JP2005187275A - Fire-resisting and heat-resisting concrete and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fire-resisting and heat-resisting concrete which is not explosively broken even being exposed to a flame, of which thermal conductivity is made low so that main reinforcing bars are not to be at a high temperature, and to which a fire-resisting function in construction is given in a usual manufacturing process. <P>SOLUTION: To 100 pts.mass of the fire-resisting and heat-resisting concrete, one or more of 0.01 to 3.5 pts.mass of a lithium siliceous or a lithium silicate modified solution, 0.1 to 6 pts.mass of a siliceous porous body, 0.04 to 1.1 pts.mass of a sodium silicate modified solution, and also, 0.05 to 2.5 pts.mass of an inorganic fibrous substance, and 0.02 to 1.0 pt.mass of an organic long fiber, are blended. A testing body 20 was heated with a gas burner 11 and its surface temperature reached 1,000°C after 6 minutes. No damages were found when the testing body was observed after 2 hour-heating, and 24 hour-standing still in the air. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a refractory and heat resistant concrete having a refractory performance and a heat resistance performance as high as 1000 ° C. or more and a method for producing the same.

  In civil engineering and construction, the strength of concrete is increasing, and there is a tendency to design the member as thin as possible. However, once a concrete structure hits a fire, the surface of the concrete exposed to the flame suddenly rises in temperature and explodes. The explosion phenomenon that occurs during such a fire occurs more severely in high-strength concrete, and the cover concrete peels off and the main rebar is directly exposed to the flame. In a high temperature range of 1000 ° C. or higher, the strength of the steel material is extremely reduced, and the concrete structure is structurally destroyed.

  In order to prevent destruction of concrete structures due to such fires, use fireproof plates with fireproofing function as interior materials of buildings, or install fireproofing materials etc. so that flames do not hit directly on concrete Yes. However, such measures are costly and time consuming. On the other hand, they cannot cope with the increase in the scale of fire and the change or increase in fire materials, and the fire plate and fire material are warped or peeled off. There is a problem that the flame and heat cannot be sufficiently cut off.

  Therefore, these measures do not exhibit a sufficient fire resistance function.

  Conventional heat-resistant members include fire-resistant bricks, castables, fire-resistant boards, fire-resistant spray materials, etc., but the structure is not strong enough and the price per volume is expensive.

  There is a composite segment in which functional materials such as fireproof, heat insulating, soundproofing, and antifouling are integrally formed on the inner surface side of the tunnel liner segment, and the thickness of the functional material is counted as an effective cover of the reinforcing bar (see, for example, Patent Document 1). ).

  This technology is excellent as a high-performance segment, and uses a functional material that does not wear due to corrosion, does not crack, and does not peel off in the event of a fire. However, the functional material is integrally adhered to the high-strength concrete, but is different from the concrete.

There is also a technology that uses lithium silicate to prevent cracking in the pottery industry.
JP 2003-138894 A (page 2-3, FIG. 1)

  In view of the above problems, the present invention modifies concrete so that it does not explode even when exposed to a flame, and the heat-resistant and heat-resistant concrete having a low thermal conductivity so that the internal main reinforcement does not become high temperature and its production It is intended to provide a method. In addition, this refractory and heat-resistant concrete can be manufactured in the normal process of manufacturing a structure, and is blended with a modifier that has a refractory function from the time of construction even during the manufacturing process, and is relatively inexpensive. Can be produced.

  The present invention provides a groundbreaking structural concrete that has the strength of ordinary concrete or high-strength concrete during normal times, does not require special consideration or curing during construction, and exhibits excellent fire resistance in the event of a fire. To do.

  The present invention has been made to solve the above-described problems, and is a refractory heat-resistant concrete characterized by taking the following technical means. That is, the present invention is a refractory and heat-resistant concrete containing lithium silicate.

  Preferably, the aggregate is one or more selected from the group consisting of natural weight aggregate, natural lightweight aggregate, and artificial lightweight aggregate. Further, if a part or all of the natural lightweight aggregate or the artificial lightweight aggregate is a lightweight aggregate having a specific gravity of less than 1.0, a fire-resistant and heat-resistant concrete having excellent heat insulation is obtained.

  Furthermore, when an inorganic fibrous substance and / or organic long fiber is contained, the toughness is high, and the organic fiber disappears in the event of a fire, and the gas easily escapes.

