<PAGE>   1
                                                                    EXHIBIT 10.2

                                                                [EXECUTION COPY]




                          LIMITED PARTNERSHIP AGREEMENT

                                       OF

                         TEXAS LEHIGH CEMENT COMPANY LP

                                 by and between

                              TEXAS CEMENT COMPANY

                                       and

                         LEHIGH PORTLAND CEMENT COMPANY


                              Dated October 1, 2000


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                                TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                                                          Page
                                                                                                          ----
<S>              <C>                                                                                      <C>
ARTICLE I        DEFINITIONS...............................................................................1
                 1.1.    Definitions.......................................................................1
                 1.2.    Other Definitions.................................................................3

ARTICLE II       CONTINUATION OF THE PARTNERSHIP...........................................................3
                 2.1.    Continuation......................................................................3
                 2.2.    Interests in Partnership..........................................................3
                 2.3.    Name..............................................................................3
                 2.4.    Principal Place of Business.......................................................3
                 2.5.    Registered Agent and Registered Office............................................4
                 2.6.    Purpose and Scope.................................................................4
                 2.7.    Restrictions on Activities; Independent Activities................................4

ARTICLE III      CAPITAL CONTRIBUTIONS.....................................................................4
                 3.1.    Initial Capital Contribution of the Partners......................................4
                 3.2.    Additional Capital................................................................4
                 3.3.    Other Matters Relating to Capital Contributions...................................5
                 3.4.    Tax Indemnification...............................................................5

ARTICLE IV       TERM......................................................................................6

ARTICLE V        the GENERAL PARTNERS; MANAGEMENT OF THE PARTNERSHIP.......................................6
                 5.1.    The General Partners..............................................................6
                 5.2.    Management Committee..............................................................6
                 5.3.    Officers..........................................................................7
                 5.4.    President and Chief Operating Officer.............................................7
                 5.5.    Major Decisions...................................................................8
                 5.6.    Exculpation.......................................................................9
                 5.7.    Indemnification..................................................................10
                 5.8.    Employee Benefits................................................................10
                 5.9.    Services to the Partnership......................................................10
                 5.10.   Tax Matters Partner..............................................................11

ARTICLE VI       the limited partners.....................................................................11
                 6.1.    The Limited Partners.............................................................11
                 6.2.    No Management by the Limited Partners............................................11
                 6.3.    Liability of the Limited Partners................................................11
</TABLE>


                                        i
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<TABLE>
<CAPTION>
<S>              <C>                                                                                      <C>
ARTICLE VII      BOOKS AND RECORDS........................................................................11

ARTICLE VIII     ALLOCATIONS, DISTRIBUTIONS, AND INTERESTS................................................12
                 8.1.    Allocation of Income or Loss.....................................................12
                 8.2.    Distribution of Available Cash...................................................12
                 8.3.    Allocation of Income and Loss and Distributions in Respect of Interests
                         Transferred......................................................................12

ARTICLE IX       Transfers of Interests in Partnership....................................................13
                 9.1.    Prohibited Transfers.............................................................13
                 9.2.    Right of Sale and First Purchase.................................................13
                 9.3.    Transfers by Partners to Affiliates..............................................14

ARTICLE X        Dissolution..............................................................................14
                 10.1.   Dissolution Events...............................................................14
                 10.2.   Termination and Winding Up of Partnership........................................16
                 10.3.   Reserves.........................................................................16
                 10.4.   Cancellation of Partnership Certificate..........................................17
                 10.5.   Option at Dissolution............................................................17
                 10.6.   Closing..........................................................................17

ARTICLE XI       FAILURE TO MAKE CONTRIBUTIONS............................................................18
                 11.1.   Options of Nondelinquent Partners................................................18
                 11.2.   Voting Rights....................................................................18

ARTICLE XII      APPRAISAL................................................................................19
                 12.1.   Selection of Appraisers..........................................................19
                 12.2.   Appointment of Appraisers........................................................19
                 12.3.   Costs of Appraisal...............................................................20

