CN-121800491-B - Cast-in-situ light ceramsite concrete for alpine regions and application thereof

CN121800491BCN 121800491 BCN121800491 BCN 121800491BCN-121800491-B

Abstract

The invention discloses cast-in-situ light ceramsite concrete for alpine regions and application thereof, and belongs to the technical field of building materials. The concrete consists of a cementing material, shale ceramsite, an anti-cracking toughening component (rubber powder and polypropylene fibers), a foaming agent (styrene-acrylic waterproof latex and a composite plant foaming agent) and mixing water. The amidated tea saponin in the composite plant foaming agent and the styrene-acrylic latex produce strong synergistic effect, so that the foam has excellent stability and pore wall strength. The invention ensures that the concrete has higher compressive strength, excellent crack resistance, excellent toughness and high impermeability while keeping low density and good heat preservation property through the coupling of two systems of ATS/styrene-acrylic latex synergistic foam stabilization enhancement and rubber powder/polypropylene fiber synergistic crack resistance and toughening, is especially suitable for severe freeze thawing and temperature difference environments in alpine regions, can be directly used as an integrated functional layer for building roof construction, and synchronously replaces the traditional slope finding, heat preservation, crack resistance and waterproof base layer.

Inventors

SONG JINGYUN
GAO YAN
Liu Baozuo
LU ENYU
ZHAO NING
HU ZHAOXING
WANG XU
CHI JIAN

Assignees

中铁九局集团有限公司

Dates

Publication Date: 20260508
Application Date: 20260310

Claims (8)

1. The cast-in-situ light ceramsite concrete for the alpine regions is characterized by comprising the following components in parts by weight: 340-420 parts of cementing material, wherein the cementing material consists of P.O42.5 cement and class II fly ash; 450-550 parts of lightweight aggregate, wherein the lightweight aggregate is 8-16mm shale ceramsite; 8.8-10.9 parts of anti-cracking toughening component which consists of rubber powder with the particle size of 0.3-0.8mm and polypropylene fiber with the length of 12-19 mm; 18.8-22.8 parts of foaming agent, wherein the foaming agent consists of styrene-acrylic waterproof latex with solid content of 58+/-1% and composite plant foaming agent with solid content of 30-35%; 129-140 parts of mixing water; The composite plant foaming agent accounts for 10-12% of the total weight of the foaming agent, and is prepared by compounding the following components in percentage by weight: 60% -80% of amidated tea saponin; 15% -35% of auxiliary surfactant; 0.1 to 5 percent of high molecular foam stabilizer; The balance being water; the preparation process of the amidated tea saponin comprises the following steps: carboxylation, namely preparing tea saponin into dichloromethane solution, preparing mixed aqueous solution containing 2, 6-tetramethyl piperidine-1-oxygen free radical and NaBr, stirring and mixing the dichloromethane solution and the mixed aqueous solution, and regulating the pH value to 9.5 by using sodium bicarbonate; slowly dropwise adding sodium hypochlorite solution with the effective chlorine content of 10% at the temperature of 0-5 ℃ in an ice bath, continuously monitoring and maintaining the pH value at 9.0-10.0 in the dropwise adding process, and continuously stirring and reacting for 2h after the dropwise adding; after the reaction is finished, separating an organic phase, washing with water, drying with anhydrous sodium sulfate, and concentrating under reduced pressure to obtain a pale yellow solid, namely a carboxylated tea saponin crude product; A2, amidation, namely dissolving the carboxylated tea saponin crude product obtained in the step A1 in anhydrous DMF, adding 1-hydroxybenzotriazole and 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride, stirring and activating for 45 minutes in an ice bath, weighing a primary amine compound and 4-dimethylaminopyridine, dissolving in DMF, slowly dropwise adding an activating solution, removing the ice bath, and stirring and reacting for 12-18 hours at 20-25 ℃; Pouring the reaction solution into ice water, adjusting the volume of the ice water to be 2-3 times of the volume of the reaction solution, adjusting the pH value to be 3 by dilute hydrochloric acid, precipitating a large amount of precipitate, filtering, washing the precipitate by water, then redissolving the precipitate in a small amount of hot methanol, pouring the precipitate into a large amount of acetone for recrystallization under stirring, filtering, and drying in vacuum to obtain an off-white powdery product, namely amidated tea saponin.
2. The cast-in-situ light ceramsite concrete for alpine regions of claim 1, wherein the class II fly ash comprises 20-25% of the total weight of the cementitious material.
3. The cast-in-situ light ceramsite concrete for alpine regions of claim 1, wherein the polypropylene fiber accounts for 10-12% of the total weight of the anti-cracking toughening component.
4. The cast-in-situ lightweight ceramsite concrete for alpine regions, as set forth in claim 1, wherein the auxiliary surfactant is at least one selected from sodium dodecyl sulfate, lauramidopropyl betaine and sodium fatty alcohol-polyoxyethylene ether sulfate, and the polymeric foam stabilizer is at least one selected from hydroxyethyl cellulose, xanthan gum and polyvinylpyrrolidone.
5. The cast-in-situ lightweight ceramsite concrete for alpine regions, as set forth in claim 1, wherein in the step A1, the volume ratio of the dichloromethane solution to the mixed aqueous solution is 0.8-1:1, the weight ratio of the tea saponin, 2, 6-tetramethylpiperidine-1-oxygen free radical and NaBr is 100:0.8-1.2:9-15, and the usage amount of the sodium hypochlorite solution is 5-10% of the total volume of the system.
6. The cast-in-situ lightweight ceramsite concrete for alpine regions, as set forth in claim 1, wherein the molar ratio of carboxyl, 1-hydroxybenzotriazole, 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride and primary amine compound in the carboxylated tea saponin crude product in step A2 is 1:1.1-1.2:1.1-1.2:1.2-1.5, the 4-dimethylaminopyridine accounts for 2-3% of the total weight of the system, and the volume of the activating solution accounts for 10-15% of the volume of the system.
7. The cast-in-situ lightweight ceramsite concrete for alpine regions according to claim 1, wherein the primary amine compound in the step A2 is n-octylamine, laurylamine, myristylamine or palmitylamine.
8. The use of cast-in-situ lightweight ceramsite concrete for alpine regions in integrated construction of building roofs according to any one of claims 1-7, wherein the concrete is used as an integrated functional layer to replace a slope finding layer, a heat preservation layer, an anti-cracking layer and a waterproof base layer in a traditional roof structure synchronously, and is cast-in-situ on a flat roof or a gentle slope roof of a building in a alpine region or a cold region; The construction method of the application comprises the following steps: s1, performing basic layer treatment, namely paving a sliding isolation layer on a building roof; S2, stirring and pumping the cast-in-situ light ceramsite concrete for the alpine region according to any one of claims 1-7 to a roof base layer; S3, leveling the poured concrete by adopting laser leveling equipment; S4, immediately covering the curing material for heat preservation and moisture preservation, wherein the curing time is not less than 7 days; s5, cutting the temperature expansion joint and sealing after the concrete is hardened.

