KR20000049749A - A solidifying agent composition of which chief ingredient is low exothermic cement and a preparing method thereof - Google Patents

Abstract

PURPOSE: A low calorific cement-based solidifying agent composition is provided which intensively solidifies transported soil rich in an organic substance or poor ground soil having high moisture content. CONSTITUTION: A low calorific cement-based solidifying agent composition comprises 87.7 - 93.3 % of a three-component-system low calorific cement as a main material and a solidifying additive composed of 3.4 - 4.5 % of silica (SiO2), 0.9 - 2.2 % of expansion agent (CSA: Calcium Sulfur Aluminate), 0.6 - 1.4 % of bentonite, 0.6 - 1.4 % of anhydrous gypsum, 0.6 - 1.4 % of hydrated lime and 0.6 - 1.4 % of fly ash (F/A: pozzolan). The solidifying additive may optionally contain 0.3 - 0.7 % of stannic acid, and in this case, the content of the three-component-system low calorific cement will be 87 - 93 %.

Description

A solidifying agent composition of which chief ingredient is low exothermic cement and a preparing method etc.

The present invention relates to a solidifying agent for the solidification treatment of the soft ground, it is a high-strength used to strengthen the ground, such as soft ground, coastal wetlands and harbors difficult to solidify due to organic matter or high water content The present invention relates to a three-component low calorific cement solidifying agent having a short curing time.

In Korea, portland cement is usually used as a binder to solidify subbases or soft ground of roads. In special cases, blast furnace cement or crude steel cement was often used in place of portland cement. Cement does not immediately harden when it comes in contact with water and maintains its firing state for a certain period of time. This step is called setting, and the setting time in Korea's Korean Industrial Standard is based on 1 to 10 hours. The cement in the sintered state undergoes a hardening process in which the hydration is continued as time passes after the condensation is completed, thereby densely filling and solidifying the cement particles. This is because the constituents of cement come into contact with water, causing their respective chemical reactions to become different compounds. This is called hydration. On the other hand, it is known that cement alone cannot be effectively treated in soils containing large amounts of organic clays that can inhibit the hydration reaction of soft clay and cement having a high water content. This is caused by the disturbance of the hydration reaction by organic matter, the difficulty of solidification treatment with only cement in the case of soft clay or mud, and the occurrence of loosening site during long-term soaking due to the occurrence of dry shrinkage when using a large amount of cement. In order to solve this problem, cement is often used as a cement-based solidifying agent, in which Portland cement is mixed with additives according to the ground characteristics and construction purposes. Among the existing suspension-type and solution-type solidifying agents, the solidifying agents such as chromium green and acrylamide, which can cause pollution due to the pollution problem caused by chemical solidifying agents, have been banned in most countries since the late 1970s. It is becoming. Cement-based hardeners used in admixture with cement first generate a large amount of ettringite in the process of improving effect in the case of soft ground. Ethrinite absorbs a large amount of bound water, lowers the water content, and constrains the movement of the granules, making it easy to solidify. Then, the aggregated coagulation of the granules is aggravated by Ca ⁺⁺ ions eluted from calcium hydroxide, calcium citrate and the like, and the strength is increased by the production of calcium silicate hydrate. In addition, it is known that soluble components such as SiO ₂ and Al ₂ O ₃ contained in soil combine with Ca (OH) ₂ to produce insoluble hydrates, thereby making it harder with time.

In recent years, at home and abroad, the reclaimed works that fill up the ocean's seashores are used as basic grounds by safely treating marine or contaminated sedimentary cohesive soils for the construction of general landfill sites, the construction of artificial islands, the construction of new airports, ports, and the construction of water barrier walls for them. There is a growing number of cases that require ordering methods. However, these soft ground soils contain many organic substances due to long-term deposition or organic waste. As described above, organic matter is adsorbed on the surface of the granules, which not only prevents the mixed contact between cement and the solidified soil, As a result, it is difficult to solidify by inhibiting the direct reaction between cement hydrate and granules. As a result, the water content of the high water content such as coastal water is too high for cement, so that it is not possible to use forklift cement or steel cement or In the case of using blast furnace cement, solidification did not proceed smoothly and satisfactory high strength was not obtained. Although there have been many hardeners to compensate for the problems of general cements (Patent Publication No. 125466, Application Date December 21, 1993, Patent Publication No. 84-8557 Application Date December 29, 1984, etc.). As the main raw material is added in large quantities, there is a defect that curing is slow and heat is generated when solidification causes a change in volume, and cracks occur.In addition, efficient decomposition of organic substances or ents in the solidification component and ratio added to general cement Lingite was not produced, and there was a problem that the solidification was not good in the sedimentary soil or the ground having much moisture, which did not meet the standard even in the degree of hardening.

The present invention is to solve this problem, and to improve the strength without cracking for solidified soil containing organic matter, such as soft ground, coastal wetland, harbor and road composition, high moisture content or high clay content, and also heavy metals, etc. It is an object of the present invention to provide a soil hardener that solidifies contaminated soil containing pollutants to obtain a heavy metal leaching inhibition and ordering effect, thereby protecting the natural environment.

