The application of Urethane Grout in the overhaul of the skycar track
High-strength non-shrinkage Urethane Grout material is a special material, installation of equipment foundation selection by a special kind of cementing materials and cement aggregate specially processed, density of 190 0 ~ 2100 ㎏ / m 3. Construction is simple, add 16 % ~ 18 % water mix to mix even, depend on oneself flow property can be filled with small fill space. Early strength is growing rapidly, can accelerate the equipment installation and debugging, 28 d compressive strength of more than 70 mpa, 0.02% ~ 0.03% and a micro expansion, do not produce volume shrinkage after hardening, can make be closely linked with the base concrete anchorage parts. Its technical performance reached the level of similar foreign, the performance is better than that of foreign products, has set up a file in the domestic dozens of secondary perfusion engineering applications, have achieved good technical and economic effect, well received by experts both at home and abroad.
In handan iron and steel company, A heavy duty crane structure is A and B columns, with A total length of 288m. The elevation is 14. 800m, span 18.5 m. Overhaul requirements will steelmaking workshop bridge rail replacement for the new track, the original old rail welding with press in [16 short channel steel, channel steel welding on the steel plate, steel plate with bolts and concrete crane beam is an organic whole repeatedly. Overhaul to demolish the old track channel steel, bolt, a new track and bolt. Considering the tight, adopt CGM slurry filling the space between the track plate and support (right).
1. Performance of CGM Urethane Grout
CGM Urethane Grout is a special hybrid material with high fluidity, early strength, high strength and micro expansion. Its performance is as follows.
According to the engineering requirements, the slurry flow is greater than 240mm, and in such a large flow degree, the slurry can be reliable and self-heavy, and a little bit of ramming can flow into all the gaps that need to be filled, and the pulp itself is dense. The flow degree and strength of CGM pulp are measured by different water ratio. According to the actual situation of the project, 18% water ratio was selected for the test, and the results showed that the flow rate of CGM slurry decreased with time. Due to the large amount of engineering, the flow rate in 1.5 h is better.
Slurry principle for micro expansion, a CaO in the slurry, when react with water, heat emission volume increase, because CaO combined with a molecule of water (H 2 O), the volume increases 90%, the large expansion, expansion amount within 1 d CGM size can achieve 80% above, in a stable state after the maximum amount of expansion.
2. Construction preparation
Due to the long use of the track, Urethane Grout the vibration in the process of the skycar caused the damage to the concrete surface of the oxen, and the concrete surface deposited a lot of steel dust. To clean up the ash, remove the old track and rinse with pressure water. Then use the axe to chisel the damaged concrete surface and the undamaged concrete layer, brush twice with the steel wire, and then clean the surface with clean water.
Rinse the CGM pulp with clean water, keep the concrete layer moist and clear the water. For the CGM to bond with concrete surface layer, the surface brush 302 interface agent. Interface agent ratio for the first division 1, 3 b, quartz powder five copies, mixed evenly mix into a milky white liquid, brush with brush evenly on the surface, side brush edges of CGM paste mixing is poured on the concrete pavement, dao compacted iron float shall be used. The interface agent should not be more than 2h after the surface of the concrete, so as to avoid the loss of the interface agent.
Two orbit of casting Urethane Grout 25 m 3, the highest temperature during the construction of 3 ℃. CGM pulp mixed with water is prepared by weight ratio 1:0.13, stirring time 3min, and the flow degree is 250mm. Due to the high temperature, the CGM slurry hydration heat is larger, and the curing time is controlled in 4h. Use sprinkler maintenance to reduce hydration heat, make CGM fully hydrate and prevent quality accidents due to dehydration. After 24h, it is covered with wet straw bag and can be used after curing 5 ~ 6h.
After 1d maintenance, Urethane Grout the project is put into use immediately. The compressive strength of 1d was 64.0 MPa, and the compressive strength was 11.0 MPa. The compressive strength of 28d is 89MPa, and the folding strength is 12.4 MPa, which meets the engineering requirements. After 2 years, return visit owner, reflect good.