<PAGE>   1
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549
                           ---------------------------

                                    FORM T-1

                            STATEMENT OF ELIGIBILITY
                   UNDER THE TRUST INDENTURE ACT OF 1939 OF A
                    CORPORATION DESIGNATED TO ACT AS TRUSTEE

          Check if an application to determine eligibility of a Trustee
                       pursuant to Section 305(b)(2) ____

                            ------------------------

                                 CITIBANK, N.A.
               (Exact name of trustee as specified in its charter)

                                                        13-5266470
                                                     (I.R.S. employer
                                                     identification no.)

399 Park Avenue, New York, New York                         10043
(Address of principal executive office)                   (Zip Code)
                            
                            -----------------------

                               Lafarge Corporation

               (Exact name of obligor as specified in its charter)

           Maryland                                             58-1290226
(State or other jurisdiction of                              (I.R.S. employer
incorporation or organization)                              identification no.)


  11130 Sunrise Valley Drive
          Suite 300
       Reston, Virginia                                            20191
(Address of principal executive offices)                         (Zip Code)

                            -------------------------

                                 Debt Securities
                       (Title of the indenture securities)


<PAGE>   2
Item 1. General Information.

               Furnish the following information as to the trustee:

        (a)    Name and address of each examining or supervising authority to
               which it is subject.

               Name                                     Address
               ----                                     -------
               Comptroller of the Currency              Washington, D.C.

               Federal Reserve Bank of New York         New York, NY
               33 Liberty Street
               New York, NY

               Federal Deposit Insurance Corporation    Washington, D.C.

        (b) Whether it is authorized to exercise corporate trust powers.

               Yes.

Item 2. Affiliations with Obligor.

               If the obligor is an affiliate of the trustee, describe each such
               affiliation.

                     None.

Item 16. List of Exhibits.

               List below all exhibits filed as a part of this Statement of
               Eligibility.

               Exhibits identified in parentheses below, on file with the
               Commission, are incorporated herein by reference as exhibits
               hereto.

               Exhibit 1 - Copy of Articles of Association of the Trustee, as
               now in effect. (Exhibit 1 to T-1 to Registration Statement No.
               2-79983)

               Exhibit 2 - Copy of certificate of authority of the Trustee to
               commence business. (Exhibit 2 to T-1 to Registration Statement
               No. 2-29577).

               Exhibit 3 - Copy of authorization of the Trustee to exercise
               corporate trust powers. (Exhibit 3 to T-1 to Registration
               Statement No. 2-55519)

               Exhibit 4 - Copy of existing By-Laws of the Trustee. (Exhibit 4
               to T-1 to Registration Statement No. 33-34988)

               Exhibit 5 - Not applicable.


<PAGE>   3
                  Exhibit 6 - The consent of the Trustee required by Section
                  321(b) of the Trust Indenture Act of 1939. (Exhibit 6 to T-1
                  to Registration Statement No. 33-19227.)

                  Exhibit 7 - Copy of the latest Report of Condition of
                  Citibank, N.A. (as of March 31, 1998 - attached)

                  Exhibit 8 - Not applicable.

                  Exhibit 9 - Not applicable.

                                -----------------


                                    SIGNATURE

         Pursuant to the requirements of the Trust Indenture Act of 1939, the
Trustee, Citibank, N.A., a national banking association organized and existing
under the laws of the United States of America, has duly caused this statement
of eligibility to be signed on its behalf by the undersigned, thereunto duly
authorized, all in The City of New York and State of New York, on the 16th day
of June, 1998.



                                 CITIBANK, N.A.

                                 By     /s/ Arthur W. Aslanian
                                        ----------------------
                                        Vice President




<PAGE>   4
                                  EXHIBIT INDEX


Item 16. List of Exhibits.

                  List below all exhibits filed as a part of this Statement of
                  Eligibility.

                  Exhibits identified in parentheses below, on file with the
                  Commission, are incorporated herein by reference as exhibits
                  hereto.

                  Exhibit 1 - Copy of Articles of Association of the Trustee, as
                  now in effect. (Exhibit 1 to T-1 to Registration Statement No.
                  2-79983)

                  Exhibit 2 - Copy of certificate of authority of the Trustee to
                  commence business. (Exhibit 2 to T-1 to Registration Statement
                  No. 2-29577).

                  Exhibit 3 - Copy of authorization of the Trustee to exercise
                  corporate trust powers. (Exhibit 3 to T-1 to Registration
                  Statement No. 2-55519)

                  Exhibit 4 - Copy of existing By-Laws of the Trustee. (Exhibit
                  4 to T-1 to Registration Statement No. 33-34988)

                  Exhibit 5 - Not applicable.

