Bearing mortar

Bearing mortar

Bearing grouting material is a high-quality and high-performance modified cement-based grouting material. Due to the use of a variety of high-performance additives, the product has good construction performance, can be self-leveling, can operate for a long time, and the surface is smooth and flat after completion. It overcomes the shortcomings of traditional mortar such as unevenness, easy cracking, peeling and powdering. It has the characteristics of early strength and high strength, no shrinkage, micro expansion, good durability, and effective bearing area greater than 95%. It is specially developed for the gravity grouting of simply supported box girder basin rubber bearings on passenger dedicated lines, and its performance fully meets the requirements of "Temporary Technical Conditions for Bridge Basin Rubber Bearings on Passenger Dedicated Lines".

1. Product features

·Early strength and high strength: It has a very high hourly strength, which can reach a compressive strength of more than 20MPa in 2 to 4 hours. It has a high flexural strength. The 28-day compressive strength is ≥70MPa, and the later strength is high without shrinkage.

·High fluidity: A great fluidity can be achieved by just adding water and stirring on site, and all the gaps can be filled without vibrating.

·Micro-expansion: The stable period of expansion value is short, to ensure that the grouting material is in close contact with the grouting part to ensure no shrinkage.

·Good workability: not only good flow but also long holding time, with good cohesion, no layering and segregation, no bleeding.

·Low-temperature construction: The strength still increases greatly under low temperature, which effectively solves the problems of winter construction and other issues.

·Good durability: 2 million times of fatigue test, 50 times of freeze-thaw cycle test, no obvious change in strength; good performance of impermeability, frost resistance and corrosion resistance, and no corrosion of steel bars.

·It does not contain chloride and has no corrosive effect on equipment and steel bars.

·Easy to use: The finished product is dry-mixed mortar, which can be used after adding water as required on the construction site.

·The effective bearing area of ​​the upper surface of the bearing grouting material is greater than 95%.

2. Scope of application

·Suitable for special grouting for prefabricated simply supported box girder basin rubber bearings on passenger dedicated lines.

·Suitable for emergency repair, anchorage grouting of bridge support, track anchorage grouting, etc.

3. Main technical indicators

Four, use method

·Foundation treatment: the surface of the supporting cushion stone at the installation position of the burr bearing, remove the debris in the reserved holes, install the template for grouting, and the top surface of the template and the cushion stone should take reliable measures to prevent grout leakage during gravity grouting. The base layer to be grouted should be cleaned of dust, oil stains and other dirt that are not conducive to bonding. The base layer should be moistened with clean water to saturation, but no clear water should be left during construction.

·Lift the prefabricated box girder (with support), place the box girder on the temporary supporting jack, and adjust the elevation of the beam body fulcrum through the jack.

·After the beam is in place, a gap of 20 to 30mm should be reserved between the support bottom plate and the supporting pads of the pier and platform to facilitate the use of gravity grouting to inject the GTZ-YJ support grouting material.

·Using gravity grouting method to infuse the gap at the bottom of the support and the anchor hole. The grouting process should be grouted from the center of the support to the surroundings, until the grouting material is completely filled from the gap between the template and the base of the support. Before grouting, the required slurry volume should be preliminarily measured, and the actual amount of slurry poured should not be too large error with the calculated value to prevent lack of slurry.

·Slurries are prepared according to powder: water=1: (0.13 ~ 0.15) (weight ratio). The water should be added to the mixing barrel first, and then gradually added the weighed grout. While feeding, use an electric mixing gun to stir until all the powder is added, and then continue to stir for 2 to 3 minutes to make the slurry uniform.

·After the grouting material reaches the specified strength, remove the template, check whether there is grout leakage, and refill the leaking place.

·Tighten the foot bolts of the lower support plate, remove the connecting angle steel of the upper and lower support, remove the temporary jack, and install the support steel enclosure.

5. Material consumption

2100 ～ 2200 kg/m3