Estimating the in-use cement stock in China: 1920-2013

- Chinese in-use cement stock in different branches from 1920 to 2013 is estimated.
- The outflow and age distribution of the in-use cement stock are calculated.
- Uncertainties in the in-use cement stock are evaluated by Monte Carlo simulation and sensitivity analysis.

Cement provides a foundational function for buildings and infrastructures in the modern society. Huge amounts of cement have been consumed during the rapid urbanization process in China. Understanding the trajectory of the in-use cement stock could gain insight into the cement inflow, waste flow and associated environmental impacts. However, an economy-wide estimation for Chinese in-use cement stock is still lacking. Using the dynamic MFA, this paper seeks to provide a long-period (1920-2013) estimate for Chinese in-use cement stock in three branches (i.e., buildings, infrastructure facilities and agriculture facilities). To evaluate uncertainties inherent in the in-use cement stock, the Monte Carlo method is adopted here to calculate the confidence intervals of the results. The simulation results demonstrate that, at the end of 2013, Chinese in-use cement stock has reached 21.5 billion metric tons whilst in-use cement stocks of the building, infrastructure and agriculture sector are 17.3, 3.4 and 0.8 billion metric tons, respectively. During the recent decade, the per capita in-use cement has been experiencing a sharp increase from 2.1t/capita in 1992-15.8t/capita in 2013. The exponential growth of Chinese in-use cement stock underlines the need for prolonging the lifetime and reducing cement intensity of buildings and infrastructures to realize dematerialization in China. The estimation on the historical evolution of the in-use cement stock could lay a solid foundation for predicting the future cement demand and related environmental impacts. In addition, robustness of the estimation method has been validated by the uncertainty and sensitivity analysis.