ARTICLE XIII     MISCELLANEOUS............................................................................20
                 13.1.   Individual Indemnification.......................................................20
                 13.2.   Specific Performance.............................................................20
                 13.3.   Notices..........................................................................20
                 13.4.   Assumed Name Certificate.........................................................21
                 13.5.   Ownership........................................................................21
                 13.6.   Limits of Partnership, Authority and Responsibility..............................21
                 13.7.   Arms Length Transactions.........................................................22
                 13.8.   Additional Documents and Acts....................................................22
                 13.9.   Interpretation...................................................................22
                 13.10.  Terms............................................................................22
                 13.11.  Amendment........................................................................22
                 13.12.  References to this Agreement.....................................................22
</TABLE>



                                       ii
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<TABLE>
<S>                                                                                                      <C>
                 13.13.  Headings.........................................................................22
                 13.14.  Severability.....................................................................23
                 13.15.  No Third Party Beneficiary.......................................................23
                 13.16.  Binding Effect...................................................................23
                 13.17.  Counterparts.....................................................................23
                 13.18.  Complete Agreement...............................................................23
</TABLE>

EXHIBITS:

Exhibit A:      Market Area



                                       iii
<PAGE>   5

                          LIMITED PARTNERSHIP AGREEMENT


         This Limited Partnership Agreement is made and entered into on
September 29, 2000, to be effective as of 12:01 a.m. on October 1, 2000 (the
"Effective Date"), between Texas Cement Company, a Nevada corporation ("TCC"),
and Lehigh Portland Cement Company, a Pennsylvania corporation ("Lehigh").

                                    RECITALS

         Effective as of April 1, 1986 (the "Joint Venture Effective Date"),
Texas Cement Company, a Nevada corporation and a predecessor of TCC ("Old TCC"),
Centex Cement Enterprises, Inc., a Nevada corporation ("CCE"), and Lehigh formed
a joint venture partnership (the "Joint Venture") under the laws of the State of
Texas for the purpose of manufacturing, marketing and selling grey cement
products. As a result of one or more mergers, assignments and other
transactions, TCC currently holds the interest in the Joint Venture formerly
held by Old TCC and CCE (the "Original TCC Parties"). The rights, duties and
obligations of the parties with regard to the Joint Venture are governed by the
Joint Venture Agreement, dated as of March 25, 1986 and effective as of April 1,
1986 (the "Joint Venture Agreement"), between the Original TCC Parties and
Lehigh.

         As of the Effective Date, the Joint Venture will be converted into a
Texas limited partnership (the "Partnership") as a result of the filing of a
Certificate of Limited Partnership in the office of the Secretary of State of
the State of Texas. Accordingly, the parties desire to enter into this Limited
Partnership Agreement in order to provide for certain matters in connection with
the conversion of the Joint Venture into the Partnership, which agreement shall,
except as expressly stated herein, supersede the Joint Venture Agreement in its
entirety.

         NOW, THEREFORE, in consideration of the mutual covenants set forth
herein, and for other good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, TCC and Lehigh hereby agree as
follows:

                                    ARTICLE I

                                   DEFINITIONS

         1.1. Definitions. When used in this Agreement, the following terms will
have the meanings set forth below:


                  (a) "Act" shall mean the Texas Revised Limited Partnership Act
(Tex. Rev. Civ. Stat. Ann. art. 6132a-1), as the same may be amended from time
to time, or any successor statute thereto.

                  (b) "Affiliate" shall mean a person directly or indirectly,
through one or more intermediaries, controlling, controlled by or under common
control with the person in


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<PAGE>   6

question. The term "control", as used in the immediately preceding sentence,
means, with respect to a person that is a corporation, the right to the
exercise, directly or indirectly, of more than 50% of the voting rights
attributable to the shares of the controlled corporation and, with respect to a
person that is not a corporation, the possession, directly or indirectly, of the
power to direct or cause the direction of the management or policies of the
controlled person. Notwithstanding the foregoing, the Partnership shall not be
deemed an Affiliate of any Partner for purposes of this Agreement.

