Abstract:
This study aims to compare cast in situ concrete and precast concrete house building projects in terms of planning and management in Kigali, capital city of Rwanda. The city has recently experienced rapid urbanization due to migration of people from rural regions of the country. Nowadays population is approximately estimated to 1,288,000 people in 2024. There is need for more infrastructures in this city. Most of them are houses some with storeys which need concrete technology for sustainable structures. Both cast in situ and precast concrete technologies are found in the city, but mostly cast in situ is observed in many construction projects. This study compares in-situ concrete and precast concrete structures from the initial design phase up to the construction planning phase. The estimated construction time comparison estimated 180 days for cast in situ and 145 days for precast concrete. From previous researches, precast projects are mostly about $10,000 more costly than cast in situ projects. This can be the factor influencing adaption of cast in situ rather than precast concrete in Kigali city. The compressive strength of precast and cast in situ concrete were found to be 35 MPa and 30 MPa respectively. The defect rate for precast and cast in situ concrete were also found to be 2% and 5% respectively. The waste generation and CO2 emissions from production phase were higher for cast in situ concrete projects. The findings of this study aim to promoting a more effective and sustainable approach to concrete projects planning and management