In order to achieve this purpose, the organic material is formed by blending (7 to 13%) solidifying additive components such as silica, expanding agent, bentite, anhydrous gypsum, calcined lime and fly ash with three-component low-heating cement as the main raw material (87 to 93%). It is characterized by solidifying strongly regardless of the target soil such as contained sediment, coastal soil with high water content, and viscous soil.

Unlike the conventional solidifying agent, the solidifying agent of the present invention uses a three-component low heat cement (Ssangyong Cement Co., Ltd.) as a main raw material, without using general cement. The reason is that in the case of general cement such as Portland cement, When the bonding reaction occurs, a rapid reaction is accompanied by the generation of heat of hydration, which causes a volume change, causing cracks due to volume expansion.However, defects occur as time elapses. As time goes by, strength increases (170 Kg / cm 2), and salt water has a merit that hardening occurs well.

In the present invention, three-component low-heating cement (SiO ₂₎ , which is a main raw material as shown in <Table 1>, to obtain an excellent solidification effect regardless of the target soil such as soil, clay, contaminated soil, or coastal soil with high water content, containing organic components. 38.0%, Al ₂ O ₃ 14.0%, Fe ₂ O ₃ 1.8%, CaO 37.6%, SO ₃ 2.0%, MgO 0.94%, others (heat loss such as equity) 5.66%) 87.7 ~ 93.3% (Silicon oxide: SiO ₂ ) 3.4-4.5%, swelling agent (CSA: Calsium Sulfer Aluminate) 0.9-2.2%, bentite 0.6-1.4%, anhydrous gypsum 0.6-1.4%, slaked lime 0.6-1.4%, fly ash (F / a; pozzolanic) combining an additive powder of the solidified component of 0.6~1.4% of the silica (silicon oxide; SiO ₂₎ 29.9~36.5%, aluminum oxide _{(Al 2 O 3) 7.67~9.37%} , iron oxide (Fe ₂ O ₃ ) 1.33 to 1.63%, calcium oxide (CaO) 45.27 to 55.33%, magnesium oxide (MgO) 3.36 to 4.10%, sulfur trioxide (SO ₃ ) 1.43 to 1.75%, others (heat loss, etc.) 1.06 to 1.30% Preparation of exothermic cement type solidifying agent composition The.

On the other hand, as shown in <Table 2>, 0.3-0.7% of tartaric acid is further added to the additive of the solidified component, and the ratio of the three-component low heat cement can be set to 87 to 93%.

The low calorific cement-based solidifying agent of the present invention is mixed with the powder as it is or with water at an appropriate ratio of about 1: 1, depending on the type of the soft ground soil, and the slurry is mixed to determine the mixing ratio according to the condition of the soil.

An example of the composition of the low calorific cement-based solidifying agent component of the present invention is shown in <Table 3>.

<Table 1> Mixing ratio (%) of the solidifying agent component of the present invention

3-component low heat cement Solidifying Agent Additives Silica Inflator Bentnight Anhydrous gypsum Slaked lime Fly ash 87.7 to 93.3 3.4 to 4.5 0.9 to 2.2 0.6 to 1.4 0.6 to 1.4 0.6 to 1.4 0.6 to 1.4 12.3 to 6.7

<Table 2> Mixing ratio (%) when tartaric acid is added to the solidifying agent component of the present invention

3-component low heat cement Solidifying Agent Additives Silica Inflator Bentnight Anhydrous gypsum Slaked lime Fly ash Tartaric acid 87-93 3.4 to 4.5 0.9 to 2.2 0.6 to 1.4 0.6 to 1.4 0.6 to 1.4 0.6 to 1.4 0.3-0.7 13-7

<Table 3> Composition ratio of the low calorific cement-based solidifying agent of the present invention

ingredient SiO ₂ Al ₂ O ₃ Fe ₂ O ₃ CaO MgO SO ₃ Others (heat loss, tartaric acid, etc.) Solidifying agent composition ratio of this invention 29.9 to 36.5 7.67-9.31 1.33-1.63 45.27 to 55.33 3.36-4.10 1.43-1.75 1.06-1.30

<Example 1>

After processing the chemical solution with 111L of water of 1 type Portland cement, 111kg of solidifying agent of the present invention, and 111kg of solidifying agent of the present invention, the sample soil having a high clay content of 1243kg / ㎥ and the water content of 60.56% Test of uniaxial compressive strength by making a mold.

Comparative Test 1

Circumstance 7 days 14 days 28 days 365 days Compressive strengthKg / ㎠ Class 1 Portland Cement 0.43 0.67 0.96 1.24 Conventional solidifying agent 0.86 1.54 2.13 2.77 Solidifying Agent Of The Invention 1.32 1.89 2.56 3.27

<Example 2>

The sample soil of 1387 kg / m3 of soil with a large volume of waste and 51.6% of water content was mixed with 97 L of water in one kind of Portland cement, 97 kg of conventional solidifying agent and solidifying agent of the present invention. Uniaxial compressive strength comparison test.