                  (c) "Agreement" shall mean this Limited Partnership Agreement
of the Partnership, as amended from time to time.

                  (d) "Available Cash" of the Partnership shall mean all cash
funds which are available for distribution as determined by the Management
Committee.

                  (e) "Budget" shall mean an annual operating and capital budget
to be prepared for the Management Committee, in form and content approved by the
Management Committee.

                  (f) "Code" shall mean the Internal Revenue Code of 1986, as
the same may be amended from time to time, or any successor statute thereto.

                  (g) "Fiscal Year" shall mean the twelve month period ending
December 31 of each year.

                  (h) "General Partners" shall mean the general partners of the
Partnership, and "General Partner" shall mean any of the General Partners. (i)
"Independent Accountants" shall mean Arthur Andersen LLP or such other
nationally recognized accounting firm as may be chosen by the Management
Committee.

                  (j) "Limited Partners" shall mean the limited partners of the
Partnership, and "Limited Partner" shall mean any of the Limited Partners.

                  (k) "Management Committee" shall mean the committee
designated, and with the powers and duties as provided, in Article V.

                  (l) "Market Area" means the geographic area designated in
Exhibit A hereto.

                  (m) "Partners" shall mean the General Partners and the Limited
Partners, and "Partner" shall mean any of the Partners.

                  (n) "Partnership" shall mean the limited partnership continued
pursuant to the terms hereof for the limited purposes and scope set forth
herein, and for periods prior to the Effective Date, such term shall include the
Joint Venture.


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                  (o) "Partnership Percentage Interest" shall mean as to each of
TCC and Lehigh, an interest in the capital, profits and losses of the
Partnership as follows:

<TABLE>
<CAPTION>
                                         PARTNERSHIP PERCENTAGE INTEREST HELD     PARTNERSHIP PERCENTAGE INTEREST
                                                         AS A                                HELD AS A
                PARTNER                             GENERAL PARTNER                       LIMITED PARTNER
                -------                  ------------------------------------     -------------------------------
<S>                                      <C>                                      <C>
TCC                                                        0.1%                                  49.9%
Lehigh                                                     0.1%                                  49.9%
</TABLE>


         1.2. Other Definitions. The following terms are defined in the sections
of this Agreement respectively indicated:


<TABLE>
<CAPTION>
            Term                                      Section
            ----                                      -------
<S>                                                   <C>
Delinquent Partner                                     11.1
Effective Date                                        Preamble
Joint Venture                                         Preamble
Joint Venture Agreement                               Preamble
Joint Venture Effective Date                          Preamble
Lehigh                                                Preamble
Nondelinquent Partners                                 11.1
Offering Partner                                        9.2(a)
Partnership                                           Preamble
Receiving Partners                                     12.1
Responding Partner                                      9.2(a)
Submitting Partner                                     12.1
TCC                                                   Preamble
</TABLE>

                                   ARTICLE II

                         CONTINUATION OF THE PARTNERSHIP

         2.1. Continuation. The Partners do hereby continue the Partnership
under the Act for the limited purposes and scope set forth herein and upon the
terms, provisions and conditions set forth in this Agreement. Except as
otherwise specifically provided in this Agreement, the rights and obligations of
the Partners and the continuation, administration and termination of the
Partnership shall be governed by the Act.

         2.2. Interests in Partnership. Each of the Partners shall have an
interest in the capital, profits and losses of the Partnership as specified in
this Agreement.

         2.3. Name. The name of the Partnership shall be Texas Lehigh Cement
Company LP, under which all business and affairs of the Partnership shall be
conducted.

         2.4. Principal Place of Business. The principal place of business of
the Partnership shall be located at Buda, Texas, or at such other place as shall
be approved by the Partners.