  The present invention is a refractory and heat-resistant concrete that is provided with a fireproof function during construction and is blended with a relatively inexpensive modifier when a structure is manufactured by a normal manufacturing process. When the inorganic fiber material is further blended in the refractory heat resistant concrete, the resistance to cracking is improved and the heat insulation is improved. In addition, when organic long fibers are mixed, the toughness of the concrete at normal temperature is increased and disappears at high temperature to form a gas escape route.

  The method of the present invention capable of suitably producing the above refractory and heat-resistant concrete of the present invention includes a specific silicic material, aggregate, water and admixture with a siliceous porous material, a lithium siliceous material or a lithium silicate modified solution. A method for producing fire-resistant and heat-resistant concrete, comprising blending to produce concrete.

  It is preferable that the specific hydraulic substance is ordinary Portland cement, early-strength cement, blast furnace cement, alumina cement, or a mixed cement thereof, or a cement whose components are adjusted.

  Addition of one or more selected from the group consisting of silica fume, blast furnace slag fine powder, natural rock fine powder, artificial ceramic fine powder and fly ash fine powder as an inorganic additive increases long-term strength. Can be planned.

  Furthermore, in this manufacturing method, 8 to 35 parts by mass of low heat Portland cement, 3 to 31 parts by mass of ordinary Portland cement, and 0.5 to 31 fine powder of blast furnace slag are used as the specific hydraulic substance with respect to 100 parts by mass of refractory and heat-resistant concrete. 3 parts by mass or ordinary Portland cement and 0.5 to 10 parts by mass of fly ash; 20 to 85 parts by mass of normal aggregate or lightweight aggregate and 3 to 27 parts by mass of water and admixture It is good to mix.

  In this case, the lithium siliceous or lithium silicate modified solution 0.01 to 3.5 parts by mass, the silicic porous material 0.1 to 6 parts by mass, and the sodium silicate modified solution with respect to 100 parts by mass of the refractory and heat resistant concrete. 0.04 to 1.1 parts by mass; Furthermore, it is preferable to mix one or more of 0.05 to 2.5 parts by mass of an inorganic fibrous substance and 0.02 to 1.0 parts by mass of organic long fibers.

  When the natural lightweight aggregate or artificial lightweight aggregate used as the aggregate is blended in a completely dry state or a water absorption state less than half of the water absorption rate specific to the aggregate, a heat-resistant concrete having excellent thermal insulation is obtained. Can do.

  It is preferable that the mixed material further contains an inorganic fibrous substance; and / or one or more organic long fibers selected from the group consisting of polypropylene, acrylic resin, vinyl chloride resin, and polyamide resin (trade name nylon). One or more of 0.05 to 2.5 parts by mass of the inorganic fibrous substance and 0.02 to 1.0 parts by mass of the organic long fiber may be blended.

  According to the present invention, it is possible to obtain a refractory and heat-resistant concrete that does not explode even when exposed to a flame and that has a low thermal conductivity so that the internal main reinforcement does not reach a high temperature. This refractory heat-resistant concrete has a refractory function even in a normal process of manufacturing a structure.

  The present invention has a groundbreaking effect in that it has the strength of ordinary concrete or high-strength concrete at normal times, does not require special consideration or curing during construction, and exhibits excellent fire resistance in the event of a fire. Concrete for concrete.

  The fire-resistant and heat-resistant concrete of the present invention is a fire wall, fire doors, pillars, and concrete member construction methods, flammable storage buildings, road tunnels, fire prevention measures for important structures, high-rise chimneys, public hall structures, disaster shelters Etc. can be used.

  ADVANTAGE OF THE INVENTION According to this invention, the fireproof heat-resistant concrete which does not raise | generate an explosion with respect to the rapid high temperature at the time of a fire, and does not have a possibility of a strength fall is obtained.

  The hydraulic composite according to the present invention has no risk of explosion against overlapping high temperature / flame fires.

  The hydraulic composite of the present invention is more economical, safer and more practical than conventional fireproof coatings and heat-resistant coatings.

  In order to produce the heat-resistant concrete of the present invention, conventional equipment can be used as it is, and no special equipment is required.

  Embodiments of the present invention will be described below.

  The refractory and heat-resistant concrete of the present invention is a refractory and heat-resistant concrete containing lithium silicate, and preferably contains an inorganic fibrous material and / or organic long fiber.

The explosion of concrete (1) is a phenomenon in which the moisture in the concrete rapidly vaporizes and becomes high-temperature and high-pressure steam, destroying the concrete,
(2) A phenomenon in which the silicic acid content of the aggregate causes a difference in the coefficient of thermal expansion from the mortar around the aggregate in the middle temperature range and the high temperature range, destroying the concrete structure,
(3) Phenomenon in which the calcium content in concrete is thermally decomposed and the water generated thereby destroys the concrete structure,
(4) It is said that it is caused by the phenomenon of destroying concrete due to the difference in thermal expansion coefficient between concrete and reinforcing bars, but it is considered that the explosion occurs due to the composite system phenomenon.