Comparative Test 2

Circumstance 7 days 14 days 28 days 365 days Compressive strengthKg / ㎠ Class 1 Portland Cement 1.64 2.14 2.87 3.31 Conventional solidifying agent 2.73 4.10 5.27 7.04 Solidifying Agent Of The Invention 4.21 6.57 8.34 12.27

<Example 3>

Organic soil-rich soft soil unit volume weight 1355kg / ㎥, water content 55.3%, 1 portland cement, 121kg of solidifying agent and conventional solidifying agent of the present invention mixed with 121ℓ of water, and then injected into the sample soil and stirred to make a mold. Compressive strength comparison test.

Comparative Test 3

Circumstance 7 days 14 days 28 days 365 days Compressive strengthKg / ㎠ Class 1 Portland Cement 0.86 1.24 2.33 2.96 Conventional solidifying agent 1.23 2.34 3.98 5.08 Solidifying Agent Of The Invention 2.66 3.87 5.43 7.27

<Example 4>

Soft soil with high water content 1376kg / m3, water content 71.7% mixed with 1 type Portland cement, conventional solidifying agent and 124kg of solidifying agent of the present invention after mixing 124ℓ of water, injecting into sample soil, stirring and making mold Compressive strength comparison test.

Comparative Test 4

Circumstance 7 days 14 days 28 days 365 days Compressive strength Class 1 Portland Cement 0.86 0.96 1.35 1.93 Conventional solid fire 0.96 1.78 3.34 5.27 Our Fire 2.76 3.48 5.04 7.63

The method of carrying out the solidifying agent of the present invention on soft ground soil is as follows.

First, take samples from the construction site and conduct soil analysis such as moisture content, wet density, harmful substance content, thermal loss, soil component, specific gravity, and particle size analysis. With the mixing ratio of powder 87-93: 13-7 (or 87.7-93.3: 12.3-6.7), after preparation of specimens by each addition amount, compression strength measurement, permeability coefficient, dissolution test, The amount of the solidification additive added is determined and a solidifying agent is added according to the target soil.

Depending on the construction conditions, a slurry-based solidifying agent or powder solidifying agent may be used, but when sprayed in a stirrer, the solidifying agent may be mixed with water in a 1: 1 ratio.

Low calorific cement-based solidifying agent of the present invention, as can be seen in the comparative test of each of the above examples of the decomposed clay was weak compared to the conventional portant cement or a solidifying agent prepared by formulating a certain solidified component based on the same; It is excellent in the application of soil containing organic matter, soil containing soil and high water content so that it can be used without restriction of target soil and it can be used not only in soft ground but also in heavy metal contaminated ground, so it can prevent the leakage of heavy metals. Pollution can be prevented in advance, and low heat cement is used to improve the strength over a long period of time, so that stability is high without cracking, and various compounding designs are possible according to the required strength, and the hardening time is short. Advantageous to retaining walls, soft soils, sewer pipes, housing construction and structures It has excellent performance in basic ground improvement, in situ solidification such as fill, sludge and hedor, and soil stability treatment of soft ground.

Claims (3)

In soft ground solidifying agent, 87.7 ~ 93.3% of three-component low heat cement, 3.4 ~ 4.5% of silica (silicon oxide), 0.9 ~ 2.2% of swelling agent (CSA: Calsium Sulfer Aluminate), 0.6 ~ 1.4% of bentite, 0.6 gypsum 0.6 A method for producing a low calorific cement-based solidifying agent composition, comprising:-1.4%, slaked lime 0.6-1.4%, fly ash (F / A: pozzolane) 0.6-1.4% of an additive powder of a solidifying component. In soft ground hardener, three-component low-heating cement 87-93%, silica (silicon oxide) 3.4-4.5%, swelling agent (CSA: Calsium Sulfer Aluminate) 0.9-2.2%, bentite 0.6-1.4%, anhydrous gypsum 0.6 Low calorific cement system characterized in that it is composed of the additive powder of the solidified component of -1.4%, slaked lime 0.6-1.4%, fly ash (F / A: pozzolane) 0.6-1.4%, tartaric acid 0.3-0.7% Topical composition preparation method. In soft ground hardener, silica (silicon oxide; SiO ₂ ) 29.9 to 36.5%, aluminum oxide (Al ₂ O ₃ ) 7.67 to 9.37%, iron oxide (Fe ₂ O ₃ ) 1.33 to 1.63%, calcium oxide (CaO) A low calorific cement-based solidifying agent composition comprising 45.27 to 55.33%, magnesium oxide (MgO) 3.36 to 4.10%, sulfur trioxide (SO ₃ ) 1.43 to 1.75%, and other 1.06 to 1.30%.