Exhibit
      4.3

    


     

    FIFTH
      AMENDMENT TO

    CREDIT
      AGREEMENT

     

    THIS
      FIFTH AMENDMENT (“Amendment”) dated as of August 6, 2008, by and between
      Superior Materials, LLC and BWB, LLC, each a Michigan limited liability company
      (“Companies”) and Comerica Bank (“Bank”).

    


    RECITALS:

    


    A.    Companies
      and Bank entered into a Credit Agreement dated as of April 6, 2007, as amended
      by four amendments (“Agreement”).

     

    B.    Companies
      and Bank desire to amend the Agreement as hereinafter set forth.

     

    NOW,
      THEREFORE, the parties agree as follows:

    


    1. The
      following definitions in Section 1 of the Agreement are amended to read as
      follows:

     

    “‘Applicable
      Fee Percentage’ shall mean, as of any date of determination thereof, one quarter
      of one percent (1/4%) per annum.

     

    ‘Applicable
      L/C Commission Rate’ shall mean as of any date of determination thereof, two and
      one quarter percent (2 1⁄4%) per annum.

     

    ‘Applicable
      Margin’ shall mean, as of any date of determination thereof, (a) for Prime-based
      Advances, two percent (2%) per annum and (b) for Eurodollar-based Advances,
      four
      and one quarter percent (4 1⁄4%) per annum.

     

    ‘Borrowing
      Base’ shall mean as of any date of determination, the sum of (a) eighty five
      percent (85%) of Eligible Accounts, plus (b) the lesser of (i) fifty percent
      (50%) (subject to Bank approval in its sole and absolute discretion, but in
      no
      case less than forty percent (40%)) of Eligible Inventory and (ii) $5,000,000,
      plus
      (c) the
      lesser of (i) fifty five percent (55%) of the orderly liquidation value of
      Company’s eligible machinery and equipment (as determined from time to time
      based on appraisals of such machinery and equipment from an appraiser acceptable
      to Bank) plus the Collateral L/C Amount and (ii) Six Million Dollars
      ($6,000,000); provided however, that the Borrowing Base shall be determined
      on
      the basis of the most current borrowing base certificate required to be
      submitted hereunder, provided, further, that the amount determined as the
      Borrowing Base shall be subject to any reserves for contras/offsets, potential
      offsets due to customer deposits, and such other reserves as reasonably
      established by Bank in the exercise of its reasonable credit judgment from
      time
      to time, including, without limitation any reserves or other adjustments
      established by Bank, in each case in the exercise of its reasonable credit
      judgment on the basis of any collateral audits conducted hereunder. In the
      event
      that Bank, at any time in the exercise of its reasonable credit judgment,
      determines that the dollar amount of Eligible Accounts collectable by a Company
      is reduced or diluted as a result of discounts or rebates granted by the
      applicable Company to the respective Account Debtor(s), returned or rejected
      Inventory or services, or such other reasons or factors as Bank deems applicable
      in the exercise of its reasonable credit judgment, Bank may, in the exercise
      of
      its reasonable credit judgment, upon five (5) business days’ prior written
      notice to Companies, reduce or otherwise modify the percentage of Eligible
      Accounts included within the Borrowing Base and/or reduce the dollar amount
      of
      Eligible Accounts by an amount determined by Bank in its reasonable credit
      judgment.”

     

    
      
         

      

      
         

        
          

        

      

      
         

      

    

     

    2.    The
      following definitions are added to Section 1 of the Agreement in alphabetical
      order to read as follows:

     

    “’Levy
      Credit Agreement’ shall mean the Credit Agreement dated as of September 29, 2006
      by and among Edw. C. Levy Co., as borrower, the lenders party thereto and
      Comerica Bank, as agent, as the same may be amended, modified or amended and
      restated from time to time or any Credit Agreement which replaces such Credit
      Agreement.

     

    ’Support
      Letters’ shall mean the support letters dated as of August __, 2008 by the
      Support Parties in favor of Bank, as the same may be amended or modified from
      time to time.

     

    ‘Support
      Parties’ shall mean Edw. C. Levy Co. and U.S. Concrete, Inc. and ‘Support Party’
shall mean each of them.”

