KR101147985B1 - Cementless concrete using blast slag and producing method therof - Google Patents

Abstract

The present invention relates to a cement concrete prepared using blast furnace slag and a method of manufacturing the same, the method of manufacturing cement cement using blast furnace slag according to an embodiment of the present invention, the blast furnace slag, fine aggregates and sugar reducing agent in the mixer A first step of stirring; And a second step of additionally adding the activator, the coarse aggregate and water to the mixer, and stirring the sugar saccharide reducing agent. The sugar reducing agent includes a combination of at least one of melamine-based or lactic acid-based sugar. According to one embodiment of the present invention, it is possible to appropriately control the fluidity and condensation time to secure the concrete workability, it is possible to manufacture environmentally friendly cement concrete with a compressive strength of 25 ~ 80MPa class.

Description

Cementless concrete using blast furnace slag and its manufacturing method {CEMENTLESS CONCRETE USING BLAST SLAG AND PRODUCING METHOD THEROF}

The present invention relates to cementless concrete using blast furnace slag, and a method for manufacturing the same. More specifically, a glucocorticoid prepared by adding sugar to a melamine-based or ligic acid-based water reducing agent is coated in advance on a blast furnace slag as a binder, and then an activator and the like. The present invention relates to a cementless concrete having a fluidity, fluidity duration and setting time sufficient to secure workability by adding the same material, and a method of manufacturing the same.

Globally, many efforts are being made to prepare measures for greenhouse gases, which are currently the main culprit of global warming, and are struggling to prepare such measures in the cement and concrete industries.

As one of such countermeasures, research to replace cement using industrial by-products such as blast furnace slag and fly ash has been continuously conducted. Overseas, the technique of alkali-activated cement (concrete) by polymerization was theoretically established by Davidovits of France in 1978 as a mechanism to have a structure similar to zeolite using kaolinite minerals, but it was put to practical use due to manufacturing problems and economic efficiency. Was not done.

In recent years, cement concrete has been developed that uses blast furnace slag, a by-product of steel mills instead of cement, in connection with the social issues of environmental issues in Australia, the United States, Japan, and Europe. have.

Conventional cement concrete used blast furnace slag 100% instead of cement as a binder, and used an activator of KOH, NaOH, sodium silicate or NaOH and sodium silicate to react the blast furnace slag.

Cemented concrete manufactured using such blast furnace slag and activator shows compressive strength of about 20 ~ 50MPa, but it is difficult to secure workability due to remarkable deterioration of fluidity and initial quickening phenomenon. have.

In addition, in the past, in order to secure workability, a general water reducing agent or a high performance water reducing agent was added, but when used with an alkali activator, the high alkalinity of the alkali activator decreases the effect of the water reducing agent, and the workability and strength are rather deteriorated. There is a problem.

In order to solve the problems of the prior art as described above, the present invention uses blast furnace slag as a binder instead of a large amount of carbon dioxide discharged as a binder, and by adding a saccharide reducing agent to the binder and adding an activator, sufficient to work To provide eco-friendly cementless concrete with its fluidity and proper setting time and compressive strength of 25 ~ 80MPa grade and its manufacturing method.

Cement cement manufacturing method using the blast furnace slag is an embodiment of the present invention for solving the above problems, the step of stirring the blast furnace slag, fine aggregate and saccharide reducing agent in the mixer; And adding an activator, coarse aggregate, and water to the mixer to stir, wherein the sugar reducing agent is composed of a combination of at least one of melamine-based or lactic acid-based sugar.

Preferably, the method may further include curing the stirred mixture in the mixer.

Preferably, the weight ratio of at least one of the melamine-based or lactic acid-based and sugar is 99.5: 0.5 to 98.0: 2.0, the sugar reducing agent is 1.5 to 4.5 parts by weight based on 100 parts by weight of the blast furnace slag, the blast furnace slag The powder degree of is 3300-6200 cm 2 / g.

