Talking about the application and construction technology of anti-abrasion concrete for watered (discharged) buildings [Abstract] How to improve the anti-abrasion and erosion resistance of the building's surface protection An important question. In the past, the main surface materials used were epoxy mortar (concrete), cast iron plates, steel plates, and high-grade dry and hard mortar (concrete). The effect was not satisfactory. Silica fume concrete and HF concrete with better effects have been widely used in high-speed water scouring parts of hydraulic structures, and their compressive, anti-abrasion and durability properties have gradually been verified and approved. Based on the application of anti-abrasion concrete in the diversion tunnel project of Xinjiang Kizkar Water Conservancy Project, this paper briefly describes the application and construction technology of anti-abrasion concrete for water (discharge) buildings for reference in similar projects.
[Keywords] Impact resistance tester, Silica fume concrete, HF concrete, Construction technology
Application of HF fly ash anti-abrasion concrete in Kizigaar diversion tunnel project
2.1 Selection of anti-abrasion material Silicon powder anti-abrasion agent is mainly composed of ultra-fine and highly active silicon powder, and it is a composite powder material equipped with abrasion and anti-cavitation additives. It effectively improves the microstructure of concrete, increases the bonding strength between the cement slurry and the sand and stone aggregate interface, increases the tensile and impact resistance of the cement slurry, and can greatly improve the impact resistance of concrete. , Anti-cavitation performance, and significantly improve the mechanical properties, compactness, frost resistance and durability of concrete, while also having the effect of reducing shrinkage and cracking.
HF admixture is a composite of several admixtures. The main components are: ①Water reducing agent, its role is to reduce the water-binder ratio of concrete, increase the strength and consistency of concrete, and thus reduce the slump loss. ② Carrier fluidizing agent, increase the fluidity of concrete, and make the concrete slump constant or little change within 1 to 2 hours. ③Retarder, it acts as retarder and reduces the slump loss of concrete, so that the initial setting time of concrete is prolonged properly, and it has no effect on the strength of concrete after initial setting. ④Concrete expansion agent, using its micro-expansion during the hydration process, to compensate the dry shrinkage of concrete. In general, compared with silica fume concrete, HF concrete has the same compressive strength, erosion resistance and cavitation resistance. Its cohesiveness and water retention are between that of silica fume concrete and ordinary concrete, which overcomes Silica fume concrete has the disadvantage of being too cohesive and not bleeding, and it also improves the poor cohesiveness of ordinary concrete and the ability to easily leak water. HF fly ash concrete mixed with fly ash contains a large amount of glass microbeads in fly ash, which produces a "ball effect" in the mixture, which not only makes the HF fly ash concrete easy to construct and pour, but also easy to compact and compact. The surface can be polished and pumped for pouring, which overcomes the disadvantages of difficult construction of silica fume concrete. In recent years, the price of silica fume is relatively high, and there are fewer manufacturers of silica fume, and the large freight costs have directly caused the price of silica fume concrete to be much higher than that of HF fly ash concrete. Therefore, HF concrete was quickly popularized and applied. HF concrete has been used in dozens of projects, and the results have been well received by most design units, supervision units, construction units and owners.
The 30cm surface of the concrete floor of the diversion tunnel gate in Xinjiang, Kizikal, Xinjiang was originally designed as C60F200W6 silica fume concrete. Taking into account the characteristics of HF fly ash concrete that is superior to silica fume concrete in terms of ease of construction and economy, The design, supervision, construction, and owner units jointly discussed and selected C30F200W6HF fly ash concrete instead of silica fume concrete to meet the anti-abrasion requirements of the floor.
