KR20030093632A - Mixed cement, mortar or concrete, and manufacturing method thereof - Google Patents

Abstract

PURPOSE: An environmentally friendly mixed cement having no stimulative odor and toxicity is provided to improve the human living environments. A cured cement product having a low pH obtained from the mixed cement is also provided. CONSTITUTION: The environmentally friendly mixed cement comprises 90-50 wt% of portland cement powder and 10-50 wt% of illite powder. The mixed cement further comprises 0.01-1.5 parts by weight of an organic polybasic acid selected from the group consisting of citric acid, tartaric acid and a mixture thereof, based on 100 parts by weight of the total amount of the cement and illite powder. The mixed cement optionally further comprises 10-40 wt% of a material selected from a fly ash, a terra alba, a slag and a volcano ash based on the total amount of the cement and illite powder.

Description

Environment-friendly mixed cement, hardened cement produced therefrom, and method for manufacturing the same {Mixed cement, mortar or concrete, and manufacturing method

The mixed cement of the present invention converts Ca (OH) ₂ and Na ₂ O, K ₂ O, which are strongly alkaline toxic substances contained in the hardened cement of Portland, into non-toxic polybasic acid salts by neutralizing citric acid or tartaric acid and clay minerals. Due to the action of forming a non-toxic cement hardening body, that is, crystals such as CSH and CAH, by the pozzoran reaction between the yrite and Ca (OH) ₂ , Ca (OH) ₂ , Na ₂ O, K ₂ O, etc. It is an environmentally friendly mixed cement that greatly reduces strong alkaline toxic substances.

Among the Portland cement contains approximately 65% of the CaO, and the cement is hydrated when CaO is ionized, separated by Ca ²⁺ and O ^2- of Ca ²⁺ ions dissolved in the ionized water is hydrated initial OH ^- ion reacts with the Ca (OH) ₂ , ie, slaked lime. The composition of Portland cement clinker components is C ₃ S 45-52%, C ₂ S 24-29%, C ₃ A 8-11%, C ₄ AF 8-10%, etc. Among them, C ₃ S and C ₂ S generates a large amount of Ca (OH) ₂ by the sign language as follows.

2C ₃ S + 6H ₂ O = C ₃ S ₂ H ₃ + Ca (OH) ₂

2C ₂ S + 4H ₂ O = C ₃ S ₂ H ₃ + Ca (OH) ₂

Ca (OH) _{2, which} is soluble in water produced in large quantities by this hydration, reacts with gypsum at the beginning of hydration to form ettring guides (C ₃ A · 3CaSO ₄ · 32H ₂ O). It is reacted and consumed to form various CSH and CAH cement gels, and the remaining Ca (OH) ₂ is present in the glass state in numerous capillary holes formed in the cement hardened body, which is 20% of the amount of cement. It is me.

The light used in the present invention includes silica and alumina as main components, and the amount of amorphous silica and alumina capable of causing pozzoran reaction is about 25 to 35%. This light powder also hardly participates in the composition of cement hardeners such as various CSH gels and CAH gels in the cement hydration process, and is pushed into capillary balls during the coagulation hardening step to be in position with free Ca (OH) _2. Na alumina reacts with free Ca (OH) ₂ for a long period of time to produce CSH and CAH crystals, which are hardly soluble cement hardeners. Watertightness improves, resulting in increased long-term strength.

On the other hand, the role of citric acid or tartaric acid, which is an organic polybasic acid having an OH group used in the present invention, not only delays the hydration curing effect of cement, but also Ca (OH) ₂ , a toxic strong alkali component present in the capillary pores of cement. Neutralization reaction with Na ₂ O, K ₂ O and the like forms various citrate or tartrate which is non-toxic and close to neutral pH, which not only lowers the pH of the cured product but also eliminates whitening phenomenon. The presence and extent of efflorescence is a measure of the effectiveness of the present invention. The reason for the whitening depends on the nature of the material such as the place of occurrence, timing, cement, aggregate, and water, but generally CaCO ₃ , Na ₂ SO ₄ , K ₂ SO ₄ , Na ₂ CO _3, and the like.

Portland cement has about 20% of Ca (OH) ₂ by hydration and contains about 0.5-10% of Na ₂ O, K ₂ O, Na ₂ SO ₄ , K ₂ SO _4, etc. All of which have significant solubility. These solubles are dissolved in the water in the capillary pores between the cement gel and the gel, but migrate to the surface as the evaporation of the water, all of which are strongly alkaline, reacting with CO _{2 in the} air, CaCO ₃ , Na ₂ CO ₃ , K ₂ CO Precipitate carbonates, such as _three . Among these, CaCO ₃ is precipitated by the reaction of Ca (OH) ₂ and CO ₂ , and unlike Na ₂ CO ₃ and K ₂ CO ₃ , it is poorly soluble in water and can not be erased even by wiping with water.

As described above, the cement cured body of the present invention has almost no whitening phenomenon due to the formation of various citrate salts, tartarate salts, etc., which are close to neutrality by neutralization of citric acid, tartaric acid, and the like by the pozzolan reaction by elight.

The present invention relates to a kind of mixed cement used in the production of mortar or concrete, and a cement hardened body prepared therefrom, and more particularly, by mixing a certain amount of ilite powder and a certain amount of citric acid or tartaric acid powder in Portland cement. It relates to an environmentally friendly mixed cement obtained and a cement hardened body produced therefrom.

As those described in KS as mixed portland cement, there are slag cement, silica silica, and frying ash cement, and these mixed cements will be briefly described as follows.

(Mixed cement)

Currently, various mixed cements developed using Portland cement as a base material and raw materials do not have curability alone, but when water coexists, they cause a reaction with Portland cement and pozzolan to form a gel such as CSH or CAH or to hydrate the cement. It is a cement mixed with Portland cement, a material that stimulates and expresses condensation hardening, and all of them are based on Portland cement.

Typical examples include slag (blast furnace) cement, silica cement, and frying ash cement. These are cement blended with portland cement, blast furnace slag, volcanic ash, and frying ash. There is economy. The cement will be described in more detail below.

(1) Portland blast-furnace Slag cement

Slag cement is a crushed cement mixture of blast furnace slag and Portland cement clinker, and is classified into three types according to the amount of slag. The slag content is 5-30% for class A, 30-60% for class B and 60-70% for class C.

The blast furnace slag itself does not have the property of curing by reacting with water, but when contacted with Portland cement, it is stimulated to develop hydraulic properties, that is, it exhibits latent hydraulic properties.

Slag cement is characterized by low heat of hydration and high chemical resistance. The slag obtained from the steel mill is composed of SiO _2, Al ₂ O ₃ , and CaO ₃ , and its composition is generally 33 to 35% SiO ₂ , 14 to 18% Al ₂ O ₃ , and 0.5 to ₃ Fe ₃ O ₃ . 2%, CaO 38-45%, MgO 4-8% range, the composition is less CaO and more SiO ₂ compared to Portland cement. In pH, slag cement is about 12.70, and slag is about 10.47.

The properties of slag cement have the advantage that the flow value is relatively large and the workability is good and the W / C ratio may be reduced. The slag cement strength up to 28 days of concrete is weaker than that of Portland cement as the slag content is higher, but A, B, and C types are stronger than Portland cement after 6 months of age. A big feature of slag cement is its high chemical resistance compared to other cements. In case of Portland cement, a large amount of hydrated lime [Ca (OH) ₂ ] is produced by the hydration reaction of C ₃ S and C ₂ S, which causes sulphate solution and ettring guide to expand and destroy, but in case of slag cement The less the amount of Portland cement is mixed, the less the slaked lime is, and the resulting slaked lime reacts with the slag to form an insoluble CSH gel and stabilize. This property is closely related to the present invention.

In general, the higher the SiO ₂ content and the lower the CaO content in the cement, the higher the acid resistance tends to be. Hydration heat of medium Portland cement can be maintained at the same level as medium Portland cement by mixing 64.2㎈ / g on the 7th day and 80.4㎈ / g on the 28th or more than 40% of the slag. Widely used in the field of mass concrete.

(2) Shirika cement

Silica cement is a cement obtained by mixing a siliceous admixture with a Portland cement clinker, and is called silica silica due to its high SiO ₂ content. Depending on the amount of siliceous mixture, it is divided into three types A, B, and C. It is classified as 5 ~ 10% A, 10 ~ 20% B, 20 ~ 30% C, and mixed and pulverized with Portland cement clinker and gypsum. Commercialize. As the homogenous mixture, pozzolan (volcanic ash) or acidic clay is mainly used, and these are all composed of amorphous silica and have no curing property with water, but 20 to 40% of SiO _{2 which is} soluble to 10% NaOH and 5% HCl, such as It contains 2 to 5% of Al ₂ O ₃ .

These soluble components gradually react with free lime-calcined Ca (OH) ₂ during cement hydration to produce CSH gels or CAH gels that are poorly soluble in water, thereby making a so-called pozzolan reaction. The Pozoran reaction improves the properties of Portland cement and increases its water resistance, chemical resistance and long-term strength. Such properties of silica silica are closely related to the present invention.

