Utilization of Six Sigma in Quality Improvement of Recycled Aggregates Concrete

Table 1

Independent variables affecting the strength of RAC.

Quality	Proportions	Mixing	Testing
Age of demolished construction	w/c ratio	Environmental temperature	Curing
Chloride and sulfate content of RA	% of coarse RA	Mixing tools	Sample size
% of impurities in RA	% of fine RA	Mixing method	Testing tools and machines
Quality of RA	Cement content	Operators	Operators
Type of RA	Cement type	Water saturation condition of RA	Age at testing
	Additives
	Admixtures or agents
	Size of RA
	Aspect ratio of RA