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CN-121990793-A - Large-volume air-entraining concrete for ship lock and pouring, vibrating and exhausting method

CN121990793ACN 121990793 ACN121990793 ACN 121990793ACN-121990793-A

Abstract

The invention discloses a large-volume air-entraining concrete of a ship lock and a pouring, vibrating and exhausting method, which belong to the technical field of concrete, wherein the large-volume air-entraining concrete of the ship lock comprises 130-160 kg/m 3 of cement, 50-70 kg/m 3 of fly ash, 50-70 kg/m 3 of mineral powder, 600-750 kg/m 3 of sand, 1300-1500 kg/m 3 of crushed stone, 3-5 kg/m 3 of water reducer, 90-130 kg/m 3 of water and 3-4 kg/m 3 of air-entraining and anti-cracking agent according to a mixing ratio; the nanometer-level super absorbent material is used as an air entraining and anti-cracking agent, internal humidity is maintained and temperature peaks are reduced through water absorption and slow water release, and through water release, polymers shrink, corresponding nanometer micropores are reserved in a microstructure, and the air entraining and anti-cracking effects are enhanced.

Inventors

  • XIONG JIANBO
  • TANG BOWEN
  • DING PINGXIANG
  • LI AN

Assignees

  • 中交四航工程研究院有限公司
  • 中交第四航务工程局有限公司

Dates

Publication Date
20260508
Application Date
20260113

Claims (9)

  1. 1. The large-volume air-entraining concrete for the ship lock is characterized in that the raw materials comprise 130-160 kg/m 3 of cement, 50-70 kg/m 3 of fly ash, 50-70 kg/m 3 of mineral powder, 600-750 kg/m 3 of sand, 1300-1500 kg/m 3 of crushed stone, 3-5 kg/m 3 of water reducer, 90-130 kg/m 3 of water, and 3-4 kg/m 3 of air-entraining anti-cracking agent according to the mixing proportion; The preparation steps of the air entraining anti-cracking agent are as follows: s1, preparing a rigid inner core, namely preparing a monomer A and a monomer B through ring-opening metathesis polymerization; s2, grafting the linear outer arm, namely polymerizing a monomer C through an atom transfer radical, and grafting the monomer C to a rigid core to obtain an air entraining anti-cracking agent; The structure of the monomer A is shown in the following formula I: In the formula I, R 1 and R 2 are independently one or more of H, na and K, and a is one or more of integers from 1 to 5; the monomer B has at least one of the following structures in formula II: , In the formula II, R 3 and R 5 are one or more of H, na and K, R 4 and R 6 are one or more of Cl and Br, b is one or more of integers of 1-5, and c is one or more of integers of 1-5; The monomer C has the following structure of formula III: In the formula III, R 7 is at least one of H and methyl, and R 8 is one or more of H and hydrophilic groups.
  2. 2. The lock bulk bleed concrete of claim 1, wherein the water is an ice water mixture having an ice content of 50-70 kg/m 3 .
  3. 3. The large-volume bleed concrete of a ship lock according to claim 1, wherein the preparation step S1 of the bleed crack resistant agent is specifically performed as follows: Dispersing a monomer A, a monomer B and Grubbs catalyst in methylene dichloride in an inert gas atmosphere, adding the methylene dichloride into a reaction kettle, reacting for 30-120 min at the temperature of 25-50 ℃, dispersing the monomer B in the methylene dichloride, adding the methylene dichloride into a reaction system, continuing to react for 30-120 min, adding a terminator to finish the reaction, removing a solvent, washing the obtained solid with alcohol, and drying to obtain the rigid core.
  4. 4. The lock mass bleed concrete of claim 1, wherein the bleed crack resistant agent preparation step S2 is specifically performed as follows: in a reaction kettle, taking the rigid inner core obtained in the step S1 as an initiator, adding a monomer C, a catalyst and a solvent, freezing, thawing and degassing, adding a ligand in an inert gas atmosphere, reacting for 6-24 hours at 50-70 ℃, introducing oxygen to terminate the reaction, removing the solvent, washing the obtained solid with cold methanol, and drying to obtain the air entraining and crack resisting agent; the mass ratio of the monomer B to the catalyst to the ligand is (800-1200): (0.8-1.2): (1.0-2.0); The catalyst is at least one of cuprous bromide and cuprous chloride; The ligand is N, N, N ', N' -pentamethyldi (methyl) ethylene triamine; The solvent is anisole.
  5. 5. The lock mass air entraining concrete according to claim 1 is characterized in that the mass ratio of monomer A to monomer B to monomer C is (8-12): 1-3): 80-120, the mass ratio of monomer A to Grubbs catalyst is (80-120): 0.8-1.2, and hydrophilic groups in monomer C are one or more of polyethylene glycol, polyethylene glycol monomethyl ether and quaternary ammonium salt structures.
  6. 6. The method for pouring, vibrating and exhausting the large-volume bleed air concrete of the ship lock according to claim 1-5, which is characterized by comprising the following steps: 1) Dispersing an air entraining and anti-cracking agent in water, adding cement, fly ash, mineral powder, sand and crushed stone into a cement mixer, stirring for 1-2 min, then adding an ice-water mixture, stirring for 2-5 min, then adding a water reducing agent and the air entraining and anti-cracking agent dispersed in water, and continuing stirring until ice cakes are fully melted; 2) Pouring concrete layer by using a pump truck, uniformly distributing each layer by 30-50 cm, spacing the layers for 2-4 hours, spraying thin-layer water mist on the surface of the lower layer before pouring each layer, and increasing humidity; 3) Vibrating by using a high-frequency plug-in vibrator by using a quick-plug-slow-pull method, wherein the insertion depth reaches 5-10 cm of the lower concrete, the vibrating time of each point is 15-20 s, and the distance is 30-40 cm; 4) In the vibrating process, the surface is slightly vibrated for 5-10 s by matching with a flat plate vibrator, so that the uniform distribution of internal microbubbles is promoted; 5) Cooling water is introduced, the horizontal distance between cooling water pipes is 1.2-1.5 m, the cooling water is controlled at not higher than 20 ℃, the water flow is not less than 2.0m 3 /h, and the cooling water direction is exchanged once in 24: 24 h; 6) Maintaining, namely covering a high-molecular water-saving and moisturizing maintaining film after sprinkling water, then covering a heat-preserving board, and maintaining the heat and moisturizing the elevation, namely covering the high-molecular water-saving and moisturizing maintaining film on the elevation, and preserving the heat of an outer side hanging heat-preserving board or tarpaulin, and structurally sealing a top heat-preserving board, wherein the top spraying maintenance period is not less than 28 d.
  7. 7. The method for pouring, vibrating and exhausting the large-volume air-entrained concrete of the ship lock according to claim 6, wherein in the step 1), the anti-cracking agent is dispersed in water in an amount of 8-12 kg of water per 1 kg anti-cracking agent.
  8. 8. The method for exhausting large-volume bleed concrete pouring, vibrating and locking a ship lock according to claim 6, wherein in the step 3), the vibrating frequency is 100-150 Hz, and the amplitude is 0.5-1.0 mm.
  9. 9. The method for exhausting large-volume bleed concrete pouring and vibrating of a ship lock according to claim 6, wherein the frequency of the flat plate vibrator in the step 4) is 50-60 Hz.