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<PAGE>   8


         2.5. Registered Agent and Registered Office. The registered agent for
service of process on the Partnership in the State of Texas shall be Corporation
Service Company, and the address of such registered agent and of the registered
office of the Partnership in the State of Texas shall be 800 Brazos, Suite 750,
Austin, Texas 78701.

         2.6. Purpose and Scope. Subject to the provisions of this Agreement,
the purposes of the Partnership are (a) manufacturing, marketing and selling
grey cement products of any type, fly ash and slag, within the Market Area, as
set forth in Exhibit A; and (b) doing any and all other acts or things which may
be incidental or necessary to carry on the business of the Partnership as herein
contemplated.

         2.7. Restrictions on Activities; Independent Activities.


         No Partner nor any of its Affiliates shall offer to sell or sell any
grey cement products, fly ash or slag in the Market Area. Except as is
prohibited by the preceding sentence, each Partner, and each of its Affiliates,
notwithstanding the existence of this Agreement, may engage in whatever
activities it chooses (including without limitation activities in the
manufacture and sale of white cement), without having or incurring any
obligation to offer any interest in any such activities to the Partnership or
any party hereto. Neither this Agreement nor any activity undertaken pursuant
hereto shall prevent any Partner or its Affiliates from engaging in such
activities, or require participation in such activities by the other Partners,
and as a material part of the consideration hereof each Partner hereby waives,
relinquishes and renounces any such right of or claim to participation in any
such activities.

                                  ARTICLE III

                              CAPITAL CONTRIBUTIONS

         3.1. Initial Capital Contribution of the Partners. Prior to the date
hereof, each Partner has made capital contributions to the Partnership as
provided in or contemplated by the Joint Venture Agreement. To the extent such
provisions have not been fully performed prior to the Effective Date, each
Partner shall continue to have such rights and obligations in respect of such
capital contributions as are set forth in the provisions of the Joint Venture
Agreement relating thereto, including, but not limited to, Article III and
Section 9.3 thereof

         3.2. Additional Capital. The Partners understand that from time to time
additional capital contributions may be necessary.

                  (a) When the Management Committee determines from time to time
that additional capital contributions are needed by the Partnership, they will
so notify the Partners, and the Partners shall make such capital contributions
within five business days of notice, prorata in accordance with their respective
Partnership Percentage Interests.

                  (b) If the President and Chief Operating Officer determines
that the continued operations of the Partnership are endangered due to the
Partnership experiencing negative cash flow and that an immediate infusion of
capital is necessary to preserve the


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<PAGE>   9

continued operations of the Partnership, he shall determine the amount of
capital necessary to preserve the operations of the Partnership and notify the
Management Committee of such circumstances and of such amount. By way of example
and not limitation, the continued operations of the Partnership would be
endangered if the Partnership were unable to meet its obligations in the
ordinary course of business, such as payroll. The Management Committee shall
meet within five days after such notice, determine the amount, if any, of
capital to be contributed and so notify the Partners. If the Management
Committee does not meet within five days of such notice or fails to agree upon
the amount, if any, of capital to be contributed, the President and Chief
Operating officer will notify the Partners of the amount of capital he deems
necessary. Each Partner shall contribute to the Partnership its prorata share of
the amount designated by the Management Committee, or by the President and Chief
Operating Officer if the Management Committee makes no determination of an
amount, within five business days of notice to the Partners.

                  (c) If a Partner fails to make a capital contribution that is
required pursuant to Section 3.2(a) or 3.2(b) above, the other Partner may
exercise the rights and, remedies as set forth in Article XI at such time.

         3.3. Other Matters Relating to Capital Contributions.

                  (a) Loans by a Partner to the Partnership shall not be
considered as capital contributions made to the Partnership.

                  (b) No Partner shall be entitled to make additional capital
contributions in excess of those contributions required or permitted under this
Article III.