  The water inside the concrete decreases with time due to drying. Further, free water decreases as the hydration reaction of the hydraulic material proceeds. However, calcium hydroxide, which occupies the main part of the hardened cement body, decomposes into calcium carbonate and water at around 500 ° C., and the water instantly changes to high-temperature and high-pressure steam. Therefore, if the composition is such that calcium hydroxide is generated as little as possible, the concrete is less likely to explode.

Therefore, concrete using alumina cement with less calcium than normal Portland cement is less likely to explode, but alumina cement has a transition phenomenon near 30 ° C. and is difficult to control strength and is not practical as a structural material. Therefore, the present invention uses any of the following (A), (B), and (C) as the hydraulic substance.
(A) Low heat Portland cement.
(B) What added 5-70 mass% blast furnace slag fine powder to normal Portland cement.
(C) What added 5-30 mass% fly ash to normal Portland cement.

  These hydraulic substances continue the hydration reaction over a long period of time, contributing to the reduction of internal moisture and the improvement of long-term strength.

  Further, lithium silicic acid is used as an additive to react with calcium hydroxide to form an insoluble tricalcium silicate composite, thereby reducing calcium hydroxide.

  Moreover, lithium siliceous material is transformed into a solid solution in a high temperature range exceeding 1000 ° C., and the thermal expansion coefficient of concrete becomes extremely small. Due to the above means and reasons, a modified explosion-resistant concrete can be produced.

  The addition amount of the lithium siliceous or lithium silicic acid modified liquid is 0.01 to 3.5 parts by mass with respect to 100 parts by mass of the refractory heat resistant concrete. If it is less than 0.01 parts by mass, the explosion resistance cannot be improved, and if it exceeds 3.5 parts by mass, it becomes expensive and impractical. More preferably, it is 0.1-1.0 mass part.

  As the lithium siliceous material, “Pentola Seal” (trade name) manufactured by Suruga Kogyo Co., Ltd., “KF # 400” (trade name) manufactured by Kinsei Matec Co., Ltd. may be used.

Lithium silicic acid does not cause a decrease in the strength of concrete and contributes to an improvement in strength. FIG. 2 shows an example of the above, and the above-mentioned “Pentola Seal” (trade name) is added as an example of lithium silicic acid to concrete having a compression strength of 51.50 N / mm ² , and the same conditions as the original concrete. It is a graph which shows the compressive strength of the concrete manufactured by. When 1 to 3 parts by mass of lithium silicic acid is added to 100 parts by mass of concrete, the strength is improved by 10% or more, which is 57 to 58 N / mm ² .

  The refractory and heat-resistant concrete of the present invention can reduce the thermal conductivity of the concrete by adding a siliceous porous body, and at the same time, can reduce network-like cracks due to high temperature history, and alleviate strength deterioration due to high temperature. Can do. Examples of siliceous porous materials include “Taisetsu Balloon” (trade name) manufactured by Biei Shirachi Kogyo Co., Ltd., calcined volcanic ash, shirasu balloon, perlite or vermiculite calcined obsidian, natural and synthetic zeolite, etc. Use it.

  The addition amount of the siliceous porous body is 0.1 to 6.0 parts by mass per 100 parts by mass of the refractory and heat-resistant concrete. If the amount is less than 0.1 parts by mass, the effect of lowering the thermal conductivity is small, and if it exceeds 6.0 parts by mass, the strength is greatly reduced and is not practical. Furthermore, it is preferably 0.3 to 1.5 parts by mass with respect to 100 parts by mass of the refractory heat resistant concrete.

  Further, by adding an appropriate amount of a sodium silicate modified solution, for example, “Crystalizer GW” (trade name) manufactured by KK Crystallizer, the strength reduction rate after a high temperature history can be suppressed to be small and can be improved. The addition amount of the sodium silicate modified solution is 0.04 to 1.1 parts by mass with respect to 100 parts by mass of the refractory and heat-resistant concrete. If the amount is less than 0.04 parts by mass, the strength cannot be improved after a high temperature history. If the amount exceeds 1.1 parts by mass, the cost increases and is not practical. A more preferable addition amount is 0.1 to 0.4 part by mass.

