Document Type
Extended Abstract
Abstract
Cold weather concreting (CWC) generally refers to practices used to place concrete during cold weather. Traditionally, concrete placement in cold weather is accomplished by one or more precautions and procedures, such as pre-heating water and/or aggregates, insulating the concrete with protective blankets during curing, or heating the concrete or the surrounding concrete. However, these procedures can be energy-intensive, resulting in a shortened construction season in cold regions. Additive-based freeze protection (ABFP) is an alternative approach to casting and curing concrete at cold temperatures that reduces energy costs compared to traditional CWC techniques and potentially extends the construction season. Cold-weather self-consolidating concrete (CWSCC) is highly flowable without segregation and can be cast and cured at freezing temperatures, particularly at -5 °C. The adverse effects of freezing temperatures on the properties of CWSCC are mitigated by incorporating an ABFP system using an accelerator and a corrosion inhibitor. The ABFP system shall decrease the freezing point of CWSCC and hasten the hydration process. Three types of cementitious materials are considered: portland cement (PC) only, PC with granulated ground blast furnace slag, and PC with fly ash. Four building sizes and four heating sources are considered: diesel, electricity, propane, and natural gas. The average cost of CWSCC is 37% and 30% lower compared to vibrated concrete (VC) and conventionally heated self-consolidating concrete (SCC), respectively. The embodied CO2 in CWSCC is also lower than cold-weather vibrated concrete and SCC. The average CO2 in CWSCC is 3% and 8% lower compared to cold weather VC and SCC.
Keywords
Cold-Weather, Self-Consolidating Concrete, Carbon.
DOI
10.5703/1288284318044
Impact of Additive-Based Frost Protection on CO2, Cost, and Rheology on Cold-Weather Self-Consolidating Concrete
Cold weather concreting (CWC) generally refers to practices used to place concrete during cold weather. Traditionally, concrete placement in cold weather is accomplished by one or more precautions and procedures, such as pre-heating water and/or aggregates, insulating the concrete with protective blankets during curing, or heating the concrete or the surrounding concrete. However, these procedures can be energy-intensive, resulting in a shortened construction season in cold regions. Additive-based freeze protection (ABFP) is an alternative approach to casting and curing concrete at cold temperatures that reduces energy costs compared to traditional CWC techniques and potentially extends the construction season. Cold-weather self-consolidating concrete (CWSCC) is highly flowable without segregation and can be cast and cured at freezing temperatures, particularly at -5 °C. The adverse effects of freezing temperatures on the properties of CWSCC are mitigated by incorporating an ABFP system using an accelerator and a corrosion inhibitor. The ABFP system shall decrease the freezing point of CWSCC and hasten the hydration process. Three types of cementitious materials are considered: portland cement (PC) only, PC with granulated ground blast furnace slag, and PC with fly ash. Four building sizes and four heating sources are considered: diesel, electricity, propane, and natural gas. The average cost of CWSCC is 37% and 30% lower compared to vibrated concrete (VC) and conventionally heated self-consolidating concrete (SCC), respectively. The embodied CO2 in CWSCC is also lower than cold-weather vibrated concrete and SCC. The average CO2 in CWSCC is 3% and 8% lower compared to cold weather VC and SCC.