The activator comprises at least one of sodium hydroxide or sodium silicate.

Cement cement concrete using the blast furnace slag which is another embodiment of the present invention for solving the above problems can be produced by the manufacturing method.

According to the cement concrete of the present invention and a method for manufacturing the same, the working time of the concrete can be properly controlled (for example, 30 minutes to 2 hours) according to the amount of the sugar reducing agent, as well as the setting time of the crude steel portland cement and ordinary portland. It is possible to control the level of concrete using cement.

      In addition, according to the present invention can produce a high-strength concrete with a compressive strength of up to 80MPa when manufacturing the concrete, and because it is very excellent in drying shrinkage and durability, it can be sufficiently applied to concrete structures in place of ordinary concrete using cement, in the future It is possible to manufacture both general strength and high strength concrete in various aspects of the construction site, so it can be widely used.

In addition, according to the present invention, by using the blast furnace slag, which is an industrial by-product instead of cement, as a binder in the production of concrete, not only can suppress the generation of CO ₂ gas discharged in the production of cement, but also by recycling the blast furnace slag The economic burden of securing landfills and environmental pollution from landfills can be prevented.

1 is a graph showing the change in slump over time according to the weight ratio of the water reducing agent and sugar.
2 is a graph showing the condensation time of concrete according to the weight ratio of melamine-based or lignin-based water reducing agent and sugar.
3 is a graph showing the slump of the cement concrete according to the blast furnace slag powder degree.
4 is a graph showing the compressive strength of cementless concrete according to the blast furnace slag powder.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

The raw material of the cement concrete using the blast furnace slag according to the present invention is a glucore slag, activator, fine aggregate, coarse aggregate, water is added to the sugar reducing agent in addition to the binder.

In order to manufacture the cementless concrete according to the present invention using such a raw material, first, the blast furnace slag, fine aggregate, and a sugar reducing agent are added to a mixer and stirred.

The blast furnace slag is preferably used having a powder of 3,300 ~ 6,200cm ² / g. When the blast furnace slag powder is less than 3,300 cm ² / g, the reactivity is low, which is disadvantageous in strength development. When the blast furnace slag is more than 6,200 cm ² / g, it is not effective in increasing the reactivity, and the powder produced in steel mills This is because the economy is deteriorated because it needs to be powdered to become large.

The saccharide sensitizer is composed of a combination of sugar and a sensitizer comprising at least one of conventional melamine-based or lignin-based. Melamine-based or lignic acid-based reducing agents are used to ensure fluidity as in conventional concrete, and sugar is used to delay the reactivity of concrete to maintain fluidity duration.

Melamine or lignin acid-based sensitizer and sugar are mixed in a weight ratio of 99.5: 0.5 ~ 98.0: 2.0 and stirred at a speed of about 100rpm, sugar is completely dissolved to prepare a sugar sensitizer.

At this time, the weight ratio of the melamine-based or lignin-based water-sensitive agent and sugar is most preferably 99.0: 1.0. If the sugar exceeds 1wt%, it is difficult to control the quality because the retardation effect of the concrete is too high. This is because the retardation effect is too small to be ineffective in maintaining the fluidity duration.

    The water reducing agent is melamine-based or lignin-based, naphthalene-based and polycarboxylic acid-based is not included. This is because naphthalene-based sensitizers do not show a significant water-reducing effect, and polycarboxylic acid-based sensitizers are difficult to control due to the excessive coagulation delay effect even when a small amount of sugar is added.

The sugar reducing agent is preferably 1.5 to 4.5 parts by weight based on 100 parts by weight of the blast furnace slag as a binder. When the sugar reducing agent is less than 1.5 parts by weight (ie, the sugar reducing agent is 1.5% of the binder by weight) with respect to 100 parts by weight of the blast furnace slag, it does not contribute significantly to securing concrete fluidity. Not only occurs, but it also adversely affects the strength development due to the delay of the setting hardening.

