JPS6023475A - Soil-hardening agent - Google Patents

Abstract

PURPOSE:To provide the titled soil-hardening agent which is an alkaline mixture obtained by adding less than specific amount of a cobalt chloride complex compound to an aqueous solution of an alkali metal salt, and gives a hardened soil having excellent strength and elastic modulus and resistant to cracking when used in combination with cement. CONSTITUTION:The objective agent is a mixture having alkaline nature (preferably 9-12pH) and obtained by adding <=4(wt)%, preferably 0.1-0.5% cobalt chloride complex compound (preferably a cobalt chloride ammine complex compound produced by the reaction of ammonium chloride, an alkali metal carbonate, cobalt chloride and oxygen) to an aqueous solution of an alkali metal salt (preferably a combination of sodium carbonate, potassium carbonate and sodium chloride).

Description

[Detailed description of the invention] The present invention relates to a soil hardening agent.

Many patents and documents have been published regarding conventional soil hardening agents, but most of them are based on sodium silicate (hydraulic lath), which uses an injection method, and there are no patents on soil hardening using mixing or other methods using chemicals. Relatively few. When performing soil treatment, since chemical solutions do not have the ability to harden or solidify by themselves, it is natural to consider using cement, which is easy to handle and has high strength, as a solidifying agent. Patent No. 833570 can also be said to be an example. That is, this patent is characterized in that when hardening soil with cement, ammonium salts are fused (or added) to an aqueous solution of alkali metal salts and alkaline earth metal salts. Looking at the examples, strong acid salts such as aluminum chloride and ferric chloride were used, and in fact, the mixed solution of Example 1 was 25
°C according to the recipe prepared by the inventor and measured at a site where the pH was 4.0, and in Example 2 the pH was 1.8. Further, ammonium chloride is also used in a fairly large amount of 10 to 15% by weight in the total liquid. Regardless of whether this is true or not, the inventor is Xun Kumo 3
The normal hardening process of hydration → setting → hardening of cement, which is mainly composed of CaO・SiO□ (tricalcium silicate), progresses in strong alkalinity due to the large amount of Ca(OH)2 (calcium hydroxide) generated during irrigation. From the fact that shows the final hardening strength over time, adding such a strong acidic solution is not favorable for the normal hardening of cement due to its rapid setting, and adding a large amount of chloride is not good for cement, let alone soil. Of course, Cement 1 produces a large amount of Ca1l2 (calcium chloride) through double decomposition, which is not desirable after hardening because it is a solubilized substance.Also, the strength of Cement 1 after hardening is due to the large surface energy of the fine crystals of cement gel. They coagulate and intertwine with each other to form a dense network structure, which strengthens the bonds and progresses in hardening, developing strength. At that time, the cement water use product is 20
Because they are microscopic particles with a large specific surface area of 0rn'/H, the intermolecular attraction is strong because they exist in close proximity to each other, and the chemical bonding force due to hydrogen bonding and charge imbalance is ten times stronger than this force. is added to indicate strength. From this perspective, it can be inferred that the city that adds a strongly acidic mixed solution places too much emphasis on the soil, but on the other hand, it disturbs the normal hardening of the cement and may not be able to obtain sufficient strength. That is, local aggregation or coagulation occurs, and since this is instantaneous, the result is completely opposite to normal curing, which has an extremely dense network structure. Based on the above facts, the present invention is a large book in which the mixed chemicals are adjusted to always maintain the alkaline side in order to correspond to the normal hardening process of not only soil but also cement, which holds the biggest key to solidification and hardening. It is a characteristic. Before conducting a mechanistic analysis of the present invention, the types of drugs compatible with the present invention will be described.