2.2 Application of HF fly ash anti-abrasion concrete in the diversion tunnel project of Kyzkar
2.2.1 Raw materials for construction (1) Sand and gravel Fine aggregate is the natural washed sand sieved in the C2 stockyard planned for this project. The fineness modulus is 2.9, the bulk density is 1530 kg / m3, and the mud content is 1.3%;
Coarse aggregate includes natural pebble (5 ~ 20mm, 20 ~ 40mm) and artificial crushed stone in the C2 stockyard. Pebble (5 ~ 20mm) super radius path content is 4.6% and 5.9% respectively; crushed stone (5 ~ 20mm) super radius path content is 7.5% and 0.6% respectively; cobble (20 ~ 40mm) super radius path content is 3.6 respectively % And 4.2%
(2) Cementing material P.O42.5 cement is used for cement, and its physical and mechanical properties are shown in Table 1. Fly ash is used for grade I fly ash, and its performance test results are shown in Table 2.
Table 1 Test results of physical and mechanical properties of cement
| Cement varieties (specifications) || Standard consistency water consumption (%) || Setting time (min) || Flexural strength (MPa) || Compressive strength (MPa) || Stability (cooked) |
| Initial setting || Final coagulation || 3d || 28d || 3d || 28d |
| P.O42.5 || 28.0 || 143 || 233 || 5.2 || 7.86 || 26.2 || 50.64 || qualified |
Table 2 Fly ash performance test results
| Fly Ash Variety Grade || Fineness (%) || Water demand ratio (%) || Loss on ignition (%) || Water content (%) |
| Grade I || 7.1 || 92 || 4.6 || 0.1 |
(3) Admixture Admixture uses NF-NS-3 pumping agent and NF-1 high-efficiency water reducing agent, air entraining agent uses PMS-NEA3 air entraining agent produced by the company, and HF admixture uses Gansu Jucai Power Technology Co., Ltd. HF admixture produced by the company.
2.2.2 Mixing ratio design test (1) Adaptability test of admixtures The adaptability tests were performed on pumping agent, water reducing agent, HF admixture, and air entraining agent, and it was finally determined that when the amount of fly ash is cement When the dosage is 30%, the optimal dosages of pumping agent, water reducing agent, HF admixture, and air entraining agent are 1.0%, 1.0%, 2.0%, 1.2 / 10000, respectively. The fluidity and the admixtures of water reducing agent and HF admixture have almost the same effect, and can also meet the requirements of pumping concrete.
(2) Determination of mix ratio Under the guidance of Professor Sun of Xinjiang Agricultural University, a C30F200W6 pumped concrete mix ratio test was conducted. The final determination of the mix ratio is shown in Table 3. The 28-day compressive strength was 38.5MPa.
Table 3 C30F200W6 concrete mix ratio
| power level || Water glue ratio || Cementing material (kg) || Sand (kg) || Stone (kg) || Additives (Kg) || Water (Kg) |
| cement || Fly ash || 0-5mm || 5-20mm || 20-40mm || HF (2%) || Air-entraining agent (1.5 / 10,000) |
| pebble || gravel |
| C30F200W6 || 0.38 || 251 || 107 || 746 || 177 || 413 || 483 || 7.16kg || 0.0537kg || 136 |
The mixing ratio was verified by mixing on site at the mixing station, and the determined mixing procedure was:
(Gelling material + HF admixture) Mixing coarse and fine aggregate Mixing (water + air-entraining agent) Mixing 180S, the mixing quality of the mixing station is better. Table 4 shows the quality test results of the mixed concrete.
Table 4 Mixing quality test results
| Workability || Slump || Degree of expansion || Gas content |
| Good workability |
| 190mm || 450mm || 4.9% |
The tester for HKCS-2 concrete anti-sand water flow erosion tester is designed in accordance with the technical requirements specified in the "Hydraulic Concrete Test Regulation DL / T5150-2001". It uses high-speed centrifugal force to rotate the impeller to impact the surface wear of the concrete. In order to determine the ability of various concrete surfaces to resist water impact wear.
1. Sample size: outer diameter 322mm, inner diameter 202 mm, height 60mm
2. Sample container barrel size: φ415 กม 80mm
3. Motor stirring speed: 1430r / min, water flow rate 14.3m / s
4. One flushing time: 0-30min
6. Power supply: AC 380V 50HZ
7. Power: 3KW
8. Volume: 1400 mm กม 800mm กม 500mm
9. Weight: 150kg