Next, the activator, coarse aggregate, and water are additionally added to the mixer in which the blast furnace slag, fine aggregate, and sugar sensitizer are stirred, and then stirred to prepare cement concrete through curing.

As described above, in the present invention, the blast furnace slag and the sensitizer are stirred to infiltrate or coat the sensitizer into the blast furnace slag, and then stirred with the activator. As such, the blast furnace slag and the activator are reacted by reacting the blast furnace slag coated with the saccharide reducing agent. It is possible to control the reaction rate of the appropriate, as a result it is possible to ensure sufficient fluidity for the construction work.

Hereinafter, the present invention will be described in detail with reference to Examples. However, embodiments according to the present invention can be modified in many different forms, the scope of the invention should not be construed as limited to the embodiments described below. The embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art.

< Example  One: With a water reducing agent  Effect of Sugar Weight Ratio>

In the manufacture of cement cement using blast furnace slag according to the present invention, in order to analyze the effect of the weight ratio of melamine-based or lignin acid-based sensitizer and sugar on the flowability of cement cement, the weight ratio of melamine-based or lignin acid-based sensitizer and sugar The sugar reducing agent was prepared as 100: 0, 99.5: 0.5, 99: 1, 98.5: 0.15, and 98: 2.

At this time, the blast furnace slag is composed of the same components as [Table 1, constituent components of the blast furnace slag, activator 9M sodium hydroxide (NaOH, purity 98%) and sodium silicate (Na ₂ O and SiO ₂ molar ratio of 1.12, solid content 38.5%, specific gravity 1.39) was prepared by mixing in a 1: 1 weight ratio.

SiO ₂
(%) Al ₂ O ₃
(%) Fe ₂ O ₃
(%) CaO
(%) MgO
(%) SO ₃
(%) lg. loss
(%) density
(g / cm ³⁾ Powder
(cm ² / g) 33.33 15.34 0.44 42.12 5.70 2.08 0.03 2.90 4,500

Blast furnace slag as a binder having the composition as described above, the activator, fine aggregate, coarse aggregate and sugar reducing agent prepared as described above were combined as shown in [Table 2, compounding ratio of cementless concrete]. That is, put the blast furnace slag, fine aggregate and sugar reducing agent as a binder into the mixer and mix for 30 seconds at a speed of 30 rpm to coat the sugar reducing agent on the surface of the blast furnace slag, and then additionally add a material containing an activator, coarse aggregate and water to 50 rpm ~ Cementum concrete was prepared by mixing at 70 rpm for 2 minutes.

water
(W) cement
(C) Blast furnace slag
(BS) Activator
(AA) Fine aggregate
(S) Coarse aggregate
(G) A sugar reducing agent 43 (kg / ㎥) 0 (kg / ㎥) 666 (kg / ㎥) 116 (kg / ㎥) 513 (kg / ㎥) 1045 (kg / ㎥) BS × 2.0% wt

1 and 2 are the results measured for the slump over time change and the setting time of the concrete prepared by the mixing ratio. 1 is a graph showing the slump change according to the weight ratio of the reducing agent and sugar with time, Figure 2 is a graph showing the condensation time of concrete according to the weight ratio of melamine-based or lignin acid-based reducing agent and sugar. Here, the slump over time change test was performed for 120 minutes immediately after discharging from the mixer by mixing concrete according to KS F 2402, and the setting time was based on the test method of the protruder penetration resistance defined in KS F 2436. Each time a certain time has elapsed, the required load is required to push the penetration into the depth of 25mm, and the time obtained by dividing the area of penetration by 3.5MPa is the initial time and 28.0MPa as the termination time.

Referring to FIGS. 1 and 2, when the conventional cementless concrete, that is, no sugar reducing agent is used (when the weight ratio of sugar reducing agent to sugar is 100: 0), a rapid decrease in fluidity and sudden occurrence of the rapid occurrence are found. Can be. Therefore, cementless concrete produced without using a sugar reducing agent will be difficult to secure workability.

