If client reject the concurrent delay claim, what reason he can give. If he approve then will time and cost will be reimbursed.?

Concurrent delays can easily be defined as simultaneous delays caused by the general contractor and the project owner, affecting the project schedule and project completion date. Some others have defined it as "Two or more delay events occurring within the same time period,each independently affecting the Completion Date"  and in many instances, your business can be entitled to be compensated to cover extra costs or damages following these type of delays.

If your client reject the concurrent delay claim, he can ground his decision on lack of notice of delay from the contractor, informal notices of claim as stated in the contract and so.

When the client approved the claim and the delay was caused by the client, the contractor may be able to claim an extension of time and loss and expense.

first of all the contractor shall prove by documents that the delay is not his responsibility and that can be achevied by (contract documents and the contractor submittals backed by time schedules documents) and those are the bases used by the client to prove that the delay is the contractor responsibility.

if the client fails to prove that the delay is the contractor responsibilty then the contractor calim is deemed to be valid and the client is forced by the contract documents to give extension of time and financial compensation for the contractor losses which is determined by the supervision engineer and approved by client representative on site.

if the client didnt comply to the claim submitted by the contractor then an engineering arbitrator shall be assigned for conflict resolution prosess to verify the contractor claim and his discesion will be submitted to the clients representative on site.

suppose this proscess is completed and the client didn't comply to the claim then the  whole documnets shall be sent to court of law as a juricedection area for conflict resolution 

The client needs no reimbursement.

The claim of delay must be well sustained. If approved, he shall pay the time and cost