# Calculation Methods for Construction Material Stocks: A Systematic Review
## 3 Results
### Content Analysis
#### 3.2.2 Material Stock Calculation Methods
The study used the top-down methodology by reviewing the previous research to find the total building area constructed. Afterward, material stock for the whole country of Japan was estimated using the average material intensity. The result showed that cement, aggregate, and asphalt were the major stocked material and comprised 95% of stocked materials. Overall, the study found that the material stock had increased from 3.1 billion tons to 16.5 billion tons between 1965 and 2010. In another study, [PERSON] and [PERSON] [31] investigated the material stock disparity in 31 provinces of China. The study estimated the stock of ten types of material stored in residential buildings, roads, railways, and water pipes between 1978 and 2008. The results showed that the total material stock increased to 42.5 billion in 2008, with per capita material stock increasing nine times. It was also shown that the material stock had spatially decreased from the coastline to inland areas. This paper also found that the top-down method has also been applied for the calculation of material stock at the regional scale. The use of this method at the regional level requires the material intensity to be more detailed compared to the country-level application. [PERSON] et al. [41] analyzed the flow of materials at use phase, construction, and demolition waste of the residential buildings in the city of Rio de Janerio in Brazil. They applied a top-down methodology to estimate the material stock by using the material intensities of different types of buildings constructed during different times of the year. The results suggested that the material stock of residential buildings in 2010 was 78,828,770 tons, with the material intensity between 2.58-0.74 t/m\({}^{2}\). [PERSON] et al. [35] also quantified the material stock of nondomestic buildings in Germany. The study categorized the non-residential buildings into different types and calculated the average material intensity for each building type. The study estimated the total material stock by combining the average floor area for each building type and material intensity. The results showed that the total material stock of non-residential buildings in Germany was 6.8 billion tons constituting 44% of the entire building stock. Likewise, [PERSON] et al. [42] quantified the material stock of non-residential buildings in the Rhine-Main area in Germany. The study categorized the non-residential buildings into different types of use and age constructed, using the average material intensity found the total material stock using GIS. The results showed that the total material stock of non-residential buildings was approximately 65 million m\({}^{3}\). Using the top-down methodology, [PERSON] et al. [40] estimated the Polychlorinated biphenyls (PCBs) used in residential and non-residential buildings in Norway between the 1950s and 1980s. The PCBs can be deleterious to the environment once released and they can bioaccumulate in human and animal tissue [40]. The total amount of toxic plastic was estimated by combining the material intensity with the building's total material stock. The results indicated that PCBs peaked around the 1980s then decreased as the government banned the application of PCBs. It was discovered that the PCBs presence was 156.2 and 231 tonnes in residential non-residential buildings, respectively. In another study, [PERSON] et al. [18] calculated the loss of material stock in Japanese buildings and roads due to the 9.0 earthquake and tsunami that struck eastern Japan in 2011. The study was conducted by reviewing the images of damaged buildings and the average material intensity from the literature. The total material stock lost was calculated by comparing the images before and after the tsunami and analyzing them using GIS. Results showed that the total material stock losses of buildings and roads were 31.8 and 2.1 million tonnes, respectively. Further, this paper realized that GIS had been employed to estimate the material stock using the top-down method.