Optimal Construction Site Conditions for Concrete Operations

摘要

Concrete usually undergoes stringent quality controls during its fabrication in a batching plant or when made in situ. However, there are several conditions in the construction site that may affect concrete quality and operations. Reduction in compressive strength, increment in costs of concrete fabrication and low productivity are among the consequences of adverse jobsite conditions. In this study, construction site conditions including crew experience, compaction method, mixing time, curing humidity, and curing temperature were selected as variables to conduct a full 25 factorial experimental design for quantifying their effect on concrete. Cylindrical concrete samples were fabricated and evaluated under each factor combination. Concrete compressive strength as a quality metric, costs, and production rates were measured as the experimental responses. Significant affecting factors and their effects on concrete were identified through the analysis of variance (ANOVA) and used to predict concrete compressive strength, cost, and production effects. A multi-objective optimization problem based on compromised solutions was formulated to maximize both concrete quality and production rates, and to minimize operation costs. The results show that high curing humidity and temperature have a positive effect on compressive strength while high mixing times increases concrete cost and reduces productivity. The proposed optimization model provides construction managers with a tool that allows finding in-situ construction conditions to reach desired goals. Further, understanding the possible impacts of these site conditions on concrete allows taking preventive actions.