Sheheryar Mubashar, Rehan Rashid, Nehdi Moncef L
National Institute of Urban Infrastructure Planning, University of Engineering and Technology, Peshawar 25000, Pakistan.
Department of Civil and Environmental Engineering, University of Western Ontario, London, ON N6A 5B9, Canada.
Materials (Basel). 2021 Feb 20;14(4):995. doi: 10.3390/ma14040995.
Ordinary Portland cement concrete (OPC) is the world's most consumed commodity after water. However, the production of cement is a major contributor to global anthropogenic CO emissions. In recent years, ultrahigh performance concrete (UHPC) has emerged as a strong contender to replace OPC in diverse applications. UHPC has much higher mechanical strength, and thus less material is used in a structural member to resist the same load. Moreover, it has a much longer service life, reducing the long-term need for repair and replacement of aging civil infrastructure. Thus, UHPC can enhance the sustainability of cement and concrete. However, there is currently no robust tool to estimate the sustainability benefits of UHPC. This task is challenging considering that such benefits can only be captured over the long-term since variables, such as population growth and cement demand per capita, become more uncertain. In addition, the problem of CO emissions from cement and concrete is a complex system affected by time-dependent feedback. The System Dynamics (SD) method has specifically been developed for modeling such complex systems. Accordingly, a SD model was developed in this study to test various pertinent policy scenarios. It is shown that UHPC can reduce cumulative CO emissions of cement and concrete-over the studied simulation period-by more than 17%. If supplementary cementitious materials are further deployed in UHPC and new technologies permit reducing the carbon footprint per unit mass of cement, emission savings can become more substantial. The model offers a flexible framework where the user controls various inputs and can extend the model to account for new data, without the need for reconstruction of the entire model.
普通硅酸盐水泥混凝土（OPC）是仅次于水的全球消耗量最大的商品。然而，水泥生产是全球人为碳排放的主要贡献者。近年来，超高性能混凝土（UHPC）已成为在各种应用中替代OPC的有力竞争者。UHPC具有更高的机械强度，因此在结构构件中使用更少的材料就能承受相同的荷载。此外，它的使用寿命长得多，减少了对老化民用基础设施进行长期维修和更换的需求。因此，UHPC可以提高水泥和混凝土的可持续性。然而，目前还没有可靠的工具来评估UHPC的可持续性效益。考虑到这些效益只能在长期内体现，因为诸如人口增长和人均水泥需求等变量变得更加不确定，所以这项任务具有挑战性。此外，水泥和混凝土的碳排放问题是一个受时间依赖性反馈影响的复杂系统。系统动力学（SD）方法专门用于对这种复杂系统进行建模。因此，本研究开发了一个SD模型来测试各种相关政策情景。结果表明，在研究的模拟期内，UHPC可以使水泥和混凝土的累计碳排放量减少超过17%。如果在UHPC中进一步使用辅助胶凝材料，并且新技术能够降低单位质量水泥的碳足迹，那么减排效果会更加显著。该模型提供了一个灵活的框架，用户可以控制各种输入，并可以扩展模型以纳入新数据，而无需重建整个模型。