                  (c) No Partner shall be entitled to withdraw, or to a return
of, any part of its capital contributions made to the Partnership, or to receive
property or assets other than cash in return thereof, except as provided in this
Agreement.

                  (d) No Partner shall be entitled to priority over another
Partner, either with respect to a return of its capital contributions made to
the Partnership, or allocations of income, gains, losses, credits or
distributions, except as provided in this Agreement.

                  (e) No interest shall be paid on capital contributions made to
the Partnership.

         3.4. Tax Indemnification. The parties to the Joint Venture Agreement
agreed to certain tax indemnification provisions set forth in Section 3.10 of
the Joint Venture Agreement. Notwithstanding anything to the contrary contained
herein, it is expressly understood and agreed that the provisions of Section
3.10 of the Joint Venture Agreement shall survive the execution and delivery of
this Agreement and shall thereafter continue in full force and effect; provided,
however, that all references in such provisions to "TCC" shall be deemed to
refer to TCC instead of the Original TCC Parties.


                                      -5-
<PAGE>   10

                                   ARTICLE IV

                                      TERM

         The term of the Partnership commenced on the Joint Venture Effective
Date and shall continue, unless sooner terminated as provided herein, until
March 31, 2016; provided, however, the term of the Partnership will be
automatically renewed and extended for an additional period of ten years every
ten years commencing April 1, 2016 unless, not more than twenty-four months nor
less than twelve months prior to the expiration of a then current term, a
General Partner notifies the other General Partner that the Partnership will not
be renewed and extended beyond the then current term.

                                    ARTICLE V

                              THE GENERAL PARTNERS;
                          MANAGEMENT OF THE PARTNERSHIP

         5.1. The General Partners. The General Partners of the Partnership
shall be TCC and Lehigh. Except as otherwise expressly provided herein or as
required by law, the business of the Partnership shall be managed, conducted and
controlled by the General Partners through the Management Committee and by
delegation of authority to the officers of the Partnership as provided herein.

         5.2. Management Committee. Each General Partner shall appoint two
representatives to serve on the Management Committee. Until further notice, the
representatives of TCC shall be Steven R. Rowley and Richard D. Jones, Jr. and
the representatives of Lehigh shall be Helmut Erhard and Rainer Nobis. Any
General Partner may designate at any time and from time to time replacement
representatives, for any given meeting, a specified term or an indefinite
period, by a written notice of such designation to each other General Partner.

                  (a) Unless otherwise expressly provided in this Agreement,
approval by the Management Committee hereunder shall mean that the action in
question has been approved unanimously at a meeting of at least three of the
members of the Management Committee upon notice (of at least seven days prior to
any meeting), to all members as to the matter to be decided (which notice may be
waived).

                  (b) The Management Committee shall meet at such reasonable
times and places as the Management Committee shall choose, either in person or
by conference call, as deemed appropriate by any General Partner or the
Management Committee. Whenever reasonably requested by any Partner, the
Management Committee shall render a just and faithful account of all dealings
and transactions relating to the business of the Partnership.

                  (c) Any action to be taken at a meeting of the Management
Committee may be taken without a meeting, without prior notice, and without a
vote, if a consent or consents in writing, setting forth the action so taken,
shall have been signed by all of the members of the Management Committee. Such
consent shall have the same force and effect as a unanimous vote


                                      -6-
<PAGE>   11

at a meeting and may be stated as such in any document or instrument filed with
the Secretary of State of Texas. The members of the Management Committee may
participate in and hold a meeting of the Management Committee by means of
conference telephone or similar communications equipment by means of which all
persons participating in the meeting can hear each other and participation in
such a meeting shall constitute presence in person at such meeting, except where
a person participates in the meeting for the express purpose of objecting to the
transaction of any business on the ground that the meeting is not lawfully
called or convened.