(3) fry ash cement

Fry Ash Cement is a cement blended with Fry Ash in Portland Cement. Fry Ash is a dust collector that collects pulverized coal ash in the combustion gas of pulverized coal-fired coal-fired power plant. It is amorphous and its composition varies depending on the type of coal, but more than 45% of SiO ₂ powder and more than 2400㎡ / g is used for cement. In addition, since the particles are almost spherical, the fluidity of the cement paste is increased due to the sliding action of the particles, so-called bearing action, thereby lowering the W / C ratio. The commercially available fried ash has a pH of about 10.35, which is considered to have a significant Ca component.

Fry ash is not curable alone, but contains a lot of soluble amorphous SiO ₂ such as pozzolan or clay, so that the reaction of calcined lime and pozzolan liberated from C ₃ S and C ₂ S causes insoluble CSH gel (gel ) Is closely related to the present invention. The short-term strength up to 28 days is low, but the long-term strength over 6 months is the same as that of ordinary Portland cement, and the structure of hardened body is dense, so it has high waterproofness, chemical resistance and low heat of hydration, which is suitable for mass concrete construction.

(4) other cement

In general, cement based on Portland cement, such as crude steel or crude steel Portland cement, medium heat Portland cement, sulfuric acid Portland cement, etc., are all included in the category of Portland cement used as the base of the present invention.

Portland cement using organic acids having OH groups in the molecule, such as tartaric acid, citric acid, saccharic acid, tetrahydroxy-adipic acid and Na or Ca salts of these acids, in addition to the mixed cements described above There is a patent that has modified the properties of. Specifically, in US Pat. No. 2,174,051, when an organic acid as described above is added to Portland cement to form an cement hardened body such as mortar or concrete, the flowability of cement powder and paste can be improved, and the water and cement ratio can be reduced, and condensation ( setting) proceeds slowly, but hardening proceeds rapidly to increase strength.

U.S. Patent No. 2,543,364 also discloses Ca-salts of tetrahydroxy adipic acid at 0.125% by weight of cement, lauryl alcohol sulfate, sodium resinate, Al-powder and air of Vinsol resin. It is disclosed that adding cementing agent to cement to make cement hardened material such as mortar or concrete can make cement hardened material of frost resistance structure.

In addition, US Pat. No. 3,656,985 adds 0.5-5% of an alkali metal-aluminate (Na-aluminate) to the cement to quickly cement the cement, so that the cement paste is quickly formed. The use of tartaric acid, citric acid, sugar acid, maritic acid, lactic acid, salicylic acid and salts of these acids as a modifier that can accelerate the condensation while preventing condensation is disclosed in the range of 0.05 to 2% of the weight of cement.

The difference between the above description and the present invention is described as follows.

In the present invention, the purpose of using citric acid or tartaric acid is an environmentally friendly acid that is relatively environmentally acidic without dissolving amorphous silica or alumina that is present in the light powder, fried ash powder, slag powder, and the like, and reacts with pozzorans. It is to use the function that can significantly lower the pH, and is never used for the purpose disclosed in the above-mentioned US patent.

The present invention uses a relatively ferric acid citric acid or tartaric acid as 0.01 to 1.5% by weight of the cement to neutralize the strong alkali component in the cement paste to form the organic acid salt of neutral or weak alkaline, and 10 A pH of 10.0 is generally maintained while maintaining the strength of the cement hardened body by producing a cement hardened body such as CSH and CAH, which is weakly alkaline, by a pozoran reaction between the light containing ~ 50% and Ca (OH) ₂ in the hardened cement. The contents of US Patent No. 2,174,051, as described above, refer to not only too many kinds of organic acids, but also alkaline salts of these acids, and weakly alkaline Na-aluminates. In view of lowering the pH of the cement hardened body due to the use of a hydride oxidizing agent, There is a fundamental difference from the content.

The contents of U.S. Patent No. 2,542,364 refer to the use of Ca-salts of tetrahydroxy adipic acid with 0.125% of the weight of cement with near neutral pH to obtain a hardened frost resistant cement hardener. Too far from the invention.

U.S. Patent No. 3,650,985 discloses that the cement paste of the present invention proceeds rapidly within the range where the cement paste is not quenched by mixing 0.5-5% by weight of Na-aluminate with 0.005-2% of various organic acids and salts thereof. Belongs to the distant invention.

On the other hand, Korean Patent Application No. 1997-65471 discloses a technique related to mortar prepared by mixing 40 to 45% of the light powder in the proportion of sand 30 to 35%, white cement 20 to 30%, citric acid, tartaric acid There is a significant difference from the present invention in which the action and the action of the light are linked to obtain a low pH environmentally friendly cement and mortar or hardened concrete.

In addition, Korean Patent Application No. 2001-29197 discloses a ceramic artificial reef, a ceramic band made of at least one of germanium, loess, and light as a raw material of a ceramic member on a reef body made of concrete or iron, and an iron band. It relates to the production of fishes made by attaching to the four sides of the body using. Here, it is said that at least one of germanium, ocher, and irite is selected as a raw material of the ceramic member. Here, in addition to the irite, it is used for the ocher and germanium instead of cement. It is too far from the present invention to reduce or eliminate Ca (OH) ₂ , which is a toxic component, by the pozzoran reaction of yrite.

Pozolan reaction

This reaction is clayey minerals and the like as the material containing a large amount of such as amorphous silica or alumina, but does not have the property of curing with water and itself cement hydration when Ca (OH), such as ash, acid clay, for siliceous honhapjae Example ₂ And gradually combine to form poorly soluble CSH gels or CAH gels to further densify the hardened tissue. This reaction is called Pozoran reaction, and amorphous silica or aluminum oxide is dissolved in 5% hydrochloric acid or 10% caustic soda.

(Hazards of Portland Cement)

A typical Portland cement powder contains about 64% of CaO, and when the cement is hydrated, CaO is separated and ionized into Ca ²⁺ and O ^2- and the dissolved ionized Ca ²⁺ reacts with the OH ^- ion in water at the beginning of hydration. To form Ca (OH) _2, that is, lime.

According to the literature, Ca (OH) ₂ is irritating to the skin and causes various skin diseases. Therefore, the amount of Ca (OH) ₂ should not be inhaled over a certain amount.TLV (Threshold Limit Value) is defined as 5mg / m ³ in the air. have. The TLV is designed by the United States Government's Institute of Occupational Hematologists for the health of people working in the same environment and conditions every day. In other words, the value of the TLV 5mg / m ³ means that the continuous operation in the space where the lime powder of 5mg or more in the 1m ³ space is dangerous to health.

TLV as described above also applies to cement powder. The reason for this is that assuming that workers in cement processors inhale cement powder through continuous breathing, about 64% of CaO contained in the cement acts as moisture in the body, causing Ca ²⁺ It is reported that the Ca ²⁺ ions will be ionized to form Ca (OH) ₂ and the extra Ca ²⁺ ions enter the blood to coagulate and cause diseases such as angina pectoris and hypertension.

Calcium plays an important role in hard tissues such as bone, blood, and cytoplasm in our human body, but when ingested in excess, it is harmful as described above. The foods we eat, such as milk and cheese, are high in calcium, and the fact that Westerners who consume these foods every day are more likely to suffer from atherosclerosis or hypertension than in Asians who eat less. It is considered that serious consideration should be given to the problem of health disorders.

The industries that dominate the 21st century are often said to be environmental and telecommunications. It is an era where environment is important in every field.

Currently, the city lives in the forests of concrete or mortar made of ordinary Portland cement, and people living in new apartments have suffered or suffered skin diseases due to the cement's irritability and toxicity.

This is not only a problem for humans, but in the case of marine plants, they are manufactured using ordinary Portland cement, which does not grow plants due to the toxicity of cement for at least three years. Not all fish are approached.

The reason for the lack of access to fish is that Ca (OH) ₂ , which is highly irritating, toxic, and has a pH of about 11.45, is contained in capillary pores of about 20% by weight, which is traced to salt water over three years. It is considered to be because it is dissolved and leaked.

Accordingly, the present invention is to provide a method for making environmentally friendly cement hardening material, that is, various buildings, various concrete and mortar structure products, as a result of adding citric acid or tartaric acid and light to portland cement, usually mortar or concrete The present invention was found to be significantly reduced or eliminated by the action of citric acid, tartaric acid and yrite, in which toxic slaked lime and other strong alilic components contained in the capillary pores of the cured body in an amount corresponding to about 20% of the weight of cement were completed. .

Accordingly, it is an object of the present invention to provide a mixed cement that can reduce or eliminate the amount of slaked lime and other alkali components contained in capillary or gel pores of a general mortar or concrete cured body to make an environmentally friendly cement cured body. .

It is also an object of the present invention to provide a cement hardened body prepared from such mixed cement.

And this invention also has the objective in providing the method of manufacturing such hardened cement.

In addition, an object of the present invention is to make a variety of environmentally friendly buildings, various concrete and mortar structure products to greatly reduce the hazards caused by cement to greatly improve our residential environment.

Mixed cement of the present invention for achieving the above objects is from 90 to 50% by weight of Portland cement powder, 10 to 50% by weight of light powder, and 0.01 to 1.5 with respect to 100 parts by weight of the total amount of cement powder and light powder It is characterized by containing citric acid or tartaric acid corresponding to parts by weight.