                  Exhibit 6 - The consent of the Trustee required by Section
                  321(b) of the Trust Indenture Act of 1939. (Exhibit 6 to T-1
                  to Registration Statement No. 33-19227.)

                  Exhibit 7 - Copy of the latest Report of Condition of
                  Citibank, N.A. (as of March 31, 1998 - attached)

                  Exhibit 8 - Not applicable.

                  Exhibit 9 - Not applicable.

<PAGE>   5
                                                                      EXHIBIT 7


                                Charter No. 1461
                           Comptroller of the Currency
                              Northeastern District
                               REPORT OF CONDITION
                                  CONSOLIDATING
                              DOMESTIC AND FOREIGN
                                 SUBSIDIARIES OF

                                 CITIBANK, N.A.

         OF NEW YORK IN THE STATE OF NEW YORK AT THE CLOSE OF BUSINESS ON MARCH
         31, 1998, PUBLISHED IN RESPONSE TO CALL MADE BY COMPTROLLER OF THE
         CURRENCY, UNDER TITLE 12, UNITED STATES CODE, SECTION 161, CHARTER
         NUMBER 1461 COMPTROLLER OF THE CURRENCY NORTHEASTERN DISTRICT.

<TABLE>
<CAPTION>
                                     ASSETS
                                                                       THOUSANDS
                                                                       OF DOLLARS
<S>                                                    <C>            <C>
Cash and balances due from depository institutions:
  Noninterest-bearing balances and currency and coin...............   $  6,890,000
Interest-bearing balances..........................................     14,848,000
Held-to-maturity securities........................................              0
Available-for-sale securities......................................     31,464,000
   Federal funds sold and securities purchased under
      agreements to resell.........................................     19,345,000
Loans and lease financing receivables:
   Loans and Leases, net of unearned income.........   $159,106,000
   LESS: Allowance for loan and lease losses........      4,259,000
Loans and leases, net of unearned income, allowance, and reserve...    154,847,000
Trading assets.....................................................     36,633,000
Premises and fixed assets (including capitalized leases)...........      3,376,000
Other real estate owned............................................        485,000
Investments in unconsolidated subsidiaries and associated
   companies.......................................................      1,386,000
Customers' liability to this bank on acceptances outstanding.......      1,824,000
Intangible assets..................................................        160,000
Other assets.......................................................      9,670,000
                                                                      ------------
TOTAL ASSETS.......................................................   $280,928,000
                                                                      ============
                                  LIABILITIES
Deposits:
   In domestic offices.............................................   $ 37,884,000
   Noninterest-bearing.............................    $ 12,822,000
   Interest-bearing................................      25,062,000
In foreign offices, Edge and Agreement subsidiaries, and
   IBFs............................................................    155,776,000
   Noninterest-bearing.............................       9,878,000
   Interest-bearing................................     145,898,000
Federal funds purchased and securities sold under agreements to
   repurchase......................................................      7,429,000
Trading liabilities................................................     29,266,000
Other borrowed money (includes mortgage indebtedness and 
obligations under capitalized leases):
   With a remaining maturity of one year or less...................      9,518,000
   With a remaining maturity of more than one year through 
   three years.....................................................      2,340,000
   With a remaining maturity of more than three years..............        898,000
Bank's liability on acceptances executed and outstanding...........      1,992,000
Subordinated notes and debentures..................................      5,600,000
Other liabilities..................................................     12,507,000
                                                                      ------------
TOTAL LIABILITIES..................................................   $263,210,000
                                                                      ============
                                 EQUITY CAPITAL
Perpetual preferred stock and related surplus......................              0
Common stock.......................................................   $    751,000
Surplus............................................................      7,604,000
Undivided profits and capital reserves.............................      9,617,000
Net unrealized holding gains (losses) on available-for-sale
   securities......................................................        443,000
Cumulative foreign currency translation adjustments................       (697,000)
                                                                      ------------
TOTAL EQUITY CAPITAL...............................................   $ 17,718,000
                                                                      ------------
TOTAL LIABILITIES, LIMITED-LIFE PREFERRED STOCK, AND EQUITY 
   CAPITAL.........................................................   $280,928,000
                                                                      ============
</TABLE>

I, Roger W. Trupin, Controller of the above-named bank do hereby declare that 
this Report of Condition is true and correct to the best of my knowledge and 
belief.
                                                                ROGER W. TRUPIN
                                                                     CONTROLLER

We, the undersigned directors, attest to the correctness of this Report of 
Condition. We declare that it has been examined by us, and to the best of our
knowledge and belief has been prepared in conformance with the instructions and
is true and correct.
                                                                PAUL J. COLLINS
                                                                   JOHN S. REED
                                                              WILLIAM R. RHODES
                                                                      DIRECTORS