Inquiry Regarding Substitution of Grout with HIT-RE 500 Injection Mortar for Pedestrian Bridge Bearing Details

Dear HILTI Support Team,
I hope this message finds you well. I am currently working on a pedestrian bridge project where we have specified the use of a maximum of 30mm grout below the bottom attachment plate. However, the contractor has suggested substituting the specified grout with HIT-RE 500 injection mortar for this application.
I am reaching out to inquire about the suitability and compliance of using HIT-RE 500 injection mortar as a substitute for the specified grout in this scenario. Could you kindly provide information or guidance regarding the feasibility, performance, and compliance of HIT-RE 500 injection mortar for this particular use in a pedestrian bridge bearing application?
Additionally, if there are any technical specifications, guidelines, or recommendations from HILTI regarding the use of HIT-RE 500 injection mortar in such structural scenarios, I would greatly appreciate receiving them for further review and consideration.
Thank you very much for your attention to this matter. Your guidance and expertise in this regard would be invaluable to ensure the structural integrity and safety of our pedestrian bridge project.
Best regards,
Amr