The alkali metal salts include at least one kind of salts such as carbonates, bicarbonates, chlorides, and hydroxides such as potassium, sodium, and lithium, which are soluble in water or are soluble in water within a certain solubility range, and these salts may be used singly or The mixture must be a completely aqueous solution and must always remain alkaline even if less than 4% by weight (based on the total liquid) of the cobalt chloride complex compound is added. It was confirmed that the most effective combination of sodium carbonate, potassium carbonate and sodium chloride was found to be most effective. Of course, other salts mentioned above are also effective in the present invention. or,
In order to further enhance the effect of the alkali metal salt aqueous solution or to meet special needs, alkaline earth metal salts (including water-insoluble substances) may be added or other additives may be added as long as the main purpose of maintaining alkalinity is not impaired. There is no problem with adding substances. The present inventor investigated transition metal elements to have a synergistic effect with the above-mentioned alkali metal salts and the effects of the present invention, and found that the effects,
It has been discovered that a complex compound of cochloride/Held is the most effective in terms of stability, quick drying, and other aspects. A mixed aqueous solution of sodium chloride, soda carbonate, and potassium carbonate containing ammonium chloride cures too quickly for the purpose of the present invention, and the cured product has the disadvantage of being brittle. When made into a complex compound, the curing time falls within an appropriate range and a highly strong cured product with no brittleness is produced. On the other hand, when ammonium chloride is removed and cobalt chloride is added, liquid phase separation occurs instantaneously, which does not satisfy the intended purpose in terms of performance, but when ammonium chloride is added, a stable aqueous solution is created, which meets the wood's purpose. I learned what to do.

As a result of various experiments, the inventor of the present invention found that the amount of the cobalt chloride complex compound in the total solution is 4% by weight or less, preferably 0.1 to 0.0%, based on stability, curing speed, strength, economical aspects, etc.
The amount is 5% by weight, and if it exceeds 4% by weight, the effect of increasing strength and curing speed will not be sufficient to warrant addition, and it will become uneconomical. The coherto chloride complex compound according to the present invention is believed to be a cobalt chloride ammine complex compound produced by a reaction with ammonium chloride, an alkali metal carbonate, cobalt chloride, and oxygen; in this case, the amount of ammonium chloride required for the complex compound is Theoretically, it is the same amount as the complex compound, but it is also quite conceivable that it will be consumed in the reaction with calcium hydroxide generated during the cement O hydration reaction, so it is necessary to add more than the theoretical amount. However, if the amount is too large, a large amount of undesirable water-soluble calcium chloride will be produced due to the reaction with hydroxide lithium as mentioned above, so at least in the early stage of four-combination, the cobalt chloride complex compound should be given top priority. Since it is important to form a
．． Around 5 times seems appropriate. Therefore, the amount of ammonium chloride used in the above-mentioned optimum range is 0.3 to 1.5% by weight. 10-15% by weight in total liquid
The amount of ammonium chloride used in the present invention is too small compared to that used in the present invention, and the solution pH in the present invention is all 7 or more, preferably 9 to 12, whereas the patent The pH of the solution is strongly acidic, ranging from 4.0 to 1.5, and in the case of the present invention, the reason for the existence of a cobalt chloride complex compound is completely different from that of the patent, since cars, etc. have this feature. I understand something.

When using the aqueous solution of the present invention to harden soil together with cement, it is effective to use aggregate, soil, organic consolidation agents, hardening accelerators, and other additives, as long as it does not violate the purpose of the tree. . The present inventor speculates as follows about the mechanism by which the present invention cures and obtains satisfactory strength in the presence of a cobalt chloride complex compound.

Carbonates in the ingredients remove organic substances contained on and inside the soil, such as oils and fats, and at the same time disperse them in water in an O/W type, while organic acids, halogens, etc. are solubilized and dissolved in water, and at the same time, they are dissolved in soil. It is extremely effective in providing sufficient wettability to the surface. On the other hand, the cobalt chloride complex compound, which is the mainstay of the present invention, can be uniformly dispersed in soil and cement while appropriately suppressing the cohesive force of particles. (separation phenomenon) is less likely to occur, and sichuntropy is promoted by I.lium chloride, contributing to maintaining the dispersion effect. In this way, the cement particles undergo a hydration reaction in a highly uniformly dispersed state, and the soil to be dispersed (including aggregates and other materials when used together) becomes islands, creating a so-called island-sea structure (Sea) in which the cement bait serves as a sea structure. -Islands
As a result, the gaps between the soil particles are filled with a uniform cement hydration paste, which functions as a binder (consolidating agent), thereby significantly improving the watertightness of the soil. In addition, colloidal silica contained in soil, aggregate, etc. and N, which is originally contained around 0.5% in cement.
Alkali silicate oligomer (low polycondensate) that places active sites in soil and 7-ment particles through the auxiliary reaction of the carbonate contained between A20 (oxidation sorter) and Ni20 (potassium oxide) and the catalytic action of the cobalt chloride complex compound. It is thought that, in parallel with the coagulation and hardening of the cement itself, the presence of sodium chloride causes a coagulation reaction and polycondensation to proceed, creating a network structure through covalent bonds and integrating with the cement hardening process materials. Both the cement and the alkali silicate oligomer are finally integrated in the island-sea structure. The present inventor is involved in the formation of this island-sea structure as well as cement! - It is estimated that the cobalt chloride complex compound makes a large contribution to the formation of inorganic oligomers in addition to the jlE normal curing reaction itself.

