Exhibit 3.28a

                                                                FILED
                                                         in the Office of the
                                                     Secretary of State of Texas

                                                             APR 3 0 1999

                                                         CORPORATIONS SECTION

                             ARTICLES OF CONVERSION
                                       OF
                                 REDI-MIX, INC.

     Pursuant to the provisions of Article 5.17 of the Texas Business
Corporation Act and Section 2.15 of the Texas Revised Limited Partnership Act,
the undersigned corporation does hereby adopt the following Articles of
Conversion for the purpose of converting Redi-Mix, Inc., a Texas corporation
(the "Converting Entity"), into Redi-Mix, L.P., a Texas limited partnership (the
"Converted Entity"), and does hereby certify as follows:

     1. The name of the Converting Entity is Redi-Mix, Inc. The Converting
Entity is a corporation incorporated under the laws of the State of Texas.

     2. A Plan of Conversion has been adopted and approved by the Converting
Entity.

     3. An executed Plan of Conversion is on file at the principal place of
business of the Converting Entity, located at 1445 MacArthur, Suite 136,
Carrollton, Texas 75007. Such executed Plan of Conversion will be on file, from
and after the conversion, at the principal place of business of the Converted
Entity, which is located at 1445 MacArthur, Suite 136, Carrollton, Texas 75007.

     4. A copy of the Plan of Conversion will be furnished by the Converting
Entity (prior to the conversion) or the Converted Entity (after the conversion),
on written request and without cost, to any shareholder of the Converting Entity
and to any partner of the Converted Entity.

     5. The number of shares of stock of the Converting Entity outstanding as of
the date hereof is seven thousand seven hundred (7,700).

     6. The number of shares of stock of the Converting Entity outstanding, not
entitled to vote only as a class, voted: (i) in favor of the Plan of Conversion
was seven thousand seven hundred (7,700); and (ii) against the Plan of
Conversion was zero (0).

     7. The Converted Entity shall be responsible for the payment of all fees
and franchise taxes required by law and for which the Converting Entity was
responsible prior to the conversion; and the Converted Entity shall be obligated
to pay any and all such fees and franchise taxes if the same are not timely paid
by the Converting Entity.

     Dated this 28th day of April, 1999.

                                        REDI-MIX, INC.,
                                        a Texas corporation


                                        By:
                                            ------------------------------------
                                        Name: John C. Miller
                                        Title: Secretary and Treasurer



                               PLAN OF CONVERSION
                                       OF
                                 REDI-MIX, INC.

     THIS PLAN OF CONVERSION (this "Plan"), dated this 27th day of April, 1999,
pursuant to Article 5.17 of the Texas Business Corporation Act is hereby adopted
by Redi-Mix, Inc., a Texas corporation (the "Converting Entity") for the purpose
of converting to a Texas limited partnership.

     1. Name of the Converting and Converted Entities. The name of the
Converting Entity is Redi-Mix, Inc., a Texas corporation. The name of the
Converted Entity is Redi-Mix, L.P., a Texas limited partnership (the "Converted
Entity").

     2. Continuation. The Converting Entity is continuing its existence in the
organizational form of the Converted Entity.

     3. Entity and Jurisdiction of Converted Entity. The Converted Entity is to
be a limited partnership, and the state under the laws of which the Converted
Entity is to be formed is Texas.

     4. Manner of Conversion of Shares. The shares of each shareholder of the
Converting Entity are hereinafter referred to as the "Shares". A general
partner's partnership interest in the Converted Entity is herein referred to as
a "General Partnership Interest" and a limited partner's partnership interest in
the Converted Entity is herein referred to as a "Limited Partnership Interest."
The manner and basis of converting the Shares of the Converting Entity into a
General Partnership Interest or a Limited Partnership Interest, as the case may
be, in the Converted Entity shall be as follows:

          (a) The Shares of Atlas Investments Inc., a Nevada corporation, in the
     Converting Entity immediately prior to the Effective Date (as defined in
     Section 7 hereof), and all rights in respect thereof shall forthwith, on
     the Effective Date, automatically, and without further action on the part
     of the Converting Entity, be converted into a 99.9% Limited Partnership
     Interest in the Converted Entity.

          (b) The Shares of Redi-Mix Management, Inc., a Texas corporation, in
     the Converting Entity immediately prior to the Effective Date (as defined
     in Section 7 hereof), and all rights in respect thereof shall forthwith, on
     the Effective Date, automatically, and without further action on the part
     of the Converting Entity, be converted into a 0.1% General Partnership
     Interest in the Converted Entity.

     Upon formation of the Converted Entity: (i) Redi-Mix Management, Inc., a
Texas corporation, shall automatically, and without further action on the part
of the Converting Entity, become the Converted Entity's General Partner; and
(ii) Atlas Investments Inc., a Nevada corporation, shall automatically, and
without further action on the part of the Converting Entity, become the
Converted Entity's Limited Partner.



     5. Organizational Documents of Converted Entity. The Articles of
Incorporation of the Converting Entity are attached hereto as Exhibit "A" and
are incorporated herein by reference.

     6. Organizational Documents of the Converted Entity. The Certificate of
Limited Partnership of the Converted Entity are attached hereto as Exhibit "B"
and is incorporated herein by reference. The Agreement of Limited Partnership of
the Converted Entity is attached hereto as Exhibit "C" and is incorporated
herein by reference.

     7. Effective Date. The conversion referred to herein shall become effective
upon the issuance of a Certificate of Conversion by the Secretary of State of
the State of Texas (the "Effective Date').

     IN WITNESS WHEREOF, the undersigned has adopted this Plan as of the date
first above written.

                                        REDI-MIX, INC.,
                                        a Texas corporation


                                        By:
                                            ------------------------------------
                                        Name: John C. Miller
                                        Title: Secretary and Treasurer


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