Exhibit 3.81

                                     BY-LAWS

                                       OF

                             TEXAS DRY CONCRETE CO.

                                   ----------

     1. All meetings of the shareholders and directors shall be held in the City
of Dallas, State of Texas, at such other place as the shareholders or directors,
as the case may be, shall agree to.

     2. The shareholders shall hold an annual meeting on the second Tuesday of
September at 2:00 o'clock P.M. of each year for the purpose of electing
directors and for the transaction of such other business as may come before the
meeting.

     3. The shareholders may hold a special meeting at any time on the call of
the president, the board of directors, or by the holders of not less than
one-tenth of all shares entitled to vote at the meeting.

     4. Written notice of each meeting of the shareholders, stating the purpose
or purposes of such meeting, must be mailed to the last known post office
address of each shareholders not less than ten (10) nor more than fifty (50)
days before the date of the meeting, or each shareholder must waive notice of
the meeting.

     5. At each meeting of the shareholders; each shareholder entitled to vote
thereat shall he entitled to one vote for each outstanding share held by such
shareholder. A shareholder may vote either in person or by proxy. All questions
coming before such meetings, except as otherwise provided by statute or by these
by-laws, shall be determined by the vote of a majority in interact of the
shareholders present



or represented. The holders of a majority of the shares entitled to vote
represented in person or by proxy shall constitute a quorum for the transaction
of business.

     6. Any action required by statute to be taken at a meeting of the
shareholders or any action which may be taken at a meeting of the shareholders
may be taken without a meeting if a consent in writing setting forth the action
so taken shall be signed by all of the shareholders entitled to vote with
respect to the subject matter thereof.

     7. The corporate powers of this corporation shall be exercised and its
business, property and interest shall be conducted and controlled by the board
of directors, which may exercise all such powers of the corporation and do all
such lawful acts and things as are not by statute or by the articles of
incorporation or by these by-laws directed or required to be exercised and done
by the shareholders.

     8. The number of directors of this corporation shall be not less than three
(3) nor more than seven (7). The present board shall consist of 3 directors, and
hereafter, within the foregoing limitation, the number of directors shall be
determined by resolutions of the board of directors or of the shareholders. Any
and each director shall be subject to removal at any time by the vote of the
holders of the majority of the outstanding shares of this corporation. Any
vacancy occurring in the board of directors may be filled by the affirmative
vote of a majority of the remaining directors though less than a quorum of the
board of directors. A director elected to fill a vacancy shall be elected for
the unexpired term of his predecessor in office. Any directorship to be filled
by reason of an increase in the number of



directors shall be filled by election at an annual or at a special meeting of
the shareholders called for that purpose.

     9. The board of directors shall hold one regular meeting each year without
notice immediately following the annual meeting of shareholders. Special
meetings of the board of directors may be called by the president and shall be
called on the request of any two directors. Written notice of each special
meeting of the board of directors must be mailed to the last known post office
address of each director at least three (3) days prior to the meeting, or each
director must waive notice of the meeting. Attendance of a director at a
directors' meeting shall constitute a waiver of notice of such meeting except
where a director attends a meeting for the purpose of objecting to the
transaction of any business on the ground that the meeting is not lawfully
called or convened.

     10. A majority of the directors shall constitute a quorum for the
transaction of business, and the act of a majority of the directors present at
any meeting at which a quorum is present shall be the act of the board of
directors.

     11. The board of directors shall have the power to delegate any of its
powers in relation to the ordinary business of this corporation to any officer
or agent upon such terms as it may think fit.

     12. The officers of this corporation shall consist of a president, one or
more vice-presidents, a secretary, and a treasurer, and such additional officers
as the directors may determine, each of whom shall be elected by the board of
directors. Any two or more offices may be held by the same person except that
the president and secretary shall not be the same person.



     13. Subject to special determination of duties by the board of directors,
each officer of this corporation shall exercise the powers and perform the
duties usually appertaining to his office.

     14. Any officer or agent of this corporation elected or appointed by the
board of directors may be removed by the board of directors or the holders of
the majority of the outstanding shares of this corporation whenever in their
judgment the best interests of this corporation will be served thereby. Any
vacancy occurring in any office of this corporation by death, resignation,
removal, or otherwise, shall be filled by the board of directors.

     15. The board of directors shall determine the form of stock certificate
to be issued by this corporation and shall cause one or more certificates under
the seal of the corporation to be signed by the president or a vice-president
and the treasurer or secretary, and to be issued to each shareholder certifying
the number of shares owned by such shareholder.

     16. The shares of stock of this corporation shall be transferable only upon
its books by the holders thereof, in person, or by their duly authorized
attorneys or legal representatives, and upon such transfer, the old certificates
shall be surrendered to the corporation by delivery thereof to the person in
charge of the stock and transfer books and ledgers, or to such other person as
the directors may designate, by whom such certificates shall be cancelled and
new certificates shall thereupon be issued. A record shall be made of each
transfer.

     17. Whenever any notice is required by these by-laws to be given, it shall
be in writing and delivered in person or mailed to



the directors or shareholders at their addresses appearing on the books of the
corporation. Notice by mail shall be deemed to be given at the time when the
same shall be mailed. Any notice required to be given under the provisions of
statute or of the articles of incorporation or of these by-laws may be waived by
the person entitled thereto.

     18. The corporate seal of this corporation shall have inscribed thereon the
name of the corporation. It may be used by causing it or a facsimile thereof to
be impressed or affixed or in any other manner reproduced.

     19. These by-laws may be altered, amended or repealed in whole or in part
at any regular or special meeting of the board of directors or the shareholders.