Concrete: Refers to the general term for engineering composite materials in which aggregates are cemented into aggregates by cementitious materials. Generally, the term concrete refers to the use of cement as the cementitious material, sand and stone as the aggregate, and water (plus or minus). Admixtures and admixtures are blended with a certain proportion of man-made stone with certain strength through stirring, forming and curing, also known as ordinary concrete. It is widely used in civil engineering.
First, control of concrete production process
The work performance of concrete is one of the key conditions to ensure the quality of the project. We must do a good job of preparing the concrete before production. The implementation of any new formula must have one week of implementation of any new formula, and any new formula must be implemented for one month. Trial production methods, trial production formulas can only be used for minor projects, minor parts, and the one-month trial production period, trial production formulas can only be used for secondary projects, and secondary sites can be considered for degraded use. In addition during the trial production of concrete, the correction of measuring equipment, inspection of pounds, and the frequency of concrete sampling should be strengthened.
1, try mixing
Before the production, the laboratory must use on-site production of raw materials. According to the ratio of production, the concrete is mixed and the performance of all aspects of the concrete mixture is checked. For example, the concrete unit water consumption, workability, and condensation Time, gas content, etc.
(1) The dispatcher (dispatcher) must be responsible for organizing periodic inspections, maintenance and commissioning of the production equipment, checking and calibrating the measuring instruments, and making corresponding records to ensure the accuracy of the raw material materials measurement. in production. The production must be strictly carried out according to the mix ratio, strictly controlling the measurement deviation within the allowable range, in which the measurement deviation of cement, mixed materials, water and additives is ±2.0%, and the sandstone measurement deviation is ±3.0%. If the product is not manufactured according to the formula, misuse of formula, unauthorized modification of the formula or equipment, etc. cause the concrete quality to be unqualified and leave the factory and be returned by the construction site, the parties concerned and the supervisor in charge shall be held accountable.
(2) The mixer truck must be checked and tested for tolerances no less than twice a day. Abnormal conditions should be reported to the QC supervisor in a timely manner, and corresponding treatment should be made and related records should be made.
(3) Periodically check the electronic pounds for each raw material to ensure the accuracy of the measurement system. If errors are found during self-inspection, they must be recalibrated. The inspection results and time must be recorded for future reference. Severe abnormalities should be immediately discontinued during use, and be reported to the supervisory leader to arrange for related personnel to inspect the maintenance process. If necessary, contact the measurement unit agency to maintain the treatment. After the maintenance process is passed, the user can continue to use it.
(4) The pounds of admixture must be calibrated once a day with weights before starting production. Sand, stone, cement, slag, fly ash and other pounds are checked once a week.
3, production ingredients
(1) The batcher should prepare each tank in strict accordance with the production operating procedures, and mix the mixture into the mixer drum accurately and evenly. In the mixing process, the homogeneity of the mixed concrete mix shall comply with the provisions of GB50164-92.
(2) The shortest time for concrete mixing shall comply with the specifications of the equipment specification. According to the company’s mixing equipment, the mixing time per tank is not less than 20-30 seconds. For concrete with special requirements, it should be properly adjusted according to actual conditions.
(3) The moisture content of the aggregate should be determined during the production process, and each work class should not be less than once. In particular, if the rainwater content has a significant change on the day, the number of measurements should be increased, and the water consumption should be timely adjusted based on the test results. Aggregate usage, and control according to the production process of aggregate-containing aqueous concrete.
(4) In the production process, the QC must pay close attention to observing the concrete’s fluidity, water retention, cohesiveness, sand content, concrete air content, loss of concrete mixture over time, and concrete setting time.