The environmentally friendly cement hardened body of the present invention is prepared from the mixed cement as described above, and the method for producing the same is added to the cement powder and 90-50% by weight of the light powder 10-50% by weight of the cement powder and Adding a citric acid or tartaric acid powder corresponding to 0.01 to 1.5 parts by weight based on 100 parts by weight of the total amount of the light powder, followed by stirring at room temperature to produce a mixed cement in which the cement and the light are uniformly mixed; Adding a small aggregate or coarse aggregate to the electrical process and adding water corresponding to a water-cement ratio of 30 to 60% to produce a mixed cement paste; Steam curing the electrical paste; And optionally further performing a step selected from natural curing, curing with water, and continuous washing in the air.

In addition, 10 to 50% by weight of the lightrite powder is added to 90 to 50% by weight of Portland cement powder and stirred at room temperature to prepare a mixed cement in which cement and light are uniformly mixed; Citric acid or citric acid or tartaric acid corresponding to 0.01 to 1.5 parts by weight based on 100 parts by weight of the total amount of the cement powder and the light powder in the electric process and citric acid dissolved in water having a water and cement ratio of 30 to 60% Adding a tartaric acid aqueous solution and a small aggregate or a coarse aggregate to prepare a mixed cement paste; Steam curing the electrical paste; And optionally through the step of additionally performing a step selected from natural curing, curing with water and continuous washing in the air can be produced an environmentally friendly cement cured body of the present invention.

The present invention will be described in more detail as follows.

To in-depth analysis of the technical problem to be achieved by the present invention, first, the process-specific aspects in the process of hydration, condensation, and curing of Portland cement, which are the main raw materials, should be carefully examined. In this regard, the technical problems must be closely reviewed in advance as well, such as drying shrinkage and bleaching.

Portland cement (hereinafter referred to as cement) reacts with water to produce hydrates to condense and harden. Therefore, hydration and hardening are closely related. Hydration of cement is mainly composed of hydration of so-called cement compounds present in cement, but the hydration mechanism and speed thereof are still unclear.

(Hydration, Condensation and Curing of Compounds in Portland Cement)

Cement compounds C ₃ S, C ₂ S, C ₃ A and C ₄ AF are highly reactive anhydrides and react with water to produce safe hydrates with low solubility. There are many theories about the ability of cement compounds to coagulate and harden with water.

(1) Hydration and condensation of cement

The hydraulic property of cement is the most basic characteristic, and it is the greatest feature of cement that it exhibits high strength and durability which are generated by mixing, stirring and curing with water.

Cement paste has fluidity during freshness and gives time for transport and construction, but becomes more viscous as it becomes hydrated and set to a setting state, which enters the hardening stage and gives strength over several decades. Promote.

(2) Portland Cement Clinker

Commercially available cement powder is composed of a mixture of clinker and gypsum powder corresponding to 3 to 5% of the weight of the clinker.

When the polished surface of the clinker is observed under an optical microscope, four phases are observed. The most developed columnar or hexagonal plates are alite (CS ₃ ), ships in circular form (belite, C ₂ S), insulators that fill the gap between the erite and the bilite (insterstitial material) ), The dark part is Ca-aluminate phase, the bright part is Ca-ferrite phase, and the elite, bilite, and aluminate phases are all solid solutions and are composed of many components. Main components are 3CaO · OO ₂ (C ₃ S), β-2CaO · SiO ₂ , 3CaO · Al ₂ O ₃ (C ₃ A), and the main component of ferrite phase is 2CaOFe ₂ O ₃ -6CaO · 2Al ₂ O ₃ It belongs to a part of Fe ₂ O (C ₂ FC ₆ A ₂ F) -based interface.

On the other hand, their composition is known as C ₃ S 45-52%, C ₂ S 24-29%, C ₃ A 8-11%, C ₄ AF 8-10% and the like.

(3) cement-water reaction

The hydration reaction of Portland cement is carried out by the hydration reactions of the various clinker minerals mentioned above, and in particular, a complex heterogeneous chemical reaction occurs in contact with a solution such as gypsum, alkali, and calcium hydroxide, which is dissolved in water in a unique state. In addition to the influence of / C and the temperature during hydration, physical conditions such as the specific surface area of the product, the porosity of the hardened body, and the size and shape of the cement particles cannot be ignored. There are still many differences between scholars.

Based on a recent announcement by N.R.Grellning, D.L.Kantro et al.

When water comes into contact with the cement, hydrolysis occurs immediately so that the liquid phase is supersaturated with Ca (OH) ₂ and SiO ₂ and saturated by gypsum. Some of the alkali is also extracted but reacts with CaSO ₄ solution to form Ca (OH) ₂ , so the reaction remains constant, but alkali generally contains more K ₂ O than Na ₂ O. Aluminate and ferrite produce C ₂ AH ₈ , C _s AH _19, C ₄ (A, F) H _13, C ₃ AH ₆ , and Fe ₂ O ₃ hydrate, but with sufficient Ca (OH) _{2 in the} liquid The presence of CaSO ₄ leads to precipitation of the etring guide within a few minutes, which reduces the concentration of SO ₃ ions, resulting in a low sulfate type C ₄ ASH ₁₂ -rich gel. In the meantime, as the CS ₃ is hydrated, the concentration of Ca (OH) ₂ is increased to crystallize to form a nucleus. At the same time, the nucleation of a stable CSH gel begins, and the unstable gel dissolves in the film on the surface of the CS ₃ and precipitates on the nucleus. When the surface of CS ₃ is cleaned, the hydration reaction is activated to increase the supersaturation state of Ca ²⁺ ions. In this way, when the CS ₃ surface is surrounded by a stable gel again, the hydration rate is inactivated again, but the hydration rate is gradually increased, and a stable CSH gel is formed on the protrusion of each particle to precipitate on the Ca (OH) ₂ surface. The particles are grown to form a thin network structure, and hardened through a condensation process to enhance strength.

(4) Cement Hydration Scheme

The hydration of the cement is complex as described above, and it is not easy to express it by a simple chemical equation.

2C ₃ S + 6H ₂ O = C ₃ S ₂ H ₃ + 2Ca (OH) ₂

2C ₂ S + 4H ₂ O = C ₃ S ₂ H ₃ + Ca (OH) ₂

2C ₃ A + 21H ₂ O = C ₂ AH ₆ + C ₄ AH ₁₃

2C ₂ AH ₈ = C ₃ AH ₆ + CAH ₁₀

C ₄ AF + (8 + n) H ₂ O = C ₂ AH ₈ + C ₂ FHn

CaSO ₄ ㆍ 0.5H ₂ O + 1.5H ₂ O = CaSO ₄ + 2H ₂ O

C ₃ A · mH ₂ O + 3CaSO ₄ + nH ₂ O = C ₃ A · 3CaSO ₄ ㆍ H _30-32

(5) Cement hardening and strength development

There is no single layer between the solidification and hardening of the cement, but it is practically required to set a compartment physically, and the start and end of the solidification is to measure the penetration of the cement paste by measuring the firing of the cement paste. In general, the starting time of condensation at room temperature of Portland cement is 2 to 3 hours, and the end is 3 hours 30 minutes to 5 hours.

Cement paste has CSH thin needles protruding from unhydrated particles at about 2 hours after coma, which makes a broad lath, which grows to form a network structure that intersects the entire paste. It is in the form of a sheet, sometimes wrapped around Ca (OH) ₂ . The hydrate of aluminate and ferrite produced immediately after the coma is combined with SO ₃ ions to form an ethring guide, and when gypsum is consumed completely for 5 to 24 hours, it is changed to aluminate and ferrite low sulfate type aluminate. Same as one.

(Shrinkage of Cement Hardened Body)

In the air, even if the humidity is high, shrinkage proceeds by evaporation of moisture from the cured product. The presence of water in the hydrate, voids, and voids in the cement hardened body changes with vapor pressure. Moisture evaporated under standard drying conditions is divided into free water: adhering water, adsorbed water, capillary water and semi-fixed water: gel water, and gel adsorbed water between gel layers. Moisture that does not evaporate is structural water that is firmly bound to hydrates.

The dry shrinkage shrinks by evaporating water in a large capillary tube in the cured body when the relative humidity decreases. After the initial drying, a hysteresis curve is developed that expands when wet and shrinks when dried, regardless of porosity, but the shrinkage due to evaporation of residual water becomes gentle after several months, but not more than thirty years later.

(1) carbonation shrinkage

Hydroxide lime glass in the cured product [Ca (OH) ₂ also known as a calcium hydroxide] is mainly present in the capillary hole, and this causes a shrinkage by changing the crystal structure and the capillary structure is in CaCO ₃ reacted with CO ₂ in the atmosphere. In addition, this reaction may cause poorly soluble whitening on the surface of the cured product. The rate of carbonation is determined by the moisture content in the paste and the humidity outside, resulting in maximum shrinkage at 50% to 60% relative humidity.

External factors governing shrinkage include atmospheric humidity, temperature, wind speed, and CO ₂ concentration.Inner factors include mineral composition of cement, W / C ratio of paste, and the size and distribution of capillaries. In the cement mineral, C ₃ A and C ₃ S are shrinkage components, CaO and MgO of gypsum and glass are expansion components and C ₂ S and C ₃ AF are components with low shrinkage.