When manufacturing cementless concrete using sugar sensitizer prepared by mixing melamine-based or lignin acid-based sensitizer with sugar, fluidity (slump) and condensation time when the weight ratio of melamine-based or lignin acid-based sensitizer and sugar is 99.5: 0.5 In some degree of effect for ensuring the workability, it can be seen that the construction properties are not sufficient, such as the fluidity is much reduced after 30 minutes.

In the case where the weight ratio of the melamine-based or lignin acid-based sensitizer and the sugar was 99.0: 1.0, the slump was 111 mm after 1 hour, and 80 mm was maintained even after 2 hours, and the end time was 12.8 hours.

When the ratio of melamine-based or lignin-based sensitizer and sugar was 98.5: 1.5, 98: 2, the slump decrease was hardly observed even after 2 hours, but the liquidity was sufficiently secured, but the termination time was 27.8 hours, respectively. And 36.8 hours, it appears that there is difficulty in quality control, such that concrete hardening does not occur even after 1 day.

Taken together, the sugar-sensitive agent prepared in the ratio of melamine-based or lignin-based sensitizer and sugar at 99: 1 improves the fluidity of the concrete, and it is possible to secure sufficient workability up to 2 hours after the concrete is produced. 12 hours is considered appropriate. Therefore, it is most preferable that the ratio of melamine-based or lignin-based water reducing agent and sugar used in manufacturing cementless concrete is 99: 1.

< Example  2: Effect of Sugar Reducing Agent>

In the manufacture of cementless concrete using blast furnace slag according to the present invention, to determine the effect of the use of the sugar reducing agent on the slump and the setting time of the concrete, the sugar reducing agent is 0wt%, 1.0wt%, 1.5 for the binder (blast furnace slag) The mixture was analyzed by wt%, 2.0 wt%, 3.0 wt%, 4.0 wt%, 4.5 wt%, 5.0 wt%. In this case, the materials used, the production method, and the mixing ratio of the blast furnace slag, activator, aggregate, etc. are the same as in <Example 1>.

The slump and solidification time measurement results of the cement concrete according to the amount of the sugar reducing agent are as shown in [Table 3, Slump and setting time of the concrete according to the amount of the sugar reducing agent].

Amount of sugar reducing agent
(wt%) Slump (mm) Set time (hrs) Right after manufacturing 1 hour later First closing 0 32 0 1.2 1.6 One 56 23 6.3 8.3 1.5 95 78 7.8 10.9 2.0 120 111 9.8 12.8 3.0 134 127 10.2 13.5 4.0 162 135 12.7 16.8 5.0 157 123 15.8 22.2

As can be seen in Table 3, it can be seen that the slump and setting time of the concrete increases as the amount of the sugar reducing agent increases.

When no sugar sensitizer was used at all, it was very difficult to secure workability since the slump was 0 after 1 hour, and even when the amount of the sugar sensitizer was 1wt%, it was found that the slump value was not sufficient to secure the workability.

On the other hand, as the amount of sugar reducing agent increased from 1.5wt% to 4.5wt% with respect to the binder, the slump and the setting time increased, and this increased slump and setting time was sufficient to secure workability.

However, when the amount of sugar-sensitive agent is 5wt% or more relative to the binder, the slump was reduced, the setting time was significantly delayed, and the material separation was also severe.

Therefore, in order to improve the workability by securing the fluidity and proper curing time of the concrete without separating the material, a sugar reducing agent containing a melamine-based or lignin-based water reducing agent in a weight ratio of 99: 1 to the binder (blast furnace slag) It is preferable to use wt%-4.5wt%.

< Example  3: Effect of the order of addition of sugar reducing agent>

In order to analyze the effect of coating the sugar sensitizer presented in the present invention on the surface of the binder, as shown in [Table 4, Material input method when manufacturing the concrete], the effect of the cement sensitizer is prepared by changing the order of adding the sugar sensitizer, and then examine the effect. It was. Here, the materials used and the mixing ratios such as blast furnace slag, sugar reducing agent, and activator are the same as those used in <Example 1> and <Example 2>.

