Quality can be defined as conformance with requirements, freedom from defects or contamination, or simply the degree of customer satisfaction.
Quality assurance is an all encompassing term, which includes quality control, and refers to all the planned and systematic actions necessary to provide confidence that a product will perform satisfactorily in service. Factory Production Control and laying procedures for paving materials outline such actions.
Milestone provides independent assurance by acting as a third party, not directly responsible for process control or acceptance, to assess conformance with requirements.
This may involve system audits and/or site monitoring.