  Addition of artificial mineral fibers (rock wool), amorphous inorganic fibers (asbestos substitutes), etc. as inorganic fibrous materials to improve heat insulation, moisture mobility, lower thermal conductivity, and reduce microcracks Plan. The addition amount of the inorganic fibrous substance is 0.05 to 2.5 parts by mass with respect to 100 parts by mass of the refractory and heat-resistant concrete. If it is less than 0.05 part by mass, the reduction of microcracks after high temperature history cannot be achieved, and if it exceeds 2.5 parts by mass, the kneadability is poor and impractical. A more preferable addition amount is 0.3 to 1.5 parts by mass.

  In addition, organic long fibers such as polypropylene and vinylon may be mixed. Organic long fibers improve the toughness of concrete at room temperature, and when it is heated to around 200 ° C., it melts and vaporizes to form pores in the concrete, creating a escape path for thermally expanded gas. The organic long fiber may have a diameter of 10 μm to 0.3 mm and a length of 3 mm to 30 mm. More preferably, the diameter is 50 μm to 150 μm and the length is 5 mm to 20 mm. The addition amount of the organic long fiber is 0.02 to 1.0 part by mass with respect to 100 parts by mass of the refractory heat-resistant concrete. If the amount is less than 0.02 parts by mass, the effect of escaping the gas is small. If the amount exceeds 1.0 parts by mass, the strength of the concrete is greatly reduced after a high temperature history, and the kneadability is also limited, which is limited. More preferably, it is 0.1-0.5 mass part.

  The aggregate may be a natural aggregate, but an artificial lightweight fired aggregate is more preferable, which contributes to a decrease in the thermal conductivity of the refractory and heat-resistant concrete. As artificial lightweight aggregates, “Mesalite” (trade name) manufactured by Mesalite Industry Co., Ltd., “Asano Superlite” (trade name) manufactured by Taiheiyo Cement Co., Ltd. may be used, and the moisture content is adjusted to 2% or less. As a result, it was found that the thermal conductivity of the concrete can be lowered and the abnormal expansion of the aggregate can be suppressed.

  In the present invention, the raw material of the above refractory and heat-resistant concrete is placed in a mold. It is also possible to produce a composite fire-resistant and heat-resistant concrete by partially placing or pouring or spraying concrete into a structural material.

(Example 1)
Refractory and heat-resistant concrete specimens of the examples of the present invention were produced according to the formulation shown in Table 1. The dimensions of the specimen are 300 mm long × 200 mm wide × 150 mm thick. In Table 1, specimen No. 1 and no. 2 is a comparative example and does not contain lithium silicate. Specimen No. No. 1 is a hydraulic material obtained by adding blast furnace slag fine powder to ordinary cement, using Minano hard sandstone as fine aggregate and Chichibu hard sandstone as coarse aggregate. No. 2 uses an artificial lightweight fine aggregate and an artificial lightweight coarse aggregate.

  Specimen No. 3-No. 9 shows an example of the present invention. 3 is a specimen No. 3. The same hydraulic substance, fine aggregate and coarse aggregate as in No. 1 were used, and lithium silicate was further contained. Specimen No. 4 is a specimen No. 4; No. 3 was further added with “Taisetsu Balloon K” (trade name) manufactured by Biei Shirachi Kogyo Co., Ltd. and organic long fibers as an artificial lightweight aggregate. 5 is No.5. 4 to which “Crystallizer GW” (trade name) manufactured by KK Crystallizer and rock wool are added.

  Specimen No. 6 is a hydraulic material composed of ordinary cement and blast furnace slag fine powder similar to those of Specimen 2; No. 1 natural aggregate and specimen No. 1 2 is a mixture of artificial lightweight aggregates similar to 2, and lithium silicate, inorganic fibers and organic fibers are added.

  Specimen No. 7 is a specimen No. 7. No. 6 natural aggregate replaced with artificial lightweight aggregate, specimen no. No. 8 is an example in which low heat cement is used as the hydraulic material and artificial lightweight aggregate is used as the aggregate. 9 is a specimen No. 9; This is an example in which the hydraulic material 8 is replaced with a material composed of ordinary cement and fly ash.

  These specimen Nos. 1-No. The test which heated 9 was done. The heating test curve followed a RABT curve. The RABT curve is a test curve that is raised to 1200 ° C. in 5 minutes and held, and then lowered to room temperature over 110 minutes after 60 minutes. Table 1 also shows the test results. Specimen No. 1 and no. 2 (Comparative Example) was completely exploded, but specimen No. 2 which is an example of the present invention. 3-No. None of the 9s exploded.