     

    ‘U.S.
      Concrete Credit Agreement’ shall mean the Credit Agreement dated as of June 30,
      2006 by and among U.S. Concrete, Inc., as borrower, the lenders party thereto
      and Citicorp North America, Inc., as administrative agent, as the same may
      be
      amended, modified or amended and restated from time to time or any Credit
      Agreement which replaces such Credit Agreement.”

     

    3.    Sections
      2.1 and 2.6 of the Agreement are amended to change each reference to “Twenty
      Million Dollars ($20,000,000)” to read “Seventeen Million Five Hundred Thousand
      Dollars ($17,500,000)”.

     

    4.    Section
      4.8 of the Agreement is amended to read as follows:

     

    “[Reserved].”

     

    5.    Sections
      7.11, 7.12 and 7.13 of the Agreement are amended to read as
      follows:

     

    “7.11
      [Reserved].

     

    
      
         

      

      
         

        
          

        

      

      
         

      

    

     

    7.12
      [Reserved].

     

    7.13 Maintain
      as of the end of each fiscal quarter specified below, EBITDA of not less than
      the amount specified below:

     

    
      	
              Fiscal
                Quarter Ending

            	 	 	
              Amount

            	 
	
              September
                30, 2008

            	 	 	
              ($4,829,000

            	
              )

            
	
              December
                31, 2008

            	 	 	
              ($3,300,000

            	
              )

            
	
              March
                31, 2009

            	 	 	
              ($3,978,000

            	
              )

            
	
              June
                30, 2009

            	 	 	
              ($2,798,000

            	
              )

            
	
              September
                30, 2009

            	 	 	
              ($2,661,000

            	
              )

            
	
              December
                31, 2009

            	 	 	
              ($2,984,000

            	
              )

            
	
              March
                31, 2010 and thereafter

            	 	 	
              ($3,041,000)”

            	 


    

    


    6.    Schedule
      1.1 to the Agreement is deleted.

     

    7.    Sections
      10.2 (f) and (l) and Section 10.3 are amended to read as follows:

     

    
      	 	
              “(f)

            	
              default
                in the observance or performance of any of the conditions, covenants
                or
                agreements of Companies or any other Person set forth in any collateral
                document which may be given to secure or support the indebtedness
                hereunder or in any other collateral document related to or connected
                with
                this Agreement or the indebtedness hereunder and continuance for
                ten (10)
                days;

            


    

     

    
      	 	
              (l)

            	
              if
                any of the Guaranties is revoked or any Support Letter is
                revoked;

            


    

     

    10.3 If
      a
      creditors’ committee shall have been appointed for the business of any Company,
      any Subsidiary or any Guarantor in connection with any bankruptcy or insolvency;
      or if any Company, any Subsidiary or any Guarantor shall have made a general
      assignment for the benefit of creditors or shall have been adjudicated bankrupt,
      or shall have filed a voluntary petition in bankruptcy or for reorganization
      or
      to effect a plan or arrangement with creditors; or shall file an answer to
      a
      creditor’s petition or other petition filed against it, admitting the material
      allegations thereof for an adjudication in bankruptcy or for reorganization;
      or
      shall have applied for or permitted the appointment of a receiver, or trustee
      or
      custodian for any of its property or assets; or such receiver, trustee or
      custodian shall have been appointed for any of its property or assets (otherwise
      than upon application or consent of the applicable Company, any Subsidiary
      or
      any Guarantor, as applicable), and such receiver, trustee or custodian so
      appointed shall not have been discharged within sixty (60) days after the date
      of his appointment or if an order shall be entered and shall not be dismissed
      or
      stayed within sixty (60) days from its entry, approving any petition for
      reorganization of any Company, any Subsidiary or any Guarantor, then the Note
      and all Indebtedness then outstanding hereunder and under any Letters of Credit
      shall automatically become immediately due and payable and Bank shall not be
      obligated to make further Advances or issue any Letters of Credit under this
      Agreement.”