Way First stirring 2nd stirring One Blast furnace slag + fine aggregate + sugar reducing agent Coarse Aggregate + Activator + Water 2 Blast furnace slag + fine aggregate Coarse aggregate + activator + sugar reducing agent + water 3 Blast Furnace Slag + Fine Gluing Agent + Activator + Sugar Reducing Agent + Water Coarse aggregate 4 Blast furnace slag + fine aggregate + activator + water Coarse aggregate + sugar reducing agent

The slump and solidification time of the cement concrete prepared after adding and stirring the materials in the same order as described above are shown in [Table 5, Slump and solidification time of the concrete according to the material input sequence].

Way Slump (mm) Set time (hrs) Right after manufacturing 1 hour later First closing One 120 111 9.8 12.8 2 87 56 8.6 11.2 3 92 75 8.3 11.4 4 89 67 8.2 11.1

Referring to [Table 5], it can be seen that the addition of materials in the order of Method 1 during concrete production has a great effect on improving fluidity. That is, it is most advantageous to secure the fluidity of the concrete by first stirring the blast furnace slag and the sugar reducing agent, and then adding the same material as the activator and stirring the secondary.

For the remaining methods 2 to 4, since the slump value is much lower than the method 1, it can be seen that it is not sufficient to improve the fluidity to ensure workability.

The most advantageous reason for adding and stirring the materials in the order of Method 1 as described above is in terms of fluidity effect, because the sensitizer penetrates into the surface of the blast furnace slag as a binder and the activator reacts with the blast furnace slag after coating on the surface. do. If the activator is added together with or before the sensitizer, it will react rapidly with the binder even before the effect of the sensitizer.

Therefore, the melamine-based or lactic acid-based sensitizer and the sugar-containing sensitizer containing a weight ratio of 99: 1 is added together with the binder and stirred to coat the sensitizer on the surface of the binder. It is judged to be effective in securing construction.

< Example  4: Effect of Type of Reducing Agent>

In the present invention, the sugar reducing agent to be used is prepared by mixing a melamine-based or lactic acid-based water reducing agent with a predetermined ratio. At this time, in order to determine the effect of the sugar reducing agent on the slump and the setting time of the concrete, each reducing agent and sugar of the lignic acid, naphthalene-based and polycarboxylic acid-based was prepared in a weight ratio of 99: 1. In this case, the mixing ratio of the material and the material used for the concrete production is the same as in <Example 1> and <Example 2>.

The slump and solidification time of the cement concrete prepared by using the sugar sensitizer prepared by mixing the above water reducing agents and sugars are as shown in [Table 6, Slump and setting time of concrete according to the water reducing agent].

Type of reducer Slump (mm) Set time (hrs) Right after manufacturing 1 hour later First closing Melamine 120 111 9.8 12.8 League acid 118 107 9.3 12.5 Naphthalene system 78 25 6.3 8.4 Polycarboxylic acid system 138 129 19.2 28.1

Referring to [Table 6], the fluidity (slump) and the curing time are sufficient to secure workability when using melamine-based and lignic acid-based reducing agents, but the fluidity of concrete not only decreases significantly when naphthalene-based reducing agents are used. Condensation time also progressed relatively fast, and when the polycarboxylic acid-based sensitizer was used, the fluidity was greatly improved, but the condensation time was delayed a lot and the end of the curing started was more than one day.

Therefore, in consideration of fluidity and proper curing time to secure workability, it is judged that it is appropriate to use melamine-based and lignic acid-based reducing agents in preparing a sugar reducing agent.

