Establish concrete placing rates using quality control records from Hong Kong building construction projects

This paper focuses on the topic of data collection as appropriate for the productivity study of ready mixed concrete placing methods. Classification and description of various concrete placing methods are given. The normally available quality control (QC) records for 462 concrete pours from five ongoing Hong Kong building construction projects were captured into a database, representing a total of 6,833 truckmixer trips out of two major concrete plants in Hong Kong. By querying the database, the placing rates for particular placing methods were established, and validated by comparison with existing industry benchmarks. One promising observation is that in general the Hong Kong construction sites may now be more efficient in processing truckmixers than they were a decade ago. The normal concreting QC records, routinely accumulated on site in a mandatory and standardized fashion, include the timing and quantity data as needed because of the time-sensitive nature of freshly mixed concrete. Data of this type is a better and more convenient alternative to collection by direct observation and measurement. The concreting placing rates for the various placing methods derived from the database are found to be potentially of direct value for assisting concrete plant and site managers in estimating the progress of work and attaining better coordination in concrete supply and placing between concrete suppliers and site contractors. They also serve as performance yardsticks for benchmarking the state of the Hong Kong concreting industry as time goes by and indeed, and most usefully, for comparison with other large cities if similar records are obtained for processing from those cities.