  Moreover, the reinforcing bar position temperature shown in Table 1 is the highest temperature shown during the test at the depth position where the reinforcing bar is arranged. Although the time to reach the maximum temperature is different for each, it is approximately 75 minutes to 110 minutes after the start of heating. As for the reinforced concrete structure, it is desirable that the main rebar temperature is 200 ° C. or less, and the fire resistance performance of the specimen No. 6-No. 9 is very good.

  The compressive strength before the fire resistance test shown in Table 1 is the cylinder strength of 10 cm × 20 cm diameter collected at the same time, and the compressive strength after the fire resistance test is the core boring with a diameter of 45 mm at a position 50 mm lower than the surface from the side of the specimen. It is the intensity | strength of the extract | collected core. The strength change before and after the fire resistance test is the specimen No. 6-No. No change was observed in specimen 9, and specimen no. 3-No. Specimen No. 5 1 and no. The result is superior to 2.

  It is preferable to mix and stir the inorganic fibrous substance and the organic long fiber in the kneading water in advance at the time of kneading, so as to ensure uniform dispersion and kneading.

  In addition, the fire-resistant and heat-resistant concrete of the present invention can also be economically improved by using a concrete surface layer as a fire-resistant and heat-resistant concrete and an inside as ordinary concrete so that the inside and the surface layer are properly used.

(Example 2)
Examples of the present invention were prepared according to the formulations shown in Table 2. In Table 2, the fine aggregate and coarse aggregate are Fujikawa-produced river gravel and river sand, and the lithium-based admixture is “Pentola Seal” (trade name) manufactured by Suruga Kogyo Co., Ltd. As the cement, a type B blast furnace cement manufactured by Nippon Cement Co., Ltd. was used. The water reducing agent is a polycarboxylic acid type, and is “Sea Kament 2200” (trade name) manufactured by Nippon Seika Co., Ltd.

  In accordance with the above formulation, each material was put into a mixer and kneaded, and then mixed water, a water reducing agent, and a lithium-based admixture were added and main kneading was performed. Table 3 shows the results of measuring the physical properties of the ready-mixed concrete after 10 minutes of discharge.

  Further, the above-mentioned ready-mixed concrete was placed in a prescribed form to prepare a specimen having a size of 10 cmφ × 20 cmL. The compressive strength was measured and the results are shown in Table 4.

  Furthermore, the above-mentioned ready-mixed concrete was placed in a mold having a size of 17 cm × 140 cm × 140 cm, and a flat specimen was manufactured. This test body was used for the fire resistance test after 28 days in the air.

  FIG. 1 is an explanatory view showing an embodiment of a fire resistance test. The fire resistance test apparatus 10 is a furnace equipped with a gas burner 11, in which a 140 cm square plate-shaped test body 20 is placed 120 cm upward from the gas burner 11, and the plane is exposed to the flame 12 and heated. .

  The concrete surface of the test body 20 to which the flame 12 from the gas burner 11 hits reached 1,000 ° C. after 6 minutes. The heating time was 2 hours, and the surface layer portion of the test body where the flame 12 hits, the temperature change at three points at a position 3 cm deep from the surface layer portion and a position 7 cm deep were measured. The results are shown in Table 5. The temperature of the surface layer portion reached 1350 ° C., but the temperature rise was slight at a depth of 7 cm.

  After heating for 2 hours, it was left in the air for 24 hours and the appearance was observed, but no damage was observed. The test body was core-bowled and used for the compression test after surface observation. A white discoloration up to a depth of about 1 mm was observed in the surface layer portion where the flame hit, but there was no change in the others. In addition, the strength reduction of this surface layer part was not recognized.

(Comparative Example 1)
According to the formulation shown in Table 6, ready-mixed concrete using artificial lightweight aggregate was prepared. In Table 6, blast furnace cement type B manufactured by Taiheiyo Cement Co., Ltd. was used as the cement. The artificial lightweight fine aggregate and the artificial lightweight coarse aggregate were “Mesalite” (trade name) manufactured by Nippon Mesalite Industry Co., Ltd., and used in an absolutely dry state. The water reducing agent is a polycarboxylic acid type, and is “Sea Kament 2200” (trade name) manufactured by Nippon Seika Co., Ltd.

  According to the above composition, each material was put into a mixer and kneaded, and mixed water and a water reducing agent were added and main kneading was performed to produce ready-mixed concrete, and the physical properties after 10 minutes of discharge were measured. The results are shown in Table 7.