< Example  4: Blast furnace slag To powder  Impact>

In the cement concrete manufactured according to the present invention, in order to analyze the effect of the blast furnace slag powder as a binder on the slump and the compressive strength of the concrete, the powder diagram of the blast furnace slag composed as shown in Table 1 is 2,700cm ^{2 / g, 3,300cm 2 / g,} 4,500cm 2 / g, 6,200cm 2 / g, 8,200cm 2 / g and 10,100cm ² / g in the final compound of concrete, the active ingredients other than the blast-furnace slag, sugar water reducing agent And the mixing ratio of the aggregate and the like is the same as in <Example 1> and <Example 2>.

The slump and the compressive strength measurement results of the concrete produced by varying the powder degree of the blast furnace slag as described above are as shown in Figs. 3 is a graph showing the slump of the cement concrete according to the blast furnace slag powder degree, Figure 4 is a graph showing the compressive strength of the cement concrete according to the blast furnace slag powder degree. The compressive strength was made by φ100 × 200mm column test specimen and cured at 20 ℃ for 1 day, followed by curing in air condition (humidity 65 ± 5%), and KS F at 3, 7, 28 and 91 days of age. It measured according to 2405.

Referring to FIG. 3, although the slump is slightly decreased as the blast furnace slag increases, the workability is slightly decreased, but the flowability of the slump up to 8200 cm ² / g is not greatly reduced in the range of 123 to 113 mm. In the case of a powder of 10,100 cm ² / g, the slump was found to significantly reduce the fluidity to about 75mm.

Referring to FIG. 4, it can be seen that when the aging period is the same, the compressive strength increases as the blast furnace slag has a larger powder degree. At 2,700 cm ² / g, the compressive strength was relatively low at 25 MPa or less, even at 28 and 91 days of age. In the case of powders of 8,200cm ² / g and 10,100cm ² / g, the initial strength was slightly improved until 7 days of age, but after that, the strength of powder was lowered compared to 6,200cm ² / g. appear.

Therefore, in conclusion, when manufacturing cementless concrete using sugar-reducing agent, blast furnace slag, activator, etc., it is sufficient workability to use blast furnace slag with powder range of 3,300 ~ 6,200cm ² / g. It is preferable in terms of securing, and it is determined that the cement concrete can be manufactured in accordance with the user's purpose in the compressive strength range of 25 ~ 80MPa. Especially, considering the workability and strength and grinding process, 6,200cm ² / g and 8,200cm ² / g have no difference in terms of strength, so the optimum blast furnace slag powder is 6,200cm ² / It is judged to be g.

Claims (7)

Stirring the blast furnace slag, fine aggregate and the sugar reducing agent in a mixer; And
Including the activator, coarse aggregate and water in addition to the mixer and stirring,
The sugar sensitizer is made of a combination of at least one of melamine-based or lactic acid-based sugar and the weight ratio of at least one of the melamine-based or lactic acid-based and sugar is 99.5: 0.5 ~ 98.0: 2.0 Cemented concrete manufacturing method using The method of claim 1,
Cemented concrete manufacturing method using the blast furnace slag further comprising the step of curing the mixture stirred in the mixer. delete The method of claim 1,
The sugar reducing agent is a cement concrete manufacturing method using blast furnace slag, characterized in that 1.5 to 4.5 parts by weight based on 100 parts by weight of the blast furnace slag. The method of claim 1,
The blast furnace slag powder degree is 3300 ~ 6200 ㎠ / g Cemented cement concrete manufacturing method using the blast furnace slag. The method of claim 1,
The activator is a cement concrete manufacturing method using blast furnace slag, characterized in that it comprises at least one of sodium hydroxide or sodium silicate. Stirring the blast furnace slag, fine aggregate and the sugar reducing agent in a mixer; And adding an activator, coarse aggregate and water to the mixer and stirring the mixture, wherein the sugar reducing agent comprises a combination of at least one of melamine-based or lactic acid-based sugar and at least one of the melamine-based or lactic acid-based The weight ratio of Hana and sugar is 99.5: 0.5 ~ 98.0: 2.0 cement cement using blast furnace slag manufactured by cement cement manufacturing method using blast furnace slag.

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