Factors influencing power-trowelling productivity of concrete surface floors

Purpose: The purpose of this paper is to investigate the effects and relative influence of: surface floor area; number of trowelling machines used in the operation; machine floating ring diameter size; and operative employment mode, on power-trowelling productivity of concrete surface floors. Design/methodology/approach: To achieve this objective, a sufficiently large volume of productivity data was collected and analyzed using the categorical-regression method. As a result, the effects and relative influence of the factors investigated on trowelling productivity were determined and quantified. Findings: The findings show significant influence of the factors explored on the trowelling productivity of concrete surface floors, which substantiate the importance of the "economy of scale" concept, and confirm the negative effect of "overcrowding". On the other hand, contrary to many previous productivity research findings, and anecdotal perceptions of industry practitioners, the results obtained provide little evidence to the positive impact of the subcontracting employment mode on the trowelling operation. Research limitations/implications: Further research into the influence of other factors which could not be determined by this study, i.e. quantifying the difference in trowelling productivity between the "walk-behind" and "ride-on" machine types, and the average change in the operation efficiency as a result of utilizing the 0.60 m "walk-behind" floating ring diameter size, in comparison with the 0.80, 1.00, and 1.20 m explored ring-size, is recommended. On the other hand, the results obtained suggest that for a specific surface floor area, there may be an optimum number of trowelling machines, which leads to optimum trowelling productivity. It is, therefore, recommended to determine this number in order to rationalize the use of such devices and optimize the efficiency of the operation. Practical implications: The findings of this research can provide estimators, planners and construction managers guidance for reasonable estimates, effective planning and efficient operative utilization. The results obtained may be further used to "benchmark" the efficiency of the operation, and "formalize" the specific productivity knowledge acquired. Originality/value: The outcomes of this study fill a gap in productivity knowledge of primary factors influencing an important surface floor finish technique, which is frequently encountered on concrete construction sites, especially parking structures, storages and industrial facilities.