Applying materials waste quantification to cement waste reduction in residential buildings of Tehran: A case study

Purpose of this research is twofold. Study’s first part focuses on developing quantitative wastage models for rebar, concrete, brick and cement, as major bulk traditional building materials, used in Tehran residential buildings. Primary results indicate that multiple linear regression is an apt tool to model studied variables’ effects on materials wastage. In every developed wastage model, subtractive or accumulative effect of each studied variable is recognized by its coefficient value and sign. Developed models resulted in adjusted R2 values of 0.907, 0.875, 0.920 and 0.790 respectively for rebar, cement, brick and concrete waste. Cement, with average wastage of 8.57% by weight, is identified as the most wasted material verified by the case study. In study’s second part, previously developed models as well as project management experts’ opinions were combined to structure a cement waste reduction guideline for traditional building construction which is common in Tehran, Iran. With this purpose in mind, for projects’ initiating phase, choosing lump-sum contract instead of cost-plus contract is suggested. Moreover a financial incentive reward scheme, with its economic viability and environment friendliness, has been tested with positive results and hence is proposed for construction phase. Applicability of proposed scheme is verified through a case study.