In the cement of the present invention, carbonation shrinkage hardly occurs by greatly reducing the amount of Ca (OH) ₂ present in the free state in the cured body.

On the other hand, in case of accelerated curing such as steam curing and high pressure steam curing, the subsequent shrinkage is markedly reduced because the expansion and contraction are completed during the accelerated curing.

(Frash setting and false setting)

As described above, most of the hydration processes go through a normal condensation process, but sometimes an abnormal condensation occurs.

Quick quenching is a phenomenon in which the reaction is ideally fast after coma, causing water to evaporate from the surface due to rapid exotherm and to solidify in water, and rarely occur in mixed cements containing asbestos-free cement, gypsum-deficient cement, and admixture containing high soluble alumina. Such quickening foam cannot be used in various constructions, and if it is kneaded with water again, it is dangerous because of its low strength and cracks.

The cement of the present invention uses citric acid or tartaric acid to significantly delay the condensation rate, so that the quenching phenomenon can never be seen.

False condensation is a phenomenon of light solidification at the initial stage of hydration, which is caused by dehydration or weathering of the plaster when the cement is ground. Gypsum is dehydrated at 100 ~ 150 ℃ to become semihydrate gypsum (CaSO ₄ · 1 / 2H ₂ O), and then to gypsum at high temperature. They react with water very quickly to form dihydrate gypsum (CaSO ₄ ㆍ 2H ₂ O), but this rate is higher than the elution of C ₃ A, causing gas condensation. In weathering cement, alkali in cement absorbs CO ₂ in air and becomes carbonate, which acts with Ca (OH) ₂ or CaSO ₄ 2H ₂ O by coma to precipitate CaCO ₃ in colloidal form and Ca ²⁺ ion in solution. To reduce condensation and promote condensation, resulting in gas condensation. Cement, which shows false condensation, can be used for concrete.

On the other hand, the mixed cement according to the present invention is made by adding a light powder and citric acid and tartaric acid powder alone or a mixed powder of these acids to Portland cement powder.

Specific properties of citric acid or tartaric acid and light are as follows.

Citric acid is an organic acid widely distributed in plants and animals, and its formula is represented by HOOCCH ₂ -C (OH) COOH-CH ₂ COOH. This acid is colorless, translucent crystals or powder, has strong acid taste, specific gravity of 1.542 and extremely soluble in water.

In the distribution of animals and plants, especially, the fruit contains about 4.0 ~ 8.0% in lemon, about 1.2 ~ 2.1% in grapes, and about 0.6 ~ 1.0% in orange. It is contained in the entire human body contains about 1mg / ㎏.

Besides, 0.1 ~ 0.25% is used in various drinks, 0.25 ~ 4.0% is used in taste and flavor control agents. It is also widely used in jerry, soap, candy, cosmetics, etc. According to the literature, it has a dispersant, antioxidant, and antimicrobial effect. It is extremely environmentally friendly material.

Citric acid is described in the literature as having the following functions when used in cement mortar or concrete; ① Delays hydration condensation of mortar, concrete, plaster plaster, etc.

② By improving the dispersibility and fluidity of the cement paste, the workability is improved and the water-reducing effect is exhibited.

③ Increase the early sensitivity when used with air entrainer.

④ Because it does not corrode metal surfaces such as iron and has cleanliness and glossiness, it does not corrode the reinforcing bars of the concrete layer. It can prevent the damage caused by lubricating oil.

Citric acid forms citrate, such as calcium, potassium, sodium, etc. The citrate expected to be used in cement is described in detail in Table 1 below.

① calcium citrate salt Ca ₃ (C ₆ H ₅ O ₇ ) ₂ ㆍ 4H ₂ O White needle crystal ⇒ Difficult to water ② Gallium Citrate K ₃ C ₆ H ₅ O ₇ ㆍ H ₂ O White fine powder ⇒ soluble in water ③ sodium citrate Na ₃ C ₆ H ₅ O ₇ ㆍ 2H ₂ O White crystals ⇒ soluble in water ④ Ferric citrate Fe ₂ C ₆ H ₄ O ₇ ㆍ FeC ₆ H ₆ O ₇ Reddish brown leaf crystal ⇒ Difficult to water ⑤ Aluminum citrate AlC ₆ H ₅ O ₇ Oolong Crystal ⇒ dissolved in hot water

When citric acid is used in cement, it is mixed with cement powder or dissolved in water before use in mortar or concrete.

In the present invention, unlike the role of citric acid, which is known to be applicable in the field of cement, the toxic Na ₂ which is usually present in the glass tube in the capillary hole of the hardened cement due to the chemical reaction of citric acid, that is, a relatively strong organic acid, that is, a neutralizing action. It was found to reduce strongly alkaline substances such as O and K ₂ O and Ca (OH) ₂ , and was used to lower the pH of the hardened cement. In addition, citric acid emits an orange fragrance so that there is no irritating odor of the cement to obtain an environmentally friendly cement hardening body.

Dissolve citric acid in distilled water and measure the pH by concentration;

0.01%: 4.98, 0.05%: 4.42, 0.1%: 3.61, 0.15%: 3.31, 0.2%: 3.15, 0.25%: 3.04, 0.3%: 3.03, 0.35%: 2.94, 0.4%: 2.91, 0.45%: 2.89, 0.5%: 2.82

Meanwhile, in the present invention, tartaric acid (Tartaric acid, dihydroxy succinic acid) is used as an organic acid which can be added together or alone with citric acid powder, tartaric acid is colorless transparent crystal or white powder, odorless acid taste, stable in air Do. Density 1.76, m.p. 170 ℃ and soluble in water.

A dibasic acid having two OH groups in the molecule is represented by _{HOOC (CH 2 O) 4 COOH} .

Isomers such as L, D, and meso forms, are naturally distributed in the form of glass, Ca-salts, and K-salts in fruits and plants, and are environmentally friendly organic acids widely used in confectionery and foods along with citric acid. to be.

The pH of tartaric acid was as follows.

0.01%: 6.41, 0.1%: 5.06, 0.2%: 4.58, 0.3%: 4.32, 0.4%: 3.63, 0.5%: 3.47, 0.7%: 3.31, 1%: 3.28, 1.5%: 2.84, 2%: 2.31 It has a slightly lower acidity than citric acid.

The tartaric acid is dissolved in water and ionized as follows, and dissociates into the tartaric acid group and 2+ to 4+ ions as shown below.

HOOCCHOHCHOHCOOH → OOCHOHCHOHCOO ^{- +} 2H + or OOCHOCHOCOO ^{- +} 4H +

This anion-charged tartaric acid group reacts with weak alkaline substances such as water-soluble Ca, Na, and K compounds to form salts thereof.

Salts expected when tartaric acid is used in cement include potassium stannate (K ₂ C ₄ H ₄ O ₆ ), calcium stannate (CaC ₄ H ₄ O ₆ ), calcium stannate (Ca (HC ₄ H ₄ O ₆ ) ₂ ), tartaric acid Sodium (Na ₂ C ₄ H ₄ O ₆ );

As described above, the organic acids used in US Pat. Nos. 2,174,051, 2,542,364, and 3,656,985 to improve the coagulation delay effect, water sensitization effect, fluidity and workability of cement are citric acid, tartaric acid, sugar acid, tetrahydroxy adipic. It was 2-3 basic acids which have OH groups, such as an acid, and these Na or Ca salts. Among them, the highest acidity is citric acid consisting of one OH group and three carboxyl groups, followed by tartaric acid consisting of two OH groups and two carboxyl groups. Since sugar acid is a generic name of tetrahydroxy dicarboxylic acid obtained by oxidation of ald hexsose, tetrahydroxy adipic acid is also an acid belonging to the same class as the sugar acid represented by HOOC (CH ₂ O) ₄ COOH. These acids and salts cannot be used in the present invention because their salts are close to neutral as well as degraded.

US Pat. No. 3,656,985 describes tartaric acid as the most effective acid among the hydroxylated carboxylic acids used in cement in view of the improvement of coagulation delay, water resistance, fluidity and workability. It is.

In the present invention, such citric acid and tartaric acid are preferably added in an amount of 0.01 to 1.5 parts by weight based on 100 parts by weight of the total content of portland cement and light. If the amount is more than 1.5 parts by weight, the acid is too strong and various chemical side effects may occur. If it is added less than 0.01 parts by weight, the amount may be too small to cause a desired chemical reaction.

In the present invention, the above-mentioned citric acid is included together with the light.

This mineral is a clay mineral produced in large quantities in Chungbuk, Korea, and its chemical formula is generally represented as KyAl ₄ (Si ₈ .y, Aly) O ₂₀ (OH) ₄ . Where y is less than 2, usually in the range of 1 to 1.5%.

According to the analysis table of the light from the D mine of Youngdong Material, SiO ₂ 57.03%, Al ₂ O ₃ 23.023%, CaO 0.43%, Fe ₂ O ₃ 2.97%, K ₂ O 5.79%, MgO 1.60%, Na ₂ 5.703% O, 0.007% Mn, 0.38% TiO ₂ , 0.10% P ₂ O ₅ , 8.4% Igiloss and so on.