  The amount of air was calculated from the unit volume weight. Furthermore, the above-mentioned ready-mixed concrete was placed in a prescribed form to produce a specimen having a size of 10 cmφ × 20 cmL. The compressive strength was measured. The results are shown in Table 8.

  Furthermore, when the above-mentioned ready-mixed concrete was placed in a mold of 17 cm × 140 cm × 140 cm to produce a flat test piece, the test piece after 28 days of air curing was subjected to a fire resistance test in the same manner as in Example 2. After 10 minutes from the start of heating, the test specimen exploded with a huge sound.

(Example 3)
According to the composition shown in Table 9, the fire-resistant and heat-resistant concrete of the present invention was produced.

  The cement used was a high-strength cement manufactured by Sumitomo Osaka Cement Co., Ltd. The artificial lightweight fine aggregate and the artificial lightweight coarse aggregate are “Mesalite” (trade name) manufactured by Nippon Mesalite Industry Co., Ltd., and the water reducing agent is a polycarboxylic acid-based water reducing agent manufactured by Kao Corporation. “Mighty 2000WHZ” (trade name). The aggregate was used in a state of absorbing water up to half of the water absorption. The lithium-based admixture is “Pentola Seal” (trade name) manufactured by Suruga Industries Co., Ltd.

  In accordance with the above composition, each material was put into a mixer and kneaded, and then mixed water and a water reducing agent were added and main kneading was performed. The physical properties of the obtained ready-mixed concrete after 10 minutes of discharge were measured. The results are shown in Table 10.

  The amount of air was calculated from the unit volume weight. Furthermore, the above-mentioned ready-mixed concrete was placed in a prescribed form, a specimen having a size of 10 cmφ × 20 cmL was obtained, and the compressive strength was measured. The results are shown in Table 11.

  Furthermore, the above-mentioned ready-mixed concrete was placed in a mold having a size of 17 cm × 140 cm × 140 cm, and a flat specimen was manufactured. This test body was subjected to a fire resistance test after 28 days in the air.

  The fire resistance test was conducted in the same manner as in Example 2. The heating time was 1 hour, and the time-dependent changes in temperature at three points, the surface layer portion of the test specimen, the position at a depth of 5 cm, and the position at a depth of 10 cm, were measured from the portion exposed to the flame. The surface layer portion reached 1360 ° C., but the temperature rise was slight at a depth of 10 cm.

  After heating for 1 hour, it was allowed to stand in the air for 24 hours and the appearance was observed, but only a small crack was visible at the center of the surface (surface layer) to which the flame hit, and no other damage was observed. The test body was core-bowled and subjected to a compression test after surface observation. White discoloration with a depth of about 1 to 2 mm was observed in the surface layer portion. There were no other changes. Further, no decrease in strength was observed.

Example 4
According to the formulation shown in Table 13, the refractory heat resistant concrete of the present invention was prepared.

  Blast furnace cement type B manufactured by Taiheiyo Cement Co., Ltd. was used as the cement. “FA Light” is a fine aggregate made of Natsume crushed hard rock (quartz schist) foamed at around 1450 ° C., and coarse aggregate made from Kyuden Sangyo fly ash. (Trade name) was used. The aggregate was used in an absolutely dry state. As the water reducing agent, “Mighty 150” (trade name) manufactured by Kao Co., Ltd., which is mainly composed of a naphthalenesulfonic acid / formalin high condensate salt, was used. The fiber is “Palchip M” (trade name) manufactured by Sugawara Kogyo Co., Ltd., and is a polypropylene type. As the lithium-based admixture, “Pentola Seal” (trade name) manufactured by Suruga Industries Co., Ltd. was used.

  In accordance with the above formulation, each material was put into a mixer and kneaded, and then mixed water and a water reducing agent were added and main kneading was performed. The physical properties of the obtained ready-mixed concrete after 10 minutes of discharge were measured. The results are shown in Table 14.

  The amount of air was calculated from the unit volume weight. Furthermore, the above-mentioned ready-mixed concrete was placed in a prescribed mold, a specimen having a size of 10 cmφ × 20 cmL was obtained, and the compressive strength was measured. The results are shown in Table 15.

  Furthermore, the above hydraulic composite was placed in a mold having a size of 17 cm × 140 cm × 140 cm to produce a flat specimen, and subjected to a fire resistance test after 28 days of air curing.

  The fire resistance test was performed in the same manner as in Example 2 using the fire resistance test apparatus 10 shown in FIG. The heating time was 2 hours, and the change with time of temperature at three points of the surface layer portion of the test specimen, the position of 5 cm depth, and the position of 10 cm depth was measured from the portion exposed to the flame. The results are shown in Table 16.

