Exhibit 3.31(a)

State of Delaware Secretary of State Division of Corporations )elivered 10:44 AM 09/29/2009 FILED 10:31 AM 09/29/2009 RV 090892203 — 4736003 FILE STATE of DELAWARE LIMITED LIABILITY COMPANY CERTIFICATE of FORMATION First: The name of the limited liability company is ____________________ Concrete Acquisition LI1 LLC Second: The address of its registered office in the State of De1warc is ___________ 615 South Dupont Hwy n the City of Dover Zip code 199ffl The name of its Registered agent at such address is pjtut ScMces, Inc. Third: (Use this paragraph only lithe company Is to hove a specific effective date of dissolution; “The latest date on cvhich the limited liability company is to dissolve s __________________________ ‘I) Fourth: (Insert any other matters the members determine to ipolude herein.) hi Witness Whereof, thc undersigned have executed this Certificate of Formation this 29th day of September  , 2009 Authorized Person (s) Name:. StephDnie Colitni

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