         5.3. Officers. The personnel to be employed by the Partnership on a
full-time basis shall include a President and Chief Operating Officer who shall
report to the Management Committee and a Vice President-Marketing, Vice
President-Finance and Plant Manager appointed by the Management Committee, who
shall report to the President and Chief Operating Officer. The terms of office
for such persons shall be one year, and the parties currently holding such
offices shall remain in office through the end of the fiscal year in which the
Effective Date occurs. If any of these persons does not take such office, then
the Management Committee will appoint someone else.

         5.4. President and Chief Operating Officer. The President and Chief
Operating Officer shall have all the rights and powers as are necessary,
advisable or convenient to the management of the business and affairs of the
Partnership within guidelines established by the Management Committee. Without
limiting the generality of the foregoing, the President and Chief Operating
Officer shall have the following rights, duties and powers:

                  (a) To prepare annually and submit to the Management Committee
the Budget; to prepare and submit to the Management Committee, monthly, income
statements, statements of partners' capital and changes in financial position
and balance sheets; and to submit promptly, from time to time, such other
information regarding the operations, assets, business, affairs and financial
condition of the Partnership as the Management Committee or any Partner may
reasonably request;

                  (b) To purchase from or through others (i) fidelity bonds with
reputable surety companies, covering all persons having access to the
Partnership's funds, indemnifying the Partnership against loss resulting from
fraud, theft, dishonesty and other wrongful acts of such persons, and (ii)
contracts of liability, property, worker's compensation and other insurance as
may be required under applicable mortgages, agreements and other instruments and
statutes or which the President and Chief Operating Officer deems advisable,
appropriate, or convenient for the protection of the assets and affairs of the
Partnership or for any purpose convenient or beneficial to the Partnership;

                  (c) To borrow money under any line of credit established with
the approval of the Management Committee;

                  (d) To sell, dispose of, trade, exchange, convey, quitclaim,
lease, surrender, release or abandon the assets of the Partnership which are not
necessary to the operations of the Partnership and which have a value in each
instance of not more than twenty-five thousand dollars ($25,000) per asset or
group of assets sold in one transaction, all upon such terms and


                                      -7-
<PAGE>   12

conditions as the President and Chief Operating Officer may deem advisable,
appropriate or convenient;

                  (e) To assign, transfer, pledge, compromise, release or settle
any claim of the Partnership for less than full payment or to arbitrate or
consent to the arbitration of any of its disputes or controversies or to confess
a judgment against the Partnership, to the extent that such claim, dispute,
controversy or judgment arises in the ordinary course of business and the amount
at issue is less than twenty-five thousand dollars ($25,000);

                  (f) To hire and discharge employees, determine the scope of
their employment, determine their compensation and take all other customary
action on behalf of the employer Partnership with regard to all employees of the
Partnership, except as provided in Section 5.5(p). However, the positions of
President and Chief Operating Officer, Vice President-Marketing, Vice
President-Finance and Plant Manager will not fall within this right and power;
and

                  (g) To keep the General Partners equally and fully informed as
to all significant matters concerning the Partnership.

         5.5. Major Decisions. Except as expressly delegated to the officers of
the Partnership, all decisions with respect to the Partnership's business shall
require the approval of the Management Committee, including but not limited to
the decisions to take any of the following actions:

                  (a) To borrow money, incur indebtedness, enter into any loan,
issue any promissory note, prepay any indebtedness or guarantee any indebtedness
or obligation of another other than as permitted by Section 5.4(c) above;

                  (b) To select, appoint and dismiss the President and Chief
Operating Officer, and any other officers who report directly to the President
and Chief Operating Officer;

                  (c) To approve annually the Budget;

                  (d) To determine the compensation of the President and Chief
Operating Officer, and any other officers who report directly to the President
and Chief Operating Officer;

                  (e) To admit a new Partner to the Partnership, except in
connection with a transfer by a Partner of an interest to an Affiliate of such
Partner within fifteen (15) days after the Effective Date (in which case the
Affiliate shall be admitted as a Partner to the Partnership immediately upon the
execution by such Affiliate of an appropriate instrument evidencing that it will
be bound by the provisions of this Agreement);

