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CN-117658539-B - Ultra-long-distance pumping concrete and preparation method thereof

CN117658539BCN 117658539 BCN117658539 BCN 117658539BCN-117658539-B

Abstract

The application discloses ultra-long distance pumping concrete and a preparation method thereof, wherein the concrete comprises, by mass, 140-160 parts of cement, 780-810 parts of fine aggregate, 900-1100 parts of coarse aggregate, 180-210 parts of mineral powder, 80-90 parts of fly ash, 160-180 parts of water, 4-8 parts of high-fluidity modifying auxiliary agent and 2-4 parts of polycarboxylic acid water reducer, wherein the molecular chain of the high-fluidity modifying auxiliary agent contains amide groups. The high-flow modifying auxiliary agent forms a three-dimensional adsorption structure on the surface of cement particles, the steric hindrance is large, the aggregation of the cement particles can be effectively prevented, the dispersibility of concrete is improved, the fluidity is obviously enhanced, amide groups in the middle and later stages are gradually hydrolyzed, more free water in the concrete is gradually consumed, the segregation phenomenon is inhibited, and the formed crosslinked reticular structure can continuously maintain the dispersibility of the system.

Inventors

  • Zheng Liande
  • JIN XIN
  • GE JIANWEI

Assignees

  • 杭州山鑫水泥构件有限公司

Dates

Publication Date
20260505
Application Date
20231130

Claims (6)

  1. 1. The ultra-long distance pumping concrete is characterized by comprising the following raw materials in parts by weight: 140-160 parts of cement; 780-810 parts of fine aggregate; 900-1100 parts of coarse aggregate; 180-210 parts of mineral powder; 80-90 parts of fly ash; 160-180 parts of water; 4-8 parts of high-flow modifying auxiliary agent; 2-4 parts of a polycarboxylic acid water reducer; 3-6 parts of hydroxyl-terminated hyperbranched polyester; The molecular weight of the high-flow modifying auxiliary agent is 5000-15000, and the molecular structure is shown as follows: ; The high-flow modified auxiliary agent comprises (1-1.5): (0.8-1.2): (2.5-3) sulfanilic acid, p-cresol, acrylamide and formaldehyde in a mass ratio; the high-flow modified additive is prepared by the following method: S1, adding sulfanilic acid into a sodium hydroxide aqueous solution, adjusting the pH value of the solution to 9-10, and stirring and dissolving at 50-60 ℃ to obtain a sulfanilic acid solution; S2, adding p-toluene phenol into the sulfanilic acid solution, increasing the temperature of the solution to 80-90 ℃, stirring and dissolving, then adding acrylamide, and continuously stirring and mixing to obtain a mixed solution; And S3, dropwise adding formaldehyde into the mixed solution, reacting for 2-3 hours at the constant temperature of 80-90 ℃, then adding an initiator, and continuously stirring and reacting for 6-8 hours to obtain the high-flow modified auxiliary agent.
  2. 2. The ultra-long distance pumping concrete of claim 1, wherein said initiator comprises one or a combination of potassium persulfate, ammonium persulfate, sodium perbromide, benzoyl peroxide.
  3. 3. The ultra-long distance pumping concrete according to claim 1, wherein the addition amount of the initiator is 0.5% -1% of the mass of the acrylamide.
  4. 4. The ultra-long distance pumping concrete according to claim 1, wherein the coarse aggregate comprises crushed stone with a particle size of 10-20 mm and crushed stone with a particle size of 5-10 mm in a mass ratio of 1 (0.6-0.7).
  5. 5. The ultra-long distance pumping concrete according to claim 1, wherein the fine aggregate is medium sand with a fineness modulus of 3.0-2.3.
  6. 6. The method for preparing the ultra-long distance pumping concrete according to any one of claims 1 to 5, which is characterized by comprising the following steps: S1, uniformly mixing cement, fine aggregate, coarse aggregate, mineral powder and fly ash to obtain a premix; and S2, adding water, a high-flow modified additive, a polycarboxylic acid water reducer and hydroxyl-terminated hyperbranched polyester into the premix, and uniformly stirring to obtain the ultra-long-distance pumping concrete.