Description

Cast-in-situ light ceramsite concrete for alpine regions and application thereof Technical Field The invention relates to the technical field of building materials, in particular to cast-in-situ light ceramsite concrete for alpine regions and application thereof. Background The weather conditions in the alpine region are severe, the temperature difference between day and night is large, the freeze thawing cycle is frequent, and extremely high requirements are provided for the heat preservation, the water resistance and the durability of the building enclosure structure, particularly the roof. The traditional roof structure adopts a multi-layer method, and is sequentially provided with a slope finding layer, a heat preservation layer, a leveling layer, a waterproof layer and the like, so that the problems of complex construction procedures, long construction period, easy interface stripping caused by the material performance difference of each layer, thermal bridge effect, poor overall crack resistance and the like exist. Cast-in-situ foam concrete or lightweight aggregate concrete is regarded as a potential material for realizing roof integrated construction due to the advantages of light weight, heat preservation, cast-in-place molding and the like. However, the application of common lightweight concrete in high and cold environments faces the key challenges that 1) the internal pore structure is easily damaged under the freeze thawing action, so that the strength attenuation and the heat preservation performance are reduced, 2) the drying shrinkage and the large temperature difference stress are easily cracked, the structural integrity and the water resistance are damaged, and 3) the lower heat conductivity coefficient and the enough mechanical strength and toughness are simultaneously considered. In the prior art, certain properties of concrete are often improved by adding fibers, polymer latex or air entraining agents, but it is often difficult to systematically solve all of the above problems. For example, single fiber toughening has limited effect on inhibiting early plastic shrinkage cracking and does not contribute to improving the pore structure, foam stability generated by common foaming agents is poor, the foam is easy to crack and combine under alkaline cement slurry and pumping shear force to form an uneven and communicated open-cell structure, the impermeability and freezing resistance are seriously damaged, and the toughening and sealing effects of polymer latex are greatly reduced if the polymer latex cannot be well cooperated with a foam system. Therefore, the light concrete material which can adapt to high and cold environments, integrates light heat preservation, high crack resistance, high impermeability and freezing resistance and is suitable for cast-in-situ construction is developed, and has important significance for simplifying roof construction and improving energy conservation and durability of buildings. Disclosure of Invention The invention provides cast-in-situ lightweight ceramsite concrete special for alpine regions, which aims to solve the defects in the prior art. The concrete realizes excellent balance of light weight, heat preservation, crack resistance, impermeability, frost resistance and other performances through unique component design, especially coupling of an amidated tea saponin/styrene-acrylic latex synergistic foam stabilizing reinforcing system and a rubber powder/polypropylene fiber synergistic crack resistance toughening system, can be directly used as a roof integrated functional layer, and synchronously replaces a slope finding layer, a heat preservation layer, a crack resistance layer and a waterproof base layer in the traditional structure, thereby providing cast-in-situ lightweight ceramsite concrete for alpine regions and application thereof. In order to achieve the above purpose, the present invention adopts the following technical scheme: The cast-in-situ light ceramsite concrete for the alpine region comprises the following components in parts by weight: 340-420 parts of cementing material, wherein the cementing material consists of P.O42.5 cement and class II fly ash; 450-550 parts of lightweight aggregate, wherein the lightweight aggregate is 8-16mm shale ceramsite, liaoning Fuxin, chaoyang and the like are selected to produce high-quality ceramsite, the barrel pressure strength is more than or equal to 3.5MPa, the water absorption rate for 1h is less than or equal to 5%, and the mud content is less than or equal to 1.0%; 8.8-10.9 parts of anti-cracking toughening component, wherein the anti-cracking toughening component consists of rubber powder with the particle size of 0.3-0.8mm (the tensile elongation at break is more than or equal to 280 percent, and the source is waste tire normal-temperature grinding rubber powder) and polypropylene fiber with the length of 12-19 mm; 18.8-22.8 parts of foaming agent, wherein the foaming agent consists of st