LONDON (Reuters) - U.S. cement maker Summit Materials <SUM.N> has made a $3.8 billion offer for rival Ash Grove Cement <ASHG.PK>, a source familiar with the matter told Reuters, hoping to trump an earlier takeover bid from Irish building materials firm CRH Plc <CRH.I>.


Ash Grove said earlier on Friday that it had received a new bid from an unnamed party which valued the business at $3.7-$3.8 billion.


The source said Summit Materials' bid was submitted on Thursday and is currently being considered by Ash Grove's board.


It could be the start of a bidding war with CRH, which last month agreed to buy Ash Grove for a total consideration of $3.5 billion.


(Reporting By Pamela Barbaglia; Editing by Rachel Armstrong)