Three Key Considerations for Additive Usage in Concrete Production
Additives play a crucial role in concrete production, but it is essential to pay special attention to the following aspects to ensure concrete quality and engineering safety.
I Uniform Feeding is Essential
Additives aqueous solutions are typically stored in tanks, with a tendency for solid particles to settle, resulting in higher concentrations at the bottom and lower concentrations at the top. During production, it is crucial to avoid drawing additives from either the very bottom or the top to ensure uniformity. When conducting trials, it is advisable to thoroughly mix the sample container by shaking it before measurement to enhance testing accuracy.
II Accurate Measurement
Although the quantity of Additives added is relatively small, their impact on concrete performance is significant. Inaccurate measurement of additives can lead to inconsistent concrete performance and even cause severe engineering quality issues. For instance, if the dosage of wood calcium exceeds 0.5% of the cement mass, it may introduce excessive air, delaying initial setting time and reducing early concrete strength. Similar situations apply to sugar solutions and humic acid-based water-reducing agents, which may result in concrete that remains unset and unhardened for several days.
III Compensating for Slump Loss
When concrete mixtures experience a substantial slump loss due to factors such as long transportation or waiting time at the construction site, and pumping becomes difficult or impossible, adding water arbitrarily is not recommended. Instead, a compensating measure involving the addition of a water-reducing agent should be employed. This entails adding a pumping agent (water-reducing agent) equivalent to the original mix ratio and then subjecting the mixture to high-speed agitation in the mixing drum for 2 minutes to ensure thorough and uniform mixing before discharging. This procedure must be strictly controlled and ideally supervised by technical personnel on-site. This ensures that the correct compensatory measures are taken in the event of slump loss, maintaining the quality of concrete and ensuring engineering safety.