In addition, amines in organic substances are easily adsorbed especially as ligands of this complex compound, contributing to deodorization, and factors that interfere with adhesion with cement, such as oils and fats, are completely eliminated, and the wet state becomes uniform. The van der Waals force is the origin of the island structure in which the adsorption interface surrounded by complex compounds is in an extremely ionically active state, and the sea structure of cement hydrated Pace I is caused by ionic, electrical and other adsorption factors. While performing adsorption and adhesion, it hardens through condensation.

The present inventor has found that the solidified product obtained by the present invention maintains excellent strength and has appropriate elasticity, and that an impact applied to one point will not cause local fracture and develop into cracks like in general cement products. It has been confirmed that crack failure is less likely to occur because the impact force is diffused, and this is thought to be due to the completion of the reticulation and the formation of a web that acts as a spring throughout. It is inevitable.

According to the present invention, it is possible to produce solid hardened products as well as granular and granular products by selecting and combining the amount of cement and each chemical component depending on the purpose, and it goes without saying that the principle is to follow the above-mentioned process. .

To summarize the reasoning of the mechanism of the present invention as follows, (1) treatment of the soil with organic substances containing alkali carbonates and cobalt chloride complex compounds and surface activation associated with perfecting wettability;
(2) Uniform dispersion of soil and cement particles and dispersion retention due to sodium chloride, (3) Formation of island-sea structure and establishment of watertight system associated with it, (4) Formation of alkali silicate oligomers and heptament hydrate This means that the formation of a network polycondensate material is completed by curing upon coagulation and integration of the polycondensate.

Next, the present invention will be explained in more detail by showing examples.

Example 1 (Sample) Kanto loam ± (moisture 35.5%) (Processing) Kanto loam 2 (passed through 5m/+n sieve, 4 mesh) 100% Portland cement 20% Mixed liquid 2z (4 molten liquid formulation) Sodium chloride 8.5χ Potassium carbonate 6.0% Sodium carbonate 7.0% Ammonium chloride 1.5% Cobalt chloride 0.3% Water 78.7% Word 4 100% Mix the soil and cement well beforehand, then add the chemical solution. The stirred mixture was left in a metal molding machine with a diameter of 5 cm and a depth of 10 cm + n for 3 days, then molded, sealed in a polyethylene bag and cured at room temperature, and the strength over time (compressive strength) for 7 and 28 days was measured for 5 samples. The measured average values are shown below. Note that the compressive strength was measured using a CBR testing device based on JIS A1211.

(Sample) Red soil (moisture 40% or less) (Processing) Red soil 100X Portland cement 17% Mixed liquid 2.5z (Mixed liquid formulation) Sodium chloride 6. Oz potassium chloride 3. Oz Thorium carbonate '8.5% Potassium carbonate 5.8z Ammonium chloride 0.75% Cobalt chloride 0.15% Water 77.8% Total 100% The addition table was the same as in Example 1, and the test piece was 5 cm in diameter and 10 cm in depth. Cylindrical metal forming machine Shigawa was left to cure in the atmosphere for 3 days.

Maximum load 4,100kgf (compressive strength unit kgf/cn+2 ('N/mm2.)
)-91

Claims (1)

[Claims] l) A soil hardening treatment agent used in treating soil with cement, characterized in that 4% by weight or less of a cobalt chloride complex compound is present in an aqueous alkali metal salt solution, and the mixture is alkaline. .