     

    
      
         

      

      
         

        
          

        

      

      
         

      

    

     

    8.    The
      following Section 10.2 (m) is added to the Agreement:

     

    “(m)
      the
      occurrence of an Event of Default under and as defined in the U.S. Concrete
      Credit Agreement or the occurrence of an Event of Default under and as defined
      in the Levy Credit Agreement, and (in either case) continuance of any such
      Event
      of Default for a period of thirty (30) days;

     

    9.    Each
      Company hereby represents and warrants that, after giving effect to the
      amendments contained herein, (a) execution, delivery and performance of this
      Amendment and any other documents and instruments required under this Amendment
      or the Agreement are within its corporate powers, have been duly authorized,
      are
      not in contravention of law or the terms of such Company’s Articles of
      Organization or Operating Agreement, and do not require the consent or approval
      of any governmental body, agency, or authority; and this Amendment and any
      other
      documents and instruments required under this Amendment or the Agreement, will
      be valid and binding in accordance with their terms; (b) the continuing
      representations and warranties of Companies set forth in Sections 6.1 through
      6.5 and 6.7 through 6.14 of the Agreement are true and correct on and as of
      the
      date hereof with the same force and effect as made on and as of the date hereof;
      (c) the continuing representations and warranties of Companies set forth in
      Section 6.6 of the Agreement are true and correct as of the date hereof with
      respect to the most recent financial statements furnished to the Bank by
      Companies in accordance with Section 7.1 of the Agreement; and (d) no Event
      of
      Default (as defined in the Agreement) or condition or event which, with the
      giving of notice or the running of time, or both, would constitute an Event
      of
      Default under the Agreement, as hereby amended, has occurred and is continuing
      as of the date hereof.

     

    10.    Except
      as
      expressly provided herein, all of the terms and conditions of the Agreement
      remain unchanged and in full force and effect.

     

    11.    Companies
      hereby waive, discharge, and forever release Bank, Bank’s employees, officers,
      directors, attorneys, stockholders and successors and assigns, from and of
      any
      and all claims, causes of action, allegations or assertions that Companies
      has
      or may have had at any time up through and including the date of this Amendment,
      against any or all of the foregoing, regardless of whether any such claims,
      causes of action, allegations or assertions arose as a result of Bank’s actions
      or omissions in connection with the Agreement, or any amendments, extensions
      or
      modifications thereto, or Bank’s administration of debt evidenced by the
      Agreement or otherwise.

     

    12.    This
      Amendment shall be effective upon (a) execution of this Agreement by Companies
      and the Bank, (b) execution by the Guarantor of the attached Reaffirmation
      of
      Guaranty, (c) delivery by Companies to Bank of an executed Revolving Credit
      Note
      in form acceptable to Bank, and (d) delivery by U.S. Concrete, Inc. and Edw.
      C.
      Levy Co. of the Support Letters in form and substance satisfactory to Bank,
      together with authorizing resolutions as required by Bank.

     

    
      
         

      

      
         

        
          

        

      

      
         

      

    

     

    


    IN
      WITNESS the due execution hereof as of the day and year first above
      written.

     

    
      	COMERICA
              BANK	 	 	SUPERIOR MATERIALS,
              LLC
              
	 	 	 	 	 	 
	By:	/s/ Rodney
              Clark	 	 	By:	/s/ Robert
              Hardy
	 	
              
Rodney
              Clark	 	 	 	
              
Robert
              Hardy
	Its:	Vice
              President	 	 	Its:	Vice
              President
	 	 	 	 	 	 
	 	 	 	 	 	 
	 	 	 	 	BWB,
              LLC
	 	 	 	 	 	 
	 	 	 	 	 	 
	 	 	 	 	By:	Curt Lindeman
	 	 	 	 	 	
              
Curt
              Lindeman
	 	 	 	 	Its:	Vice President 


    

     

     

     

    
      
         

      

      
         

        
          

        

      

      
         

      

    

    
REAFFIRMATION
      OF GUARANTY

     

    The
      undersigned acknowledges the foregoing Fifth Amendment and ratifies and confirms
      its obligations under its Guaranty of Companies’ obligations to the Bank and
      acknowledges that the Guaranty remains in full force and effect in accordance
      with its terms subject to no setoff, defense or counterclaim.