Description

Large-volume air-entraining concrete for ship lock and pouring, vibrating and exhausting method Technical Field The invention belongs to the technical field of concrete, and particularly relates to a large-volume air-entraining concrete for a ship lock and a pouring, vibrating and exhausting method. Background The ship lock is used as a key structure in hydraulic engineering and plays an important role in adjusting water level and guaranteeing navigation. The foundation and the wall are generally poured by adopting large-volume concrete, and the hydration heat release is remarkable due to the large volume and high cement consumption. The heat released by the hydration reaction of the cement can raise the internal temperature of the concrete to 50-70 ℃, and the external temperature difference is larger due to quicker heat dissipation, so that thermal stress is caused. In addition, hydration consumes moisture, early water loss causes self-shrinkage, and the two combined actions easily cause harmful cracks (width >0.2 mm), so that the durability and the safety of the ship lock structure are affected. In order to relieve the temperature difference and shrinkage stress caused by hydration heat, the traditional method comprises the steps of optimizing the mixing ratio (reducing the cement consumption, adding fly ash or slag), pre-burying a cooling pipe (introducing cold water for cooling), pouring in layers and the like. However, these methods have limitations in that the cooling pipe construction is complicated and costly, layered casting may extend the construction period, and it is difficult to thoroughly solve the problem of internal humidity imbalance. In recent years, a super absorbent material (SAP) is introduced into a large volume of concrete as an internal curing agent, internal humidity is maintained and a temperature peak value is reduced through water absorption and slow water release, and through water release, a polymer is contracted, corresponding micropores are reserved in a microstructure, and the effects of enhancing mechanical properties and cracking resistance after air entrainment are achieved. The existing high water absorption material has a certain effect in the aspects of water retention and crack resistance, but has the obvious disadvantages in the application of the lock mass concrete that 1) the air holes are unevenly distributed and the uncontrollable size particle diameter is too large to be in a micron level, the lock mass concrete has high crack resistance requirement, the air holes are required to be uniform and small in size, 2) the particles shrink excessively, the structural stability is poor, the mass concrete needs SAP particles to keep a certain structural stability after dehydration so as to ensure micropore uniformity and matrix mechanical property, and 3) the water release rate is difficult to accurately regulate and control, the mechanical property is insufficient, the compression and the crushing are easy, and the like. Disclosure of Invention In order to overcome the defects in the prior art, the invention provides a large-volume air entraining concrete for a ship lock and a pouring, vibrating and exhausting method, the invention adopts a nanoscale super-absorbent material as an air entraining and anti-cracking agent, the internal humidity is maintained and the temperature peak value is reduced by water absorption and slow water release, and the polymer is contracted by water release, so that corresponding nano micropores are reserved in a microstructure, and the effects of enhancing mechanical properties and cracking resistance after air entraining are achieved. The technical scheme for achieving the purpose is that the lock mass air-entraining concrete comprises, by weight, 130-160 kg/m 3 of cement, 50-70 kg/m 3 of fly ash, 50-70 kg/m 3 of mineral powder, 600-750 kg/m 3 of sand, 1300-1500 kg/m 3 of crushed stone, 3-5 kg/m 3 of water reducer, 90-130 kg/m 3 of water and 3-4 kg/m 3 of air-entraining anti-cracking agent; The preparation steps of the air entraining anti-cracking agent are as follows: s1, preparing a rigid inner core, namely preparing a monomer A and a monomer B through ring-opening metathesis polymerization; s2, grafting the linear outer arm, namely polymerizing a monomer C through an atom transfer radical, and grafting the monomer C to a rigid core to obtain an air entraining anti-cracking agent; The structure of the monomer A is shown in the following formula I: In the formula I, R 1 and R 2 are independently one or more of H, na and K, and a is one or more of integers from 1 to 5; the monomer B has at least one of the following structures in formula II: , In the formula II, R 3 and R 5 are one or more of H, na and K, R 4 and R 6 are one or more of Cl and Br, b is one or more of integers of 1-5, and c is one or more of integers of 1-5; The monomer C has the following structure of formula III: In the formula III, R 7 is at least one of H and methyl, and