A comparative study on the carbon dioxide emissions of ready-mix concrete and precast concrete construction

The construction industry is one of the highest producers of greenhouse gases that cause global warming. Carbon dioxide (CO2) is the primary greenhouse gas. The aim of the study is to compare the environmental impact of concreting methods by analyzing the CO2, emissions during manufacturing, transportation, and casting/installation of concrete. The construction methods compared were ready-mix concrete (RMC) and precast concrete construction(PCC). The group located active concrete plants and ongoing high-rise construction projects for each method. Observation and inspection on-site were conducted in order to obtain actual processes and to determine the parameters needed, such as volume of concrete produced, duration of each activity, and the specifications of each machine. Lastly , the group utilized GREET.net and a research-based method in order to quantify CO2 emission in kilograms per volume of concrete produced per process. For the result of the RMC construction, the total average of CO2 emission is 18.578 kg-CO2/m3 and 17.287 kg-CO2/m3 for GREET.net and research-based method respectively. The percent difference is around 7.2%. In PCC construction, the total average of GREET.net and research based method were 17.437 kg-CO2/m3 and 17.542 kg-CO2/M3 respectively with a 0.6% percent difference. Averaging the results in all three plants, for both estimation methods, it was RMC that emits lesser amount of CO2, emission