    


    August
      6,
      2008

    


    
      	 	 	 
	 	
              SUPERIOR
                MATERIALS HOLDINGS, LLC

            
	 
 	 
 	 
 
	Date: 	By:  	/s/ Robert
              Hardy
	 	
              
Robert
              Hardy
	 	Its:	Vice
              President


    

     

     

     

    


       

    


    
      
         

      

      
         

        
          

        

      

      
         

      

    


    As
      of
      August 5, 2008

    


    


    Mr.
      Rodney Clark

    Comerica
      Bank

    One
      Detroit Center

    500
      Woodward Avenue

     

    Gentlemen:

     

    Comfort
      Letter In Support of Superior Materials, LLC and BWB,
      LLC

     

     

    To
      induce
      the Bank to continue to provide Superior Materials, LLC and BWB, LLC (the
“Borrowers”) with a $17,500,000 line of credit, Comerica Bank (“Bank”) has
      requested that U.S. Concrete, Inc. (“USC”) document its support of the Borrowers
      and Borrowers’ relationship to the Bank under the line of credit. 

     

    USC
      agrees to provide, or obtain from a third party acceptable to the Bank in the
      exercise of its reasonable discretion subordinated capital (issued on terms
      and
      conditions acceptable to the Bank in the exercise of its reasonable credit
      judgement) to maintain the Borrowers’ operations on a cash flow neutral basis
      (cash flow neutral defined as net income plus, depreciation, amortization,
      non-cash charges related to asset impairment and other non-cash charges
      acceptable to the Bank minus, paid current maturities plus, equity/sub debt
      injections, plus at the Banks discretion and prior approval cash contributions
      from asset sales or other cash injections) measured on a quarterly cumulative
      basis beginning July 1, 2008 through March 31, 2009 and a rolling 4 quarter
      basis thereafter; provided that we shall not be obligated to inject more than
      $3,750,000 during any rolling 4 quarter period of the Borrowers, with a maximum
      amount of $6,750,000 for the term of the loan. Required capital injections
      are
      to be made no later than the required delivery of the Borrowers covenant
      compliance for the preceding quarter as defined in the Loan Agreement.


     

    USC
      confirms and acknowledges that its performance of all of the terms herein
      contained is necessary, and substantial performance in good faith shall not
      be
      deemed sufficient performance. Further, USC acknowledges that its strict
      performance is deemed to be the essence of this Comfort Letter and a primary
      basis upon which you have agreed to continue to extend credit to Borrowers.
      Therefore, USC specifically waives any and all defenses, whether legal or
      equitable, which USC might raise against Bank and agree that USC shall have
      no
      defense to Bank’s enforcement of strict performance of all of the terms herein
      contained.

     

    
      
         

      

      
         

        
          

        

      

      
         

      

    

    


     

    The
      construction, interpretation, invalidity and enforceability of this comfort
      letter shall be governed in all respects by the laws of the State of Michigan,
      without regard to its conflict of laws principles.

     

    This
      is a
      continuing comfort letter and may not be released, altered, modified or amended
      except by agreement in writing executed by USC and the Bank. 

     

    USC
      AND
      BANK ACKNOWLEDGE THAT THE RIGHT TO TRIAL BY JURY IS A CONSTITUTIONAL ONE, BUT
      THAT IT MAY BE WAIVED. EACH PARTY, AFTER CONSULTING (OR HAVING HAD THE
      OPPORTUNITY TO CONSULT) WITH COUNSEL OF THEIR CHOICE, KNOWINGLY AND VOLUNTARILY,
      AND FOR THEIR MUTUAL BENEFIT, WAIVE ANY RIGHT TO TRIAL BY JURY IN THE EVENT
      OF
      LITIGATION REGARDING THE PERFORMANCE OR ENFORCEMENT OF, OR IN ANY WAY RELATED
      TO, THIS COMFORT LETTER.

     

    USC
      confirms and agrees that the Bank shall be entitled to rely on this comfort
      letter in extending credit facilities to Borrowers.

     

    
      	
              Very
                Truly Yours,

              


              /s/
                Robert Hardy

              


              Robert
                Hardy

              Executive
                Vice President and Chief Financial
                Office