1, grouting material selection
One end of the grouting connection of assembled building steel sleeve is threaded, and the other end is provided with multiple semi-grouting joints. Filling grouting material is based on cement, with appropriate fine aggregate, admixture and other materials. After mixing with water, it should have good fluidity, early strength, high strength and slight expansion. Grouting materials selected for grouting connection of reinforcing steel sleeve should match the performance of reinforcing steel sleeve, and the inspection of the extracted centering connection joint should meet the requirements of Class I joint in Technical Specification for Mechanical Connection of Reinforcement (JJ107-2016). The indexes of grouting materials shall meet the requirements of JG/T 408-2013 Sleeve Grouting Materials for Reinforcement Connection and GB/T 50448-2015 Technical Specification for Application of Cement-based Grouting Materials.
2. Storage of grouting materials
Grouting materials should have product certificate, ex-factory inspection report and re-inspection report when they enter the site, and can only be used in the project if they are qualified. The storage period of grouting materials is 3 months, and a special storage warehouse should be set up, which should be moisture-proof, rain-proof, sun-proof and ventilated. The warehouse shall be equipped with a storage rack for grouting materials (not less than 200m from the ground). Mm), so that grouting materials can be stacked in a cool and dry place. Check the storage date of grouting materials at any time, and use advanced materials first. Grouting materials that have passed the storage period shall be tested to determine whether they can be reused.
3. Mixed grouting materials
(1) Preparation of grouting materials and machines: grouting materials and clear water; Agitator, air compressor, slurry storage tank, balance, thermometer, bucket, cone mold for liquidity detection and glass plate, steel ruler or tape measure, etc. , should be equipped with corresponding emergency generator, in order to prevent sudden power failure during grouting.
(2) Preparation of grouting material: When opening the packing bag of grouting material, check the appearance of the product. After the powder and aggregate are mixed evenly and do not agglomerate due to moisture or other abnormalities, they should be weighed as required and stored in barrels or bags. Store the mixed water in a water container, weigh it according to the corresponding mixture ratio, then pour the grouting material into the blender, start the blender, slowly add water, and mix evenly for 7-8? Min, let it stand for 2~3? Minimize the elimination of bubbles.
5. Preventive measures
(1) The contact surface between precast wall and concrete shall be free of dust, oil stain and sundries. Before hoisting the prefabricated wall, insert the thin steel wire into the casing from the upper grouting hole. If you can extend from the bottom and see the steel wire from the lower grouting hole, it will be clear; If the thin steel wire can't extend from the bottom, it means that there are sundries in the casing, which need to be removed until it is unobstructed.
(2) Wet the grouting hole with water before grouting, so as to reduce the phenomenon that the grouting strength can not meet the requirements and the connection with the grouting hole is unreliable due to the water absorption of concrete.
(3) Insulating materials such as wall bottom shall be laid at the overflow hole to prevent mud overflow from polluting the ground. After the grouting operation is completed, the residual slurry on the wall and ground shall be cleaned in time. Grouting parts should be watered, and the water content should not be lower than 7? d .
(4) Immediately after grouting, clean the grouting machine and mixing equipment with clear water. 24? H Do not apply any vibration or impact to the wallboard. H rear can arrange to dismantle the temporary inclined support of precast concrete wall, and then use it for recycling.
(5) Grouting of assembled building steel sleeve can be carried out in 5~ 10? For working in the environment of℃, it is not suitable to work in hot weather, winter and rainy days, otherwise corresponding measures should be taken to cool down, keep warm and prevent rain.
Grouting construction process of steel sleeve is the key link of quality control of assembly building installation and construction, and also the key point of engineering quality control. As long as the construction unit manages scientifically, operates meticulously, puts the responsibility on people, links with each other, and strictly controls, it can provide a strong guarantee for the construction quality of prefabricated buildings and ensure that the project quality will last for a hundred years.