  After heating for 2 hours and leaving it in the air for 48 hours and observing the appearance, only a slight hair crack was seen in the center of the surface to which the flame hit, and no damage was observed. The test body was core-bowed and the surface was observed, and then used for the compression test. In the surface layer portion, a white discoloration with a depth of about 1 mm was observed, but there was no other change, and no strength reduction was observed in this portion.

(Example 5)
According to the composition shown in Table 17, the fire-resistant and heat-resistant concrete of the present invention containing an aggregate having a specific gravity of less than 1.0 and a special inorganic additive smaller than cement particles was prepared. As the cement, an early strong cement manufactured by Taiheiyo Cement Co., Ltd. was used. The artificial lightweight fine aggregate and the artificial lightweight coarse aggregate are “Mesalite” (trade name) manufactured by Nippon Mesalite Industry Co., Ltd., and the water reducing agent is a polycarboxylic acid-based water reducing agent. “Mighty TH” (trade name). The absolute dry specific gravity of “Mesalite” is less than 1.3. As an aggregate having a specific gravity of less than 1.0, “Microcells” (trade name) manufactured by Chichibu Onoda Cement Co., Ltd. was used. “Microsilica” (trade name) manufactured by Elchem Japan Co., Ltd. was used as the fine powder of the inorganic material. Aggregates and inorganic materials were used in an absolutely dry state. As the lithium-based admixture, “Pentola Seal” (trade name) manufactured by Suruga Industries Co., Ltd. was used. As the fiber, “Brasstron” (trade name) manufactured by Dainippon Ink & Chemicals, Inc. was used.

  In accordance with the above composition, each material was put into a mixer to perform kneading, and then mixed water and a water reducing agent were added to perform main kneading. The obtained ready-mixed concrete had a slump change after 30 minutes of discharge, but the workability was sufficient. Table 18 shows the physical properties 10 minutes after the discharge.

  The amount of air was calculated from the unit volume weight. The hydraulic composite having the above composition was placed in a specified mold, a specimen having a size of 10 cmφ × 20 cmL was obtained, and the compressive strength was measured. The results are shown in Table 19.

  Further, the ready-mixed concrete was placed in a mold having a size of 20 cm × 200 cm × 200 cm to produce a flat specimen. This specimen was subjected to a fire resistance test after 91 days of air curing.

  The fire resistance test was conducted in the same manner as in Example 2 using the apparatus shown in FIG. The heating time was 2 hours, and the change with time of the temperature at the four points on the surface of the test specimen, depth 5 cm, depth 10 cm, and back surface was measured from the portion where the flame hits. The results are shown in Table 20.

  After heating for 2 hours, left in the air for 72 hours and observed the appearance, but there are only small cracks and slight irregularities at the center and end of the surface where the flame hits. I was not able to admit. The specimen was core-bowed and used for the compression test after surface observation. In the surface layer portion, discoloration with a depth of about 2 mm was observed, but no other changes were observed, and no strength reduction was observed in this portion.

(Example 6)
For the formulation shown in Table 17, the fibers were mixed with CEMFIBER “crack stop” (trade name) and Daiwa Boseki Co., Ltd. “Daiwabo PP fiber” (trade name) in a 1: 1 (weight ratio). Used. Furthermore, “775S” (trade name) manufactured by NM Co., Ltd. is used as the AE agent, and “Cell Foam L-50” (trade name) manufactured by Cellfoam Technology Laboratory Co., Ltd. is used as the foaming agent. “Cell Ace” (trade name) manufactured by Cellform Technology Laboratory Co., Ltd. was used.

Each material was put into a mixer and kneaded, and while adding the blended water, water reducing agent and AE agent and carrying out the main kneading, an air amount of 230 liters / m ³ was added to make cellular concrete. The consistency of the obtained ready-mixed concrete did not change until 40 minutes after discharging. Table 21 shows the physical properties after 10 minutes of discharge.

  The amount of air was calculated from the unit volume weight. Furthermore, the above hydraulic composite was cast into a prescribed mold, a specimen having a size of 10 cmφ × 20 cmL was obtained, and the compressive strength was measured. The results are shown in Table 22.

  Further, the above-mentioned ready-mixed concrete was placed in a mold having a size of 20 cm × 200 cm × 200 cm, and a flat test piece was produced. This test piece was subjected to a fire resistance test 91 days after in-air cattle raising.

