Section 29C. Any provision for or in connection with a contract for construction, reconstruction, installation, alteration, remodeling, repair, demolition or maintenance work, including without limitation, excavation, backfilling or grading, on any building or structure, whether underground or above ground, or on any real property, including without limitation any road, bridge, tunnel, sewer, water or other utility line, which requires a subcontractor to indemnify any party for injury to persons or damage to property not caused by the subcontractor or its employees, agents or subcontractors, shall be void.