In addition to the villus, mica-type clay minerals are the mainstream. Especially, the alumina (Al ₂ O ₃ ) content is high, and generally K amount and moisture are high, so there are many hydrous mica forms, and mineral particles are two layers. It is either octahedral or three-layered octahedron, with weak K ⁺ ions between the layers and the surface of the particles charged with OH ⁻ ions. The minor constituents are clay minerals with montmorillonite, muscovite, kaolinite, sericite, etc. SiO ₂ and Al ₂ O ₃ are composed of crystals and amorphous materials.

This mineral has a pH of about 7.5 and is widely used as a soil improver, heavy metal adsorbent, and animal feed additive. According to the literature, it adsorbs toxic substances, bacteria, and alkaloids, making it environmentally friendly.

The amount of amorphous constituents causing pozzoran reaction in the light was estimated to be 25-30% and was dissolved in 5% HCl more than 10% NaOH. However, it does not dissolve in citric acid and tartaric acid which are organic acids.

In the present invention, the addition of the elite can reduce the toxic Ca (OH) ₂ which is usually present in the capillary hole of the cement hardened body together with the citric acid due to the pozzoran reaction of the elite, in addition to the toxic substance, It is intended to exhibit the characteristics of the strong light adsorption to bacteria and the like.

In the present invention, such light is contained in an amount of 10 to 50% by weight relative to 90 to 50% by weight of cement powder. If the content of the light is less than 10% by weight, the specific reactivity of the light is too weak, and 50% by weight. If exceeded, the average particle size of the ilite is much lower than that of Portland cement, which may cause problems in the adhesion of the cement to the yrite powder.

On the other hand, the mixed cement of the present invention can replace some of the above-described light, such as fried ash, clay, slag, volcanic ash and the like, and may be added to a substance having a high content of Silica and alumina and causing a pozzoran reaction.

The addition amount is preferably 10 to 40% by weight of the total content of the Portland cement powder and the light powder, and if the addition amount is out of the above range, the amount of the light is too small or excessive to play a role of the present invention. There may be a problem out of the way.

Such an environmentally friendly mixed cement of the present invention can be obtained by simply mixing Portland cement powder, light powder, organic acid powder, etc., but in order to improve productivity, the process of preparing the Portland cement powder by grinding the clinker It is preferable to mix and grind together the ore and the powder of single or mixture selected from citric acid and tartaric acid together.

In order to examine how the mixed cement of the present invention affects the hydration, condensation, curing and pH of the hardened body of Portland cement, the hydration, condensation, and curing of Portland cement was described in detail based on various documents. On the basis of this, when describing the step-by-step impact of the present invention cement is as follows.

(1) Brief summary of hydration, condensation, and hardening of cement

Portland cement powder is composed of clinker and about 3 ~ 5% dihydrate gypsum (CaSO ₄ · 2H ₂ O). The main chemical percentage of clinker is C ₃ S 45 ~ 52%, C ₂ S 24 29%, C ₃ A 8-11%, and C ₄ AF 8-10%.

In addition and as an alkali component-containing degree _{MgO 1.10 ~ 1.16%, Na 2} O 0.03 ~ 0.09%, K 2 O 0.05 ~ 0.18%.

To summarize the hydration of Portland cement, the hydration of C ₃ S reacts vigorously for a few minutes immediately after the coma, but C ₃ S reacts with gypsum to produce high sulfate calcium aluminate, ie, Ettring Guide. The hydration of C ₃ S enters the Humin phase for about 10 minutes by surrounding the ₃ A particles. However, the ettring guide has a high self-expansion force and is revived by the crack of the ettring guide's coating that surrounds the CS ₃ particles. In the process of repeating this process, the number of bonds rapidly increases, and Ca ²⁺ ions and Si ions are dissolved in the liquid phase, and Ca ²⁺ ions become supersaturated.

This process, namely the hydration condensation of C ₃ S, C ₂ S, the hydration condensation of calcium aluminate, and the hydration of C ₃ A-gypsum and lime hydroxide systems as mentioned in the above-mentioned hydration, condensation and curing of Portland cement. Condensation, hydration condensation of calcium ferrite, reactions, etc. are made into a heterogeneous reaction and enter the curing step.

In order to find out how the mixed cement of the present invention affects the hydration, condensation, and curing of cement paste, a penetration tester having a weight of 300.3 g and a needle diameter of 1.1 mm was manufactured in accordance with the Vicat penetration tester to produce KS L5102 and KS L5108. The results of the penetration test according to the results are shown in Table 2 below.

Invasion Dildo Test Sample Number Sample name Acid addition amount (%) Opening time (minutes) End time (minutes) Acid addition amount (%) Opening time (minutes) End time (minutes) Acid addition amount (%) Opening time (minutes) End time (minutes) One PC90 + I10 CA 0.01 240 555 CA0.25 240 540 CA0.5 330 585 2 PC80 + I20 225 540 225 480 345 570 3 PC70 + I30 250 555 225 525 330 570 4 PC60 + I40 250 540 210 510 315 555 5 PC5 + I50 225 510 210 495 270 540 6 PC90 + I10 TA 0.2 225 525 TA0.75 300 540 TA1.5 345 600 7 PC80 + I20 225 540 315 525 330 585 8 PC70 + I30 195 510 300 525 330 570 9 PC60 + I40 210 495 285 540 285 570 10 PC50 + I50 210 480 285 510 270 555 11 PC50 + I10 + FA20 + S20 CA0.01 240 555 CA0.25 315 555 CA0.5 330 585 12 PC50 + I20 + FA15 + S15 225 540 285 525 330 570 13 PC50 + I30 + FA20 225 510 285 525 345 570 14 PC50 + I40 + S10 210 525 300 510 300 540 15 PC50 + I40 + FA10 195 480 270 525 315 555 16 PC50 + I10 + FA20 + S20 TA0.2 240 540 TA0.75 315 555 TA1.5 360 585 17 PC50 + I20 + FA15 + I15 225 525 300 525 330 585 18 PC50 + I30 + FA20 225 495 300 525 345 555 19 PC50 + I40 + S10 210 510 300 540 330 540 20 PC50 + I40 + FA10 225 510 285 510 285 555 PC: Portland Cement, I: Elight FA: Fry Ash, S: Slag CA: Citric Acid, TA: Tartaric Acid

The test results show that citric acid or tartaric acid, as described in the above US patent, delays the hydration and condensation of the mixed cement of the present invention for a considerable time.

The purpose of using citric acid or tartaric acid in the cement of the present invention is not to delay the hydration condensation time but to access the pH of the hardened cement body by neutralization toward the neutral side using the acidity of these organic acids.

In the Vicat Cement Coagulation Penetration Test, KS L5201 usually has more than 45 minutes of initial connection and less than 375 minutes of termination for Portland cement.In Japanese Industrial Standard JISR5201 (physical test method for cement), all cements are 20 ± 3 ℃. However, it is said that after 60 minutes under the condition of over 80% of humidity, the initial start must be completed and finished within 10 hours. The test apparatus is to use the Vicat needle device.

When water and w / c ratio of 0.3 to 0.7 are added to the Portland cement and stirred, it becomes a flowable paste with a slight heat generation, but gradually becomes hard as the fluidity decreases. This is because the clinker minerals that make up the cement particles react with water to develop new tissue. This step is called setting.

Penetration test is to know the degree of condensation. Cement condensation usually starts about 2 hours after hydration and ends at about 4 hours.

After condensation, it hardens, but there is no sensitivity, but it becomes harder and harder. This step is called hardening. The hardened body of cement is comprised by the cement gel produced | generated by taking water by hydration from the mixture of cement and water. This cement gel is a collection of extremely fine crystals, has a large surface area of about 700 times that of cement, and expands to about twice the volume of cement, filling the space filled with water to form a dense hardened body. A ball is created.

In actual construction, mortar or concrete using aggregates is used a lot. Aggregates not only serve as inexpensive fillers, but also relieve shrinkage due to moisture evaporation in cement gel by long-term curing and drying.

In the present invention, citric acid and tartaric acid, which are oxycarboxylic acids, are used in addition to ilite. According to the literature, oxycarboxylic acid molecules or ions are combined with Ca ²⁺ ions to form a strong chelate ring, adsorbed onto the surface of C ₃ S to be used as an elite (CS _It is supposed to delay the sign language of ₃ ).

Table 2 is a measurement of the setting time by the Vicat apparatus using the present invention cement.

As shown in this article, the initialization was started after 1 hour and the finalization was completed within 10 hours, indicating that there is no defect in cement. The higher the cement light content, the faster the finalization time and the shorter termination time. Is showing. Here, citric acid has reached the end time limit of 10 hours (600 minutes) at 0.5% of the amount added, and tartaric acid has reached 600 minutes, which is also 10 hours at the 1.5% range, and the upper limit of the amount of citric acid added is 0.5% It is reasonable to set an upper limit of 1.5%.

