Hello Aspirant

The basic difference between M.Tech in Construction Management and PGDM or MBA in the same is that M.Tech course is more focussed on the technical aspects whereas PGDM or MBA in Construction Management is more focussed on the management side.
Though about 50% of both the courses are similar.

M.Tech in Construction Management has subjects like Quantity Surveying, Project Management Systems and Techniques, Contracts Management, Equipment Management, Quality Management, Material Management, Estimation, Health and Safety Management, Operations Management.

While PGDM in Construction Management has subjects like Accounting, Construction Economics, Real Estate Marketing, Project Marketing, Business Development, Human Resource Management, Strategic Management, Property Management, Asset Management, Finance.

Hope it helps :)