Description

Ultra-long-distance pumping concrete and preparation method thereof Technical Field The application relates to the field of concrete, in particular to ultra-long-distance pumping concrete and a preparation method thereof. Background The concrete pump can be directly poured, and can realize horizontal and vertical conveying, so that the concrete pump has incomparable advantages for the condition that the construction process is restricted due to the influence of geographical topography factors because of complex surrounding environments. By virtue of the advantages of high construction speed, labor saving, convenience in construction and the like, the pumped concrete gradually becomes a common type in concrete construction, and is widely applied to concrete construction projects of bridge roads, high-rise building structures and the like. Because the long-distance pumping concrete has long transportation time, the concrete is required to have good fluidity, but the high-fluidity concrete is easy to cause bleeding segregation, thereby causing the phenomena of pipe blockage, pipe explosion and the like, not only prolonging the construction period of the engineering, but also greatly increasing the fund investment of the engineering. Disclosure of Invention The application provides ultra-long-distance pumping concrete and a preparation method thereof, which are used for solving the problem that high fluidity and segregation resistance of long-distance pumping concrete are difficult to effectively balance. In a first aspect, the application provides ultra-long distance pumping concrete, which comprises the following raw materials in parts by mass: 140-160 parts of cement; 780-810 parts of fine aggregate; 900-1100 parts of coarse aggregate; 180-210 parts of mineral powder; 80-90 parts of fly ash; 160-180 parts of water; 4-8 parts of high-flow modifying auxiliary agent; 2-4 parts of a polycarboxylic acid water reducer; the molecular structure of the high flow modification aid is shown below. Preferably, the raw materials of the high-flow modifying additive comprise (1-1.5): (0.8-1.2): (2.5-3) sulfanilic acid, p-cresol, acrylamide and formaldehyde in a mass ratio. In the preparation process of concrete, after cement contacts with water, because particles have different charges to attract each other, a cement paste flocculation structure is gradually formed, free water in the concrete is wrapped, so that the free water cannot play a role in the fluidity of the concrete, and bleeding segregation can be easily caused by adding water after the high fluidity of the concrete is maintained, and pipe blockage and pipe explosion are caused. Through adopting above-mentioned technical scheme, the branched chain of high flow modification auxiliary agent is many and long, and the polar group that contains can combine each other with the polar group on cement particle surface to form the solid adsorption structure on cement particle surface, its steric hindrance is big, and the repulsive force between the cement particle will increase, can effectively prevent the gathering of cement particle, thereby impels cement flocculation structure to receive destruction and maintain dispersion state, and the free water of parcel in flocculation structure will release this moment, thereby improves the mobility of concrete. In the process, the high-flow modifying auxiliary agent forms a three-dimensional structure among cement particles so as to have a good dispersing effect, but the free water content in a cement dispersing system is increased, the bleeding rate is increased, and segregation phenomenon is easy to occur. In order to prevent segregation phenomenon, the high-flow modifying auxiliary agent contains amide groups, and in the process of cement hydration, the amide groups in the high-flow modifying auxiliary agent attached to the surfaces of cement particles gradually start to hydrolyze after the temperature of the system is increased, free water in concrete is consumed, polar groups such as carboxyl groups are formed, molecular chains of the high-flow modifying auxiliary agent are broken, the steric hindrance is reduced, short chains of the hydrolyzed high-flow modifying auxiliary agent are crosslinked with each other through hydrogen bonding, and the formed crosslinked network structure can maintain the dispersibility among cement particles, maintain the fluidity of the concrete, increase the cohesiveness of the system and inhibit segregation phenomenon of the concrete. The hydrolysis speed of the amide group in an alkaline environment is slow, the hydrolysis quantity of the high-flow modifying auxiliary agent contained in the early-stage concrete is small in the long-distance transportation process, the dispersibility of the concrete is improved, the fluidity is obviously enhanced, and in the middle and later stages, along with the acceleration of the hydrolysis speed of the high-flow modifying auxiliary agent, more free water i