In the present invention, citric acid or tartaric acid, which is an oxycarboxylic acid, is used, and its purpose is not to delay hydration condensation as in the US patent, but to control the pH of the hardened cement body from strong alkali to neutral, that is, neutralizing action. In producing an environmentally friendly cement, the addition amount and pH of citric acid and tartaric acid added to the cement are also large factors that influence the performance of the cement of the present invention. As described above, the upper limit of the amount of citric acid and tartaric acid was adjusted to 0.5% (pH 2.82) and 1.5% (3.02), respectively, but it is most appropriate to refer to the pH of each concentration as a factor for determining the lower amount of their addition. It is considered that it is appropriate to set the pH to 5.0 or less, which is lowered from neutral (pH7) to about 2.0. As a result, it was found that the acidity was close to this value. .58), the amount of citric acid added ranged from 0.01 to 0.5% of the weight of cement and the amount of added tartaric acid ranged from 0.2 to 1.5%, and the amount of added acid was 0.01 compared to the use of a mixed powder of citric acid and tartaric acid. It is set in the range of -1.5%.

In general, it is assumed that mixed cement that reacts with Pozoranite has a low initial strength but that the strength after 6 months is higher than that of ordinary cement.

On the other hand, continuous washing with water for 14 days proves that the present invention is an environmentally friendly mixed cement having a pH lower than 10.0. PH measurement of the hardened cement in the present invention is a value measured by mixing the ratio of cement to water (distilled water) in a 1: 1 weight ratio after grinding and drying the mixed cement hardened body.

As described above, a feature of the present invention is to prepare environmentally friendly mixed cement and cement mortar or concrete using citric acid, tartaric acid, and light, which are extremely environmentally friendly materials. same.

In comparison with the actual properties of frying ash, slag, clay, and the like which are currently used as a mixed material in commercially available mixed cements, the light is 7.5-7.61, which is almost alkaline. The pH of frying ash was 10.35, acidic clay was 4.63, and slag was 10.47. The average particle size of commercial light was 11.093㎛, whereas the average particle size of fried ash was 15.016㎛, acidic clay was 14.545㎛, and slag It is 12.789 micrometers.

For reference, the results of measuring the pH and average particle size of Portland cement and slag cement were described. The pH of Portland cement powder was 12.89, the average particle size was 19.596㎛, the pH of slag cement was 12.70, and the average particle size was 12.789㎛.

Considering the advantages of this light based on the pH and average particle size measurements described above; First, as described above, the average particle size is considerably lower than that of cement, frying ash, acidic clay, and slag, so that when the mixed cement is used and cement mortar or hardened concrete is made, the watertightness is improved to make hardened body with relatively high strength. Can be. Second, since the CaO content is almost as low as 0.43%, the CaO content is greatly reduced than the mixed cement made using the frying ash or slag, which has a relatively high CaO content. As a result, the amount of Ca (OH) ₂ in the glass state is reduced. In addition to reducing the effect of whitening is also reduced. In daylight surface is OH ^- are charged ion, and Al ₂ O ₃ as a Ca ²⁺ ion and action to reaction vessel is raised as soon as supersaturated sign because it is much more cement containing about 23% C ₃ S, C A gel such as ₃ A is gradually formed to lead to the curing step.

Citric acid and tartaric acid, on the other hand, act as Ca ²⁺ ions, Na ₂ O, K ₂ O, etc., in addition to the delay in curing, to form poorly soluble citrate in water, greatly reducing the amount of free Ca (OH) _{2 in the} hardened cement. Also, it forms a water-soluble citrate with Na ₂ O, K ₂ O to significantly lower the pH of the hardened cement and at the same time reduce the whitening phenomenon, and has antioxidant properties to prevent corrosion of reinforcing steel in concrete.

As a result of comprehensively reviewing the technical contents as described above, the present invention is a mixed cement citric acid and tartaric acid which is extremely environmentally friendly materials compared to the mixed cement produced by mixing a prior art Portland cement with frying ash, acid clay, slag, etc. Since it is a cement hardened body made of powder and light powder, the initial strength is slightly lower, but after 6 months, the Pozoran reaction, which is higher than Portland cement, and the action of lowering the pH significantly, it was confirmed that the cement was extremely environmentally friendly.

Specifically describing a method for producing an environmentally friendly cement hardened body from such a mixed cement, 10-50% by weight of the light powder is added to 90-50% by weight of Portland cement powder, and the cement powder and the light 0.01 to 1.5 parts by weight of citric acid or tartaric acid powder is added to 100 parts by weight of the total amount of the powder, followed by stirring at room temperature to prepare a mixed cement in which cement and light are uniformly mixed. Then, a small aggregate or a coarse aggregate is added, and water corresponding to a water-cement ratio of 30 to 60% is added to prepare a mixed cement paste and a hardened body. Then, instead of curing directly with water, it undergoes steam curing. Optionally, an additional curing process may be performed. The curing methods include air curing, curing with water, and continuous washing.

Since the mixed cement of the present invention uses citric acid or tartaric acid powder having high solubility in water, it may lose citric acid or tartaric acid when cured by immediately immersing it in water like cement in the curing step. In the case of steam curing for a certain period of time, the chemical reaction of acid should be terminated and then cured with water.If steam curing cannot be performed, such as applying to mass concrete or wall, spray the surface within the range that does not flow water. Or curing in the air as it is.

At this time, citric acid or tartaric acid powder is not added in the mixed cement manufacturing step, and citric acid or tartaric acid powder is added to water having a water and cement ratio of 30 to 60% to prepare an aqueous citric acid solution. You may mix.

In addition, when the mixed cement is manufactured, a substance having a high content of silica and alumina, such as frying ash, clay, slag, volcanic ash, and the like, which causes pozzoran reaction, may be further added.

In the field of application of the mixed cement of the present invention, the concrete field includes mass concrete, such as dams, reef (fish house) concrete structures installed in the sea, prefabricated exterior wall concrete walls, various concrete closed pipes including water taps, telephone poles, railway sleepers and concrete The structure, concrete for the small streams, etc. are mentioned.

In addition, the mortar field includes mortar coating for mortar finishing works for various buildings, lightweight ceiling materials, and lightweight wall materials.

Particularly effective among them is the field of fishes installed in the sea. As mentioned above, according to the estimates of the Korea Cement Processing Association, the concrete reef made of ordinary Portland cement is installed in the sea at a cost of 1.5 trillion won per year. Is not approaching.

The reason why various fish are not approached is that ordinary Portland cement hardener contains about 20% of Ca (OH) _{2, which} is irritating, toxic, and pH 11.45, in the capillary pores. It is considered to be because it is dissolved in and spilled.

However, the concrete reef using the cement of the present invention greatly reduces the amount of Ca (OH) ₂ due to the pozzoran reaction of the elite, the adsorptive power to various bacteria and toxicities, and the formation of calcium salts by citric acid or tartaric acid. Since the pH can be lowered to 10 or less, it is easy to access various kinds of fish and shellfish inhabiting the sea considering that the pH of the seawater is slightly alkaline. The reason is that when the cement and the small aggregate using the cement of the present invention were 1: 2, the cured mortar was pulverized and completely dried, mixed with distilled water in a 1: 1 ratio, and the pH was 10.0 or less. Has great significance. The reason is that concrete contains a lot of coarse aggregates in addition to the small aggregates, so that the pH per unit volume is lower than that of mortar, and because it is installed in the sea, the ratio of concrete and seawater is expected to be 1: 5 to 1:10 or more, so it is relatively pH Because it will be closer to neutrality.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited by the Examples.

Example 1

150 g of mixed cement containing 60% Portland cement powder and 40% light powder in a cylindrical stainless steel container with a 9 cm inner diameter and 10 cm high lid and a citric acid equivalent to 0.1% of the weight of the mixture. Adding powder, closing the lid, and then stirring it uniformly to make 150.15 g of mixed cement; Adding a small aggregate corresponding to twice the weight of cement to 300 g, and then adding 90 g of water having a weight of 60% to the water-cement ratio and stirring to form a mortar cement paste; Injecting it into a mortar mold having a width of 6 cm and a height of 5 cm, and steaming it up and down with an iron rod having a diameter of 7 mm, and then vibrating the upper and lower sides with a vibrator to remove air contained in the cement paste; Left for 24 hours and then the mold is cured for 3 days at a temperature of 30 to 45 ° C. in a steam curing tank in a conventional manner; The mold mortar cured product having a compressive strength of 477 kg / cm 2 and a pH of 10.27 was prepared by demolding and re-inserting the same in a curing tank for 17 days at the same temperature.

Example 2

In the same device and process as in Example 1, 150g of Portland cement and 50% of light cement were mixed in a weight ratio, and citric acid powder having a weight corresponding to 0.01% of the weight of the mixed cement was added to form a mixed cement. , 300 g of small aggregate and 75 g of water, the amount corresponding to 50% of water and cement ratio, were added, and then a cement mortar cured product having a compressive strength of 480 kg / cm 2 and a pH of 10.24 was prepared in the same manner as in Example 1.

Example 3

In the same device and process as in Example 1, 150 g of cement, 50% of Portland cement, 20% of acidic clay, 20% of acidic clay, and 10% of frying ash, was added citric acid powder corresponding to 0.2% of the cement weight. 52.5 g of water having a water and cement ratio of 35% was added thereto, and a cement mortar cured product having a compressive strength of 524 kg / cm 2 and a pH of 10.07 was prepared in the same manner as in Example 1.

