RJ-G highway bridge prestressed pore pressure grout
Telephone:13925840771u0026nbsp;Manager Zhang
Product Introduction< /span>:u0026nbsp;
Highway and bridge prestressed pore pressure grout is composed of water reduction, expansion, plastic preservation, reinforcement, segregation resistance, mineral admixtures, etc. A mixture made by dry mixing of two kinds of component materials. After mixing with cement and water in a certain proportion at the construction site, it is used for grouting of post-tensioned prestressed ducts. The customer chooses the grouting agent, and the company will test it with the customer’s Cement compatibility to meet the requirements of construction technical indicators.
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a certain amount of bridge pre-stressed duct grouting agent is homogeneously mixed with cement to become bridge pre-stressed duct pressure slurry, its performance parameters .
一、The road bridge after matching Advantages of prestressed duct pressure slurry products
1. Low water-binder ratio: water The glue ratio is only 0.26～0.28;
2. High fluidity: the initial fluidity of the slurry can be Up to 10S, the fluidity remains within 25S after 60min;
3. High stability: The 24h free bleeding rate of the slurry and the 3h wire bleeding rate are both 0;
4. High resistance Separation: The product meets the requirements of European standard ETAG013, and the simulation test 5m tube has zero bleeding and no defects;
5. Moisture-resistant micro-expansion: the slurry can expand under the moisture-insulating condition in the prestressed pores, compensate for the slurry shrinkage, improve the volume stability of the hardened slurry, and ensure Slurry quality;
6. Early strength and high strength: 3d compressive strength≥20MPa, 28d compressive strength≥50MPa;
7. High durability: 28d electric flux≤1000C, 28d frost resistance grade≥F500. < br/>
Two, material trial matching
Before grouting the pipeline, test the used squeezing slurry in advance Match. The weighing of various materials such as cement, superplasticizer, micro-expansion agent, mineral admixture, water, etc. should be accurate to ±1% (all by mass). The water-binder ratio should not exceed 0.33. After the trial verification test, the slurry can be used only after all the quality indicators of the slurry performance meet the requirements of the above technical parameter table. < br/>
Three, construction equipment and weighing accuracy
1. Construction equipment
The speed of the mixer is not less than 1000r/min, The maximum linear velocity of the leaf is limited to 15m/s. The shape of the blade should match the rotation speed, and can meet the requirements of uniform mixing within the specified time.
The press machine adopts continuous slurry pump. The minimum division value of the pressure gauge should not be greater than 0.1MPa, and the maximum range should make the actual working pressure within the range of 25%-75%.
The storage tank should have a stirring function.
If the vacuum-assisted grouting process is selected, the vacuum pump should be able to achieve a negative value of 0.092MPa pressure.
2, weighing accuracy
When preparing a slurry mixture, the weighing of cement, pressure slurry and water should be accurate to±1 % (All in terms of mass).
Measuring instruments should pass the legal metrological verification and be used within the validity period.
four, mixing process
1. Clean the construction equipment before mixing. There should be no residue or water in the cleaned equipment, and check the filter screen of the mixer. When the compressed slurry enters the storage tank from the mixer, it should pass through the filter screen, and the space of the filter screen should not be larger than 3mm×3mm.
2. The slurry mixing operation sequence is: First, add 80%-90% of the actual mixing water amount to the mixer, start the mixer, add all the pressure slurry evenly, stir while adding, and then evenly add all the cement. After adding all the powder, stir for 2 minutes; then add the remaining 10%-20% mixing water and continue stirring for 2 minutes.
3. After mixing evenly, proceed on site The machine fluidity test is performed once every 10 trays, and the fluidity is within the range specified by the above-mentioned main technical parameters, and it can enter the storage tank through the filter. The slurry should continue to be stirred in the storage tank to ensure the fluidity of the slurry.
No additional water should be added during the construction process due to insufficient fluidity.
Five, grouting process
1. Before grouting, debris and stagnant water should be removed from the beam pores.
2. The slurry is pressed into the beam channel Before, the squeeze pump should be turned on to discharge a little slurry from the squeezing nozzle to remove air, water and thin slurry in the squeezing pipeline. When the fluidity of the discharged slurry is consistent with the fluidity in the mixing tank, it can begin to be pressed into the beam channel.
3. The maximum pressure of grouting should not exceed 0.6MPa. The filling degree of the grouting should reach the fullness of the other end of the tunnel and discharge the slurry with the same degree of fluidity as the specified fluidity from the vent hole. After closing the pulp outlet, a steady-state period of not less than 0.5 MPa and not less than 3 min should be maintained.
4. For continuous beam or pressure compensation When slurrying, let the water-slurry suspension in the pipeline flow freely from the outlet end. Pump the slurry again until there is a homogeneous slurry flowing out at the outlet end, and keep the pressure under a pressure of 0.5 MPa for 5 minutes. This process should be repeated 1-2 times.
5. Check the compaction of the grouting hole in the press/outlet hole. If it is not true, fill it up in time to ensure that the hole is completely dense.
6. If you use vacuum assisted grouting process , Before squeezing, vacuuming should be carried out first to stabilize the vacuum degree in the pores between -0.06MPa and -0.08MPa. After the vacuum is stable, the valve at the squeezing end of the pipeline should be opened immediately, and the squeezing pump should be turned on for continuous squeezing.
7. The grouting sequence is first down and then up , The grouting of the same pipeline should be carried out continuously and completed at one time. The time from mixing the slurry to pressing into the beam should not exceed 40 min.
8. During the grouting process, 3 sets of standard curing test pieces (40mm×40mm×160mm) should be made for each hole beam, and the compressive strength and flexural strength tests shall be carried out. The grouting shall be recorded. The record items should include: grouting material, mixing ratio, grouting date, mixing time, machine fluidity, slurry temperature, ambient temperature, holding pressure and time, (vacuum degree), on-site grouting person in charge, supervisor Engineers, etc.
VI. Construction precautionsu0026nbsp;
Press The temperature of the slurry during grouting should be between 5℃ and 30℃. Within 3 days after grouting and grouting, the temperature of the beam and the environment should not be lower than 5℃, otherwise, maintenance measures should be taken to meet the requirements.
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