparation of the molding mixture from the mixture. For use in the preparation of this mixture, a certain moisture content of wood waste and wood flour is required not higher than 5%. At higher humidity, very small wood particles clump together, making mixing difficult, which leads to an uneven distribution of particles and reduces the strength characteristics of products made from this mixture .

 As an additive, the prototype mixture contains phosphate disubstituted ammonium (0.02-0.2 wt.) And sodium tetraborate (0.03-0.3 wt.). These additives perform (have) a defibrillating effect, which provides free access of water to Portland cement particles during its hydration. In addition, these additives give products flame retardant properties.

 Despite these advantages, the composition proposed by the invention has significant drawbacks, namely: it requires careful preliminary screening of wood flour and chips with the selection of narrow fractions. Their humidity is strictly limited, and therefore, when the specified limit is exceeded (5%), an additional stage of drying the raw material is required.

 In addition, as follows from the above quality indicators, the products obtained from such a mixture have a relatively high mass (density).

 The purpose of the invention is the creation of a mixture for the manufacture of sawdust concrete blocks with high strength characteristics, convenient to operate and at the same time easy to manufacture.

The essence of the proposed technical solution is that as a raw material mixture for the manufacture of blocks using a mixture containing Portland cement, wood aggregate, gypsum (and without it), antiseptic 4-chlorine, 2,3,5,6-fluorophenolate (CTFPC) and water in the following ratio, wt. Portland cement 20-25
Wood filler 50-55
Mineral Fill
carrier (e.g. sand) 16-20
4-chloro, 2,3,5,6-fluorophenolate potassium 0.05-0.10 Water 4-10
The mixture may contain up to 4 wt.% Gypsum.

 As a wood filler, waste from processing any wood species, sawdust, shavings, pre-chopped branches and bark is used.

Mineral aggregate is sand with inclusion of clay particles of not more than 5-10% of pre-ground ash ash from fuel (slag) of thermal power plants and boiler houses. To accelerate the curing process, especially at temperatures below 15-16 ^{° C,} the mixture is introduced into the plaster (CaSO _4, 0,5 H ₂ O) or gypsum xCaSO _4˙ yCaO.

As an antiseptic in the treatment of wood-based waste, an aqueous solution of 4-chloro, 2,3,5,6-tetrafluorophenolate potassium (CTFPC) is used. This substance is less volatile and less toxic than sodium pentachlorophenolate. HTPC is chemically resistant, does not burn, it is highly soluble in water, has the ability to penetrate into the deeper layers of wood, has a high fungicidal activity at low concentrations of 0.005-0.05 wt. According to the proposed method, the manufacturing process of sawdust concrete blocks includes three main stages:
pre-impregnation of sawdust or other wood waste in any container (depending on performance), for example in a bath, with an aqueous solution of CTFPC for 3-5 hours at a temperature of 20 ± 5 ^о С.

loading into a concrete mixer wood waste impregnated with an aqueous solution (sawdust, shavings or chopped branches and bark), sand (or slag), Portland cement, gypsum, water and mixing for 30-40 minutes;
molding of finished products in typical molding vibroinstallations (type IBK-01, manual mobile or SV-250, mobile) or any other similar in action.

After molding blocks are released when moving and installation molding are left in place for 12 hours at a temperature of 20 ± 5 ° ^C. After this time the unit dials enclose about 40% of the desired strength and stored. After 24 hours, finished blocks can be transported.

 Examples of compositions, their operational and technical characteristics, comparison with the prototype are shown in the table. All formulations are prepared by the method described previously. The characteristics of the finished products are determined similarly to the prototype at the age of 28 days.

 From the presented experimental data it can be seen that sawdust concrete blocks are a building material, convenient for the construction of a personal compound. All blocks of approximately 14-15 kg with dimensions of 390 x 190 x 190 mm replace seven standard bricks. The material has good thermal insulation (coefficient of thermal conductivity 0.10 0.12), can be easily processed by manual and mechanical cutting tools. In strength it is close to the grade of brick M75, in frost resistance to the grade of brick Mrz 50.

 The manufactured blocks were subjected to an additional fire hazard test: 5 blocks were doused with diesel fuel and set on fire. After attenuation of the flame burnout is not marked. Their slight cracking was observed. Thus, the proposed building material refers to refractory. The use of affordable local raw materials and waste from woodworking industries that practically do not require additional processing simplifies the process of manufacturing sawdust concrete blocks. This helps to reduce their cost without compromising performance.

Claims (1)

 1. RAW MATERIAL MIXTURE FOR THE PRODUCTION OF SILVER-CONCRETE BLOCKS, including Portland cement, wood and mineral aggregates, additive and water, characterized in that it contains 4-chloro, 2,3,5,6-potassium fluorophenolate as an antiseptic additive in the following ratio of components parts by weight Portland cement 20 25
Wood Aggregate 50 55
Mineral aggregate 16 20
4-Chlorine, 2,3,5,6-potassium fluorophenolate 0.05 0.10
Water 4 10
2. The mixture according to claim 1, characterized in that it additionally contains up to 4 parts by weight gypsum.

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