Example 4

150g of Portland Cement 50%, 20% Eryrite, 20% Fry Ash, 10% White Clay and 10% clay were mixed by adding the same citric acid powder to 0.4% of the weight of the cement. After cement was added, 60 g of water corresponding to a water-cement ratio of 40% was added thereto, and then a cement mortar cured product having a compressive strength of 490 kg / cm 2 and a pH of 10.02 was prepared in the same manner as in Example 1.

Example 5

By using the same apparatus and process as in Example 1, 50% of Portland cement was added 30% of light and 20% of slag powder to make 150 g of mixed cement, and the citric acid powder and cement having a weight equivalent to 0.3% of the weight of the mixed cement were added thereto. 152.5 g of fine aggregates equivalent to 2.5 times the weight and 60 g of water corresponding to 40% of the water and cement ratio were added thereto, and then a cement mortar cured product having a compressive strength of 497 kg / cm 2 and a pH of 10.08 was prepared in the same manner as in Example 1. It was.

Example 6

150 g of mixed cement to which 50% of Portland cement, 20% of light, 10% of slag, 10% of frying ash, and 10% of acidic clay were added using the same apparatus and process as in Example 1, and this corresponds to 0.3% of the weight of cement. 75 g of water and 300 g of small aggregate corresponding to a citric acid powder, water and cement ratio of 50% were added thereto, and a cement mortar cured product having a compressive strength of 480 kg / cm 2 and a pH of 10.12 was prepared in the same manner as in Example 1. .

Comparative Example 1

Portland cement 50%, Fry ash 50% by mixing the same equipment and process as in Example 1 to make 150g of mixed cement, 60g of water and 300g of small aggregate corresponding to 40% water and cement ratio is added to the same process as in Example 1 In the process, a cement mortar cured product having a compressive strength of 508㎏ / ㎠ and a pH of 11.11 was prepared.

Example 7

In the same device and process as in Example 1, 150 g of mixed cement is made of 50% of Portland cement, 30% of light, 20% of clay, and then a mixed cement is added to the citric acid powder corresponding to 0.15% of the weight of the cement. After adding 320 g of small aggregate and 60 g of water, a cement mortar cured product having a compressive strength of 495 kg / cm 2 and a pH of 10.11 was prepared in the same manner as in Example 1.

Comparative Example 2

300 g of small aggregate and 60 g of water were added to 150 g of cement mixed with 45% of Portland cement and 55% of slag powder by the same device and process as in Example 1, and then the compressive strength was 495 kg / ㎠ in the same manner as in Example 1. And a cement mortar cured product having a pH of 11.23.

Example 8

Citric acid having a weight equivalent to 0.25% of the weight of the mixed cement in 60 g of water corresponding to 40% of water and cement is made by adding 150 g of Portland cement and 50% of light by the same device and process as in Example 1. After adding the aqueous solution of citric acid and 300g of small aggregate dissolved therein, a cement mortar cured product having a compressive strength of 498 kg / cm 2 and a pH of 10.02 was prepared in the same manner as in Example 1.

Example 9

150 g of mixed cement to which 50% of Portland cement, 20% of light, 15% of frying ash, 10% of clay, and 5% of slag were added to the same device and process as Example 1, and 0.3% of 0.3% of the weight of the mixed cement was added. After adding 50 g of citric acid solution and 325 g of a small aggregate in which g of citric acid was dissolved in water, a cement mortar cured product having a compressive strength of 496 kg / cm 2 and a pH of 10.09 was prepared in the same manner as in Example 1.

Comparative Example 3

In the same device and process as in Example 1, 150g of Portland cement and 50% of frying ash are mixed to make 150g of mixed cement, to which 60g of water and 300g of small aggregate are added, and the compressive strength is the same as in Example 1 A cement mortar cured product of 487 kg / cm 2 and pH 11.20 was prepared.

Comparative Example 4

Portland cement 50%, clay 50% mixed cement 150g by adding the same device and process as in Example 1, 60g of water and 350g of small aggregate was added, and the compressive strength of 496㎏ / in the same manner as in Example 1 A cement mortar cured product of cm 2 and pH 11.19 was prepared.

Comparative Example 5

In the same apparatus and process as in Example 1, 150g of cement blended with 50% of Portland cement and 50% of slag powder was made, and then 70g of water and 300g of small aggregate were added thereto. A cement mortar cured product of kg / cm 2 and pH 11.13 was prepared.

Example 10

65 g of citric acid aqueous solution prepared by mixing 150 g of cement of 50% of Portland cement, 40% of volcanic ash, 10% of light, and then dissolving 0.15 g of citric acid powder corresponding to 0.1% of the weight of cement by the same apparatus and process as in Example 1. 320 g of small aggregate was added and stirred to cure in the same manner as in Example 1 to prepare a cement mortar cured product having a compressive strength of 497 kg / cm 2 and a pH of 10.14.

Example 11

Portland cement 50%, light 10%, frying ash 10%, acidic clay 10%, slag 10%, volcanic ash 10% by using the same device and process as in Example 1 after 0.3g citric acid A citric acid solution dissolved in 60 g of water and 330 g of small aggregate were added thereto, and a cement mortar cured product having a compressive strength of 499 kg / cm 2 and a pH of 10.10 was prepared in the same manner as in Example 1.

Example 12

150 g of mixed cement containing 60% of Portland cement powder and 40% of yrite powder was prepared in a cylindrical stainless steel container with a lid of 9 cm inside and 10 cm high with a stirrer, and then the amount of tartaric acid equivalent to 0.7% of the weight of the mixture. Adding powder, closing the lid, and then stirring it uniformly to make 151.05 g of mixed cement; Adding a small aggregate corresponding to twice the weight of cement to 300 g, and then adding 90 g of water having a weight of 60% to the water-cement ratio and stirring to form a mortar cement paste; Injecting it into a mortar mold having a width of 6 cm and a height of 5 cm, and steaming it up and down with an iron rod having a diameter of 7 mm, and then vibrating the upper and lower sides with a vibrator to remove air contained in the cement paste; Left for 24 hours and then the mold is cured for 3 days at a temperature of 30 to 45 ° C. in a steam curing tank in a conventional manner; The mold mortar cured body having a compressive strength of 471 kg / cm 2 and a pH of 10.09 was prepared through a process of demolding again and curing in the same curing tank for 17 days at the same temperature.

Example 13

By using the same apparatus and process as in Example 1, 150g of Portland cement and 50% of light cement were mixed in a weight ratio, and tartaric acid powder having a weight corresponding to 1% of the weight of the mixed cement was added to form a mixed cement. , 300 g of fine aggregate and 75 g of water corresponding to a water-cement ratio of 50% were added thereto, and a cement mortar cured product having a compressive strength of 476 kg / cm 2 and a pH of 10.06 was prepared by the same process and method as in Example 1.

Example 14

In the same device and process as in Example 1, 150 g of cement, 50% of Portland cement, 20% acidic clay, 20% acidic clay, and 10% frying ash was added, and then tartaric acid powder corresponding to 0.2% of the cement weight was added thereto. 52.5 g of water having a water and cement ratio of 35% was added thereto, and a cement mortar cured product having a compressive strength of 501 kg / cm 2 and a pH of 10.27 was prepared in the same manner as in Example 1.

Example 15

150g of Portland cement 50%, 20% light, 20% frying ash, 10% clay and 10% clay was mixed by adding the same amount of tartaric acid powder as 1.5% of the weight of the cement. After cement was added, 60 g of water corresponding to a water-cement ratio of 40% was added thereto, and a cement mortar cured product having a compressive strength of 495 kg / cm 2 and a pH of 10.01 was prepared in the same manner as in Example 1.

Example 16

After adding 30% light and 20% slag powder to 50% Portland cement using the same apparatus and process as in Example 1, 150g of mixed cement was prepared, and then tartaric acid powder and cement having a weight equivalent to 0.5% of the weight of the cement mixed therein. 152.5 g of fine aggregates corresponding to 2.5 times the weight and 60 g of water corresponding to 40% of water and cement ratio were added thereto, and then a cement mortar cured product having a compressive strength of 491 kg / cm 2 and a pH of 10.11 was prepared in the same manner as in Example 1. It was.

Example 17

150 g of mixed cement to which 50% of Portland cement, 20% of light, 10% of slag, 10% of frying ash, and 10% of acidic clay was added using the same apparatus and process as in Example 1, and this corresponds to 0.9% of the weight of cement. 75 g of water and 300 g of small aggregate corresponding to the weight of tartaric acid powder and water / cement ratio of 50% were added thereto, and a cement mortar cured product having a compressive strength of 480 kg / cm 2 and a pH of 10.17 was prepared by the same process and method as in Example 1. .

Example 18

In the same apparatus and process as in Example 1, 150 g of mixed cement was made from 50% of Portland cement, 30% of light, 20% of clay, and then a mixed cement was added to 0.8% of the cement weight. After adding 320 g of small aggregate and 60 g of water, a cement mortar cured product having a compressive strength of 492 kg / cm 2 and a pH of 10.15 was prepared in the same manner as in Example 1.

