<PAGE>
 
                                                                   EXHIBIT 10.64

                            MASTER LEASE AGREEMENT

MASTER LEASE AGREEMENT ("Master Lease") dated as of  5/6/97 between The CIT 
Group/Equipment Financing Inc. Lessor),

having a place of business at P.O Box 27248      Tempe       AZ      85285-7248
                              -------------------------------------------------
                              Address            City       State    Zip Code

and Meadow Valley Contractors, Inc.                                   ("Lessee")
    ------------------------------------------------------------------

having a place of business at 4411 South 40th Street   Phoenix   AZ    85040
                              --------------------------------------------------
                              Address                  City     State  Zip code 

This Master Lease Agreement provides a set of terms and conditions that the 
parties hereto intend to be applicable to various transactions for the lease of 
personal property. Each lease contract shall be evidenced by an equipment 
schedule ("Schedule)" executed by Lessor and Lessee that explicitly incorporates
the provisions of this Master Lease Agreement and that sets forth specific terms
of that particular lease contract. Where the provisions of a Schedule conflict 
with the terms hereof, the provisions of the Schedule shall prevail. Each 
Schedule shall constitute a complete and separate lease agreement, independent 
of all other Schedules and without any requirement of being accompanied by an 
originally executed copy of this Master Lease Agreement. The term "Lease when 
used herein shall refer to an individual Schedule.

One originally executed copy of this Schedule shall be denominated "Originally 
Executed Copy No. 1 of 1 originally executed copies and such copy shall be 
retained by Lessor. If more than one copy of the Schedule is executed by Lessor 
and Lessee, all such other copies shall be numbered consecutively with numbers 
greater than 1. Only transfer of possession by Lessor of the originally executed
copy denominated "Originally Executed Copy No. 1" shall be effective for 
purposes of perfecting an interest in such Schedule by possession.


1.   EQUIPMENT LEASED AND TERM.

This Lease shall cover such personal property as is described in any Schedule
executed by or pursuant to the authority of Lessee accepted by Lessor in writing
and identified as a part of this Lease (which personal property with all
replacement parts, additional repairs, accessions and accessories incorporated
therein and/or affixed thereto is hereinafter called the "Equipment"). Lessor
here leases to Lessee and Lessee hereby hires and takes from Lessor, upon and
subject to the covenants and conditions hereinafter contained, the Equipment
described in any Schedule. Notwithstanding the commencement date of the term of
this Lease with respect to any item of Equipment, Lessee agrees that all risk
of loss of the Equipment shall be on Lessee from and after shipment of the
Equipment to Lessee by the seller thereof, F.O.B. seller's point of shipment,
the date of such shipment be hereinafter called "date of shipment." The term of
this Lease with respect to any item of Equipment shall be for the period as set
forth in the Schedule. Lessee hereby gives Lessor authority to insert the actual
commencement date and date of first monthly rental for an item of Equipment in
any Schedule as well as such items as serial numbers if such are not already
inserted when such Schedule executed by Lessee. "Seller" as used in this Lease
means the supplier from which Lessor acquired any item of Equipment.

2.   RENT

The aggregate rent payable with respect to each item of Equipment shall be in 
the amount shown with respect to such item on Schedule. Lessee shall pay to
Lessor the aggregate rental for each item of Equipment for the full period and
term for which Equipment is leased, such rental to be payable at such times and
in such amounts for each item of Equipment as shown in applicable Schedule.

All rent shall be paid at Lessor's place of business shown above, or such other 
place as Lessor may designate by written notice to Lessee. All rents shall be 
paid without notice or demand and without abatement, deduction or set off of any
amount whatsoever. The operation and use of the Equipment shall be at the risk
of Lessee and not of Lessor and the obligation of Lessee pay rent hereunder
shall be unconditional.
<PAGE>
 
19.  SPECIAL PROVISIONS



If Lessee is a corporation, this Lease is executed by authority of its Board of 
Directors. If Lessee is a partnership or joint venture, this Lease is executed 
by authority of all its partners or co-ventures.

Dated:     5/6/97
      ---------------------
 
LESSEE:

Meadow Valley Contractors, Inc.
------------------------------------------------------------
Name of individual, corporation or partnership

By /s/ Kenneth D. Nelson           Title  Vice President
  --------------------------------      ---------------------
  If corporation, have signed by President, Vice President
  or Treasurer, and give official title, if owner or partner, 
  state which.
  

LESSOR:

THE CIT GROUP/EQUIPMENT FINANCING, INC.

By [SIGNATURE ILLEGIBLE]          Title  Scom
  --------------------------------     ---------------------
________________________________________________________________________________
If Lessee is a partnership, enter:
Partners' names                             Home addresses 
---------------                             --------------

                                                                  Page 7 of ???

<PAGE>
      
 
                                                        ________________________
                                                        Date

THE CIT GROUP/EQUIPMENT FINANCING, INC.

P. O. BOX 27248
-------------------------------------------------------
Address

Tempe                            AZ        85285-7248
-------------------------------------------------------
City                             State     Zip Code


Gentlemen:

You are irrevocably instructed to disburse the proceeds of the Schedule of 
Leased Equipment No. 2 dated __________________________, to Master Lease 
Agreement dated May 6, 1997, between Meadow Valley Contracting, Inc., as Lessee 
and the CIT Group/Equipment Financing., as Lessor, as follows:

<TABLE> 
<CAPTION> 
            Payee Names and Addresses                                                     Amount
-----------------------------------------------                                   --------------------
<S>                                                                               <C> 
Meadow Valley Contractors, Inc.                                                   $        158,140,00
                                                                                    ------------------

                                                                                  $ __________________ 

The CIT Group/Equipment Financing, Inc. (Non Refundable Processing Fees)          $            350,00
                                                                                    ------------------

                                                                                  $ __________________ 

                                                                                  $ __________________ 

                                                                                  $ __________________ 

                                                                                  $ __________________  


                                                                  Total Proceeds  $        158,490.00
                                                                                    ------------------
</TABLE> 

Very truly yours,


Meadow Valley Contractors, Inc.
------------------------------------------------------
By     Gary W. Burnell         Title  VP/CFO
  -----------------------------     ------------------

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