Cusum Charts for the Control of the Slump Flow of Self-Compacting Concrete in a Steady Production Process
Author(s): Wolfram Schmidt, Hans-Carsten Kühne
Paper category: Conference
Book Title: 8th International RILEM Symposium on Self-Compacting Concrete - SCC 2016
Editor: Kamal H. Khayat
Publisher: RILEM Publications SARL
Publication year: 2016
Total Pages: 12
Abstract: Control chart systems are commonly used in quality management systems to keep production processes stable. The most efficient control chart systems are cumulated sums (cusum), which look at the deviations from a target value. Cusum charts react more rapidly on systematic changes in processes than other charts such as Shewhart charts, which look at the process values. The cusum method is often applied for compressive strength but it is particularly suitable if counteractions be taken immediately, like in the case of fresh concrete properties.
The present study shows that regardless of the manipulation, a steady slump flow can be achieved only by adding supplementary superplasticizer in case of loss of flow and adding stabilising agent (ST) in case of increased flow if the V-mask indicates a systematic change. A reference SCC was artificially manipulated in order to achieve either increased or reduced flowability. Arithmetic mean values and standard deviations were determined experimentally without and after taking counteractions. These parameters were used for case studies of steady SCC productions based on normally distributed random values. For the indication of a systematic change, a standard V-mask was used.
The results point out that productions with applied cusum methods were capable of keeping the slump flow deviation from the target in the order of magnitude of about 1% despite drastic manipulations, while productions without applied cusum method deviated up to 14% and more from the target slump flow value.
Online publication: 2016
Publication Type: full_text
Public price (Euros): 0.00
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