On-site monitoring of concrete laser screed flooring
1 The laser screed machine seamless construction pouring body monitoring points should truly reflect the highest temperature rise, the inner surface temperature difference, and the cooling rate. The monitoring points should be set up in accordance with the following regulations:
a When the minimum size of the ground structure entity is greater than 500mm, or when the temperature crack and shrinkage crack control requirements are strict, on-site monitoring should be carried out;
b The location and quantity of monitoring points should be based on the temperature field distribution and temperature control requirements of the cast unit
c The monitoring point should be the test area with the half axis of the long axis of symmetry axis of the cast unit plan, and the monitoring points in the test area should be evenly arranged according to the plane;
d On the test axis, the monitoring position of the central area in the thickness direction should not be less than 3 places.
The temperature measurement point around the section should be placed at a distance of 20mm~40mm from the surface of the structure, and the distance along the length should not exceed 10m;
e ambient temperature measurement point setting should not be less than 1 point, and should leave the structure of the pouring
2 The temperature difference, cooling rate and ambient temperature test in the concrete pouring body should meet the following requirements:
a should determine the modulo temperature of the concrete at each measuring point according to the temperature at which each temperature measuring point is first covered by the concrete;
b The internal temperature, surface and environment temperature measurement should be carried out simultaneously with the pouring and maintenance;
c should provide timely temperature measurement report according to the temperature measurement frequency requirements, including temperature measurement point temperature, temperature change curve, temperature change trend analysis, etc.
When the difference between the center temperature of the concrete structure and the ambient temperature is less than 201:, the temperature measurement can be stopped.
3 The temperature measurement frequency of the cast-in-place body should be dense in the early stage and should meet the following requirements:
a Measurement of mold temperature, no less than 2 times per shift;
b Within 1d~3d after concrete pouring, it should not be less than 1 every 4h; within 40d~7d, it should not be less than 1 every 8h; 7d to the end of temperature measurement, should not be less than 1 every 12h;
c During the sudden temperature change, the number of temperature measurements should be increased.
d The installation and protection of temperature measuring components shall comply with the following provisions:
a The joint installation position should be accurate, fixed firmly, and should be insulated from the metal body of the steel bar and the fixed frame;
b The lead wires should be arranged and properly protected;
c Concrete pouring with a laser screed shall not directly impact the test components and lead wires, and the vibrator shall not touch the test components and the lead wires.
5 When testing, it is advisable to describe the temperature change curve and the section temperature distribution curve of the monitoring point in time. When the monitoring value is abnormal, it should be alarmed in time and take corresponding measures.