Example 19

Portland cement 50%, light 30%, white clay 20% made of 150g mixed cement by the same apparatus and process as in Example 1, and 0.4% of the weight of citric acid powder and 0.2% of the weight of cement After adding the tartaric acid powder to the mixed cement, 320 g of small aggregate and 60 g of water were added thereto, and a cement mortar cured product having a compressive strength of 493 kg / cm 2 and a pH of 10.03 was prepared in the same manner as in Example 1.

Example 20

150 g of mixed cement to which 50% of Portland cement and 50% of light were added using the same apparatus and process as in Example 1, and then tartaric acid having a weight corresponding to 0.2% of the weight of the mixed cement in 60 g of water corresponding to 40% of water and cement After adding the aqueous solution of tartaric acid and 300 g of small aggregate in which it was dissolved, a hardened cement mortar having a compressive strength of 490 kg / cm 2 and a pH of 10.15 was prepared in the same manner as in Example 1.

Example 21

150 g of mixed cement to which 50% of Portland cement, 20% of light, 15% of frying ash, 10% of clay, and 5% of slag were added to the same device and process as in Example 1, and 2.25, which is 1.5% of the weight of the mixed cement, was added thereto. 52.5 g of tartaric acid solution in which g of tartaric acid was dissolved in water and 325 g of small aggregate were added thereto, and a cement mortar cured product having a compressive strength of 503 kg / cm 2 and a pH of 10.01 was prepared in the same manner as in Example 1.

Example 22

50 g of a small amount of tartaric acid solution dissolved in 1.5 g of tartaric acid powder corresponding to 1% of the cement weight was made by mixing 150 g of cement of 50% of Portland, 40% of volcanic ash, and 10% of light by the same apparatus and process as in Example 1. Aggregate 320g and stirred to cure by the same process and method as in Example 1 to prepare a cement mortar cured body having a compressive strength of 507kg / ㎠ and pH 10.05.

Example 23

Portland cement 50%, light 10%, frying ash 10%, acidic clay 10%, slag 10%, volcanic ash 10% by using the same device and process as in Example 1 after 1.2g of tartaric acid A tartaric acid solution dissolved in 5.5 g of water and 330 g of small aggregate were added thereto, and a cement mortar cured product having a compressive strength of 497 kg / cm 2 and a pH of 10.15 was prepared in the same manner as in Example 1.

Example 24

Portland cement 50%, light 10%, frying ash 10%, acidic clay 10%, slag 10%, volcanic ash 10% by using the same device and process as in Example 1 and 1.1g of citric acid Citric acid solution dissolved in 23 g of water, tartaric acid solution in which 2.0 g of tartaric acid was dissolved in 27 g of water, and 330 g of small aggregate were added thereto, and a cement mortar cured product having a compressive strength of 487 kg / cm 2 and a pH of 10.06 was prepared in the same manner as in Example 1. It was.

Experimental Example 1

In the composition of Examples 1 to 7 and Comparative Examples 1 to 2, the mixed cement was made for each example, and the amount of water indicated in each was added to make mortar paste in the same manner as in Example 1. It was applied with a thickness of 6mm and left as it was (morning temperature 25 ℃, relative humidity 70%) for 1 month, and cured with natural mortar.

After curing, pH, whitening phenomenon, and degree of irritant odor were measured. The results are shown in Table 3 below.

PH after curing Whitening phenomenon Irritant odor Example One 10.27 slightly radish 2 10.24 slightly radish 3 10.07 radish radish 4 10.02 radish radish 5 10.08 radish radish 6 10.12 radish radish 7 10.12 radish radish compare One 11.11 plenty U 2 11.23 plenty U

Experimental Example 2

Each mortar paste was prepared in each of Examples 8 to 11 and Comparative Examples 3 to 5, and each mortar paste was prepared in the same manner as in Example 1, using the same amount of citric acid solution as in each example. Each was made using a trowel and applied to the concrete wall with a thickness of 7mm and cured mortar by natural curing for 1 month at room temperature 25 ℃ and relative humidity 70%.

After curing, pH, whitening phenomenon, and degree of irritant odor were measured. The results are shown in Table 4 below.

PH after curing Whitening phenomenon Irritant odor Example 8 10.02 radish radish 9 10.09 radish radish 10 10.14 slightly radish 11 10.10 radish radish Comparative example 3 11.20 plenty U 4 11.19 plenty U 5 11.13 plenty U

Experimental Example 3

Mortar molds were prepared and cured by measuring the cement compositions and methods of Examples 1 to 24, and the compressive strength and pH were measured, and the result of the pH measurement after continuous washing for 14 days was shown in Table 5.

Compressive strength (kg / ㎠) PH after 20 days of curing PH after continuous washing Compressive strength (kg / ㎠) PH after 20 days of curing PH after continuous washing Example One 477 10.27 9.96 Example 13 476 10.06 9.81 2 480 10.24 9.94 14 501 10.27 9.95 3 524 10.07 9.85 15 495 10.01 9.80 4 490 10.02 9.67 16 491 10.11 9.83 5 497 10.08 9.84 17 480 10.17 9.90 6 480 10.12 9.90 18 492 10.15 9.91 7 495 10.11 9.89 19 493 10.03 9.79 8 498 10.02 9.53 20 490 10.15 9.87 9 496 10.09 9.84 21 503 10.01 9.56 10 497 10.14 9.89 22 507 10.05 9.64 11 499 10.10 9.76 23 497 10.15 9.80 12 471 10.09 9.80 24 487 10.06 9.64

From the results of Table 5, when the citric acid or tartaric acid is further added to the light powder according to the present invention, it can be seen that the pH is lower depending on the curing, and even lower when continuous washing with water.

From this, it can be seen that when preparing the reef used to be used in the sea water using the cement mixture of the present invention can provide a lower cement, specifically, a cement hardening body of eight pH.

As described in detail above, the mixed cement obtained by adding citric acid powder and lightite powder to the Portland cement powder according to the present invention is not as irritating and toxic as ordinary Portland cement, but rather faint but exhibits fruit flavor. Since it is an extremely environmentally friendly mixed cement, it is expected to be used in various mortars or concrete products in the future, and greatly improve our residential environment. The cement hardened material produced therefrom is used in the capillary hole of hardened material manufactured from ordinary portland cement. The toxic Ca (OH) ₂ present in the state can be greatly reduced by the pozzoran reaction of citrate and the chemical reaction of citric acid. That is, the pH is significantly lower than that of the conventional one, and thus it can be particularly useful for fish field. .

Claims (9)

90 to 50% by weight of Portland cement powder, 10 to 50% by weight of yrite powder, and 0.01 to 1.5 parts by weight of citric acid and tartaric acid corresponding to 100 parts by weight of the total amount of cement powder and yrite powder alone or their Environmentally friendly mixed cement comprising an organic polybasic acid that is a mixture. The environmentally friendly mixed cement of claim 1, further comprising a material selected from frying ash, clay, slag, and volcanic ash such that the content of the cement powder and the light powder is 10 to 40% by weight. A method of producing an environmentally friendly mixed cement by mixing and grinding together a light ore or a mixture of citric acid and tartaric acid or a mixture of citrate and tartaric acid during grinding of the clinker to produce a portland cement powder. The environmentally friendly cement hardening body manufactured from the mixed cement of Claim 1. 5. The environmentally friendly cement hardened body prepared from the mixed cement of claim 1, wherein the environmentally friendly cement hardened body is a fish herb. 90-50 wt% of Portland cement powder is added with 10-50 wt% of yrite powder, and alone or citric acid and tartaric acid selected from 0.01 to 1.5 parts by weight based on 100 parts by weight of the total amount of cement powder and yrite powder. Adding these mixture powders, followed by stirring at room temperature to produce a mixed cement in which cement and light are uniformly mixed; Adding a small aggregate or coarse aggregate to the electrical process and adding water corresponding to a water-cement ratio of 30 to 60% to produce a mixed cement paste; Steam curing the electrical paste; And A method for producing an environmentally friendly cement hardened body, comprising additionally performing one curing step selected from the steps of curing with air, continuous washing, and water. Adding 10-50% by weight of a lightite powder to 90-50% by weight of Portland cement powder and stirring at room temperature to produce a mixed cement in which cement and light are uniformly mixed; In the electric process, a single or a mixture of these powders selected from citric acid and tartaric acid corresponding to 0.01 to 1.5 parts by weight based on 100 parts by weight of the total amount of the cement powder and the light powder was dissolved in water corresponding to the water and cement ratio of 30 to 60%. Adding citric acid and tartaric acid alone or a mixture of these aqueous solutions and small aggregates or coarse aggregates to produce a mixed cement paste; Steam curing the electrical paste; And A method for producing an environmentally friendly cement hardened body, comprising additionally performing one curing step selected from the steps of curing with air, continuous washing, and water. According to claim 6 or 7, characterized in that further selected from the frying ash, clay, diatomaceous earth, slag and volcanic ash so as to 10 to 40% by weight of the cement powder and the light powder content during the process of producing mixed cement. The manufacturing method of the environmentally friendly cement hardened body made into. The method for producing an environmentally friendly cement cured product according to claim 6 or 7, wherein the environmentally friendly cement cured product is a fish herb.