  The fire resistance test was performed in the same manner as in Example 2 using the fire resistance test apparatus 10 shown in FIG. The heating time was 2 hours, and the change with time of the temperature at the four points on the surface of the test specimen, depth 5 cm, depth 10 cm, and back surface was measured from the portion where the flame hits. The results are shown in Table 23.

  After heating for 2 hours, it was left in the air for 72 hours and the appearance was observed. In addition to the fine cracks and slight irregularities that were observed at the center and end of the flame-struck surface, no damage was observed. The specimen was core-bowed and used for the compression test after surface observation. In the surface layer portion, irregular discoloration was observed up to a depth of about 4 mm, but no other changes were observed, and no strength reduction was observed in this portion.

  The test body used in Example 6 was stored in the air, and a similar fire resistance test was performed again 72 days after the fire resistance test. The heating time was 2 hours, and the specimen after 48 hours in the air was observed and no damage was observed. During heating, steam was ejected from the previously cored portion until about 30 minutes after overheating.

(Example 7)
For the formulation of Example 4, half of the fibers were replaced with rayon fibers of Kyoto fiber material (existing), and the same test as in Example 4 was performed. The results of the refractory experiment were almost the same as in Example 4.

It is explanatory drawing of a fireproof test apparatus. It is a graph which shows the influence which acts on the concrete strength of a lithium-type admixture.

Explanation of symbols

10 Fire Resistance Test Equipment 11 Gas Burner 12 Flame 20 Specimen

Claims (12)

  A refractory and heat-resistant concrete containing lithium silicate.   The fire-resistant and heat-resistant concrete according to claim 1, wherein the aggregate is one or more selected from the group consisting of natural weight aggregate, natural lightweight aggregate, and artificial lightweight aggregate.   The fireproof and heat-resistant concrete according to claim 2, wherein a part or all of the natural lightweight aggregate and the artificial lightweight aggregate is a lightweight aggregate having a specific gravity of less than 1.0.   Furthermore, an inorganic fibrous substance and / or an organic long fiber are contained, The fireproof heat-resistant concrete in any one of Claims 1-3 characterized by the above-mentioned.   A method for producing refractory and heat-resistant concrete, comprising producing a concrete by mixing a siliceous porous material, lithium silicic acid or lithium silicate modified liquid with a specific hydraulic substance, aggregate, water and an admixture.   6. The refractory and heat-resistant concrete according to claim 5, wherein the specific hydraulic material is ordinary Portland cement, early-strength cement, blast furnace cement, alumina cement, or a mixed cement thereof, or a cement in which components are adjusted. Production method.   As the inorganic additive, one or more selected from the group consisting of silica fume, blast furnace slag fine powder, natural rock fine powder, artificial ceramic fine powder and fly ash fine powder are blended. Item 7. A method for producing a refractory and heat-resistant concrete according to Item 5 or 6.   For 100 parts by weight of refractory and heat-resistant concrete, 8 to 35 parts by weight of low heat Portland cement, 3 to 31 parts by weight of ordinary Portland cement and 0.5 to 31 parts by weight of blast furnace slag fine powder, or ordinary Portland cement as the specific hydraulic substance. 3 to 31 parts by mass and 0.5 to 10 parts by mass of fly ash; 20 to 85 parts by mass of normal or lightweight aggregate as the aggregate; and 3 to 27 parts by mass of the water and the admixture. The method for producing a refractory and heat-resistant concrete according to any one of claims 5 to 7.   The lithium siliceous or lithium silicate modified solution 0.01 to 3.5 parts by mass, the silicic porous material 0.1 to 6 parts by mass, and the sodium silicate modified solution 0.04 to 1 with respect to 100 parts by mass of the refractory heat resistant concrete. .1 part by mass is blended, The method for producing a refractory and heat-resistant concrete according to any one of claims 5 to 8.   The natural lightweight aggregate or artificial lightweight aggregate used as the aggregate is blended in a completely dry state or in a water supply state of half or less of the water absorption rate of the aggregate. The manufacturing method of fireproof heat-resistant concrete as described in 2.   6. The mixed material further comprises an inorganic fibrous substance; and / or one or more organic long fibers selected from the group consisting of polypropylene, acrylic resin, vinyl chloride resin, and polyamide resin. The manufacturing method of the fire-resistant heat-resistant concrete in any one of -10.   The fire-resistant and heat-resistant concrete according to claim 11, wherein at least one of 0.05 to 2.5 parts by mass of the inorganic fibrous substance and 0.02 to 1.0 parts by mass of the organic long fiber is blended. Manufacturing method.

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