                  (f) To possess Partnership property (real or personal), or
assign rights in specific Partnership assets or property (real or personal) for
other than Partnership purposes;

                  (g) To make any capital commitment by the Partnership;


                                      -8-
<PAGE>   13

                  (h) To sell, dispose of, trade, exchange, convey, quitclaim,
lease, surrender, release or abandon the assets of the Partnership other than as
permitted in Section 5.4(d) above;

                  (i) To lease as lessee the assets of the Partnership;

                  (j) To make, execute or deliver any general assignment for the
benefit of creditors of the Partnership, or any bond, guarantee, indemnity or
surety bond of the Partnership;

                  (k) To assign, transfer, pledge, compromise, release or settle
any claim of the Partnership for less than full payment or to arbitrate or
consent to the arbitration of any of its disputes or controversies or to confess
a judgment against the Partnership other than as permitted in Section 5.4 above;

                  (l) To guarantee indebtedness owed by third parties;

                  (m) To amend or otherwise change this Agreement so as to
modify the rights or obligations of the Partners as set forth herein or alter or
modify the purpose of the Partnership;

                  (n) To do any act which would make it impossible to carry on
the ordinary business of the Partnership;

                  (o) To approve the Partnership's tax returns;

                  (p) To set compensation policy and choose, sponsor, adopt,
amend, fund and terminate employee benefit plans;

                  (q) To approve transactions, other than as provided herein,
between the Partnership and any Partner;

                  (r) To invest the Partnership's funds;

                  (s) To annually appoint the Independent Accountants;

                  (t) To permanently shut down any facility of the Partnership;
or

                  (u) To determine distributions of Available Cash of the
Partnership.

         5.6. Exculpation. Neither the Management Committee nor any member of
the Management Committee shall have any liability whatsoever to the Partnership
or any Partner, for loss caused by any act or by the failure to do any act;
provided, however, that such exculpation from liability shall not apply to any
liability for loss caused by an act or by the failure to do any act which arises
out of the gross negligence, bad faith, willful misconduct or fraud of the
Management Committee or a member thereof, as the case may be. The Management
Committee and its members shall not be deemed to be fiduciaries on behalf of the
Partnership or the Partners.


                                      -9-
<PAGE>   14

         5.7. Indemnification.

                  (a) The Partnership and each General Partner, jointly and
severally, shall indemnify any person who was, is or is threatened to be made a
named defendant or respondent in a proceeding because the person (i) is or was
an officer, employee or agent of the Partnership or member of the Management
Committee or (ii) while an officer, employee or agent of the Partnership or
member of the Management Committee, is or was serving at the request of the
Partnership as a director, officer, partner, venturer, proprietor, trustee,
employee, agent or similar functionary of another foreign or domestic
corporation, partnership, joint venture, sole proprietorship, trust, employee
benefit plan or other enterprise, unless it is determined by the Management
Committee that such person was grossly negligent, acted in bad faith or engaged
in willful misconduct or fraud. The termination of a proceeding by judgment,
order, settlement or conviction, or on a plea of nolo contendere or its
equivalent is not of itself determinative that the person did not meet the
requirements set forth in this Section 5.7.

                  (b) Notwithstanding the formation of the Partnership, each
Partner will remain solely liable for any and all claims, liabilities, costs or
expenses which are occasioned by the conduct of the business of such Partner or
its Affiliates, and the utilization of the contributed assets by such Partner or
any Affiliate, prior to the Joint Venture Effective Date, and will indemnify,
defend and hold harmless the other Partners from such claims, liabilities, costs
or expenses. This indemnification shall specifically include without limiting
the generality of the foregoing, all environmental protection matters regarding
assets contributed to the Partnership, including: (i) any claims, obligations,
costs and expenses arising at any time from the existence at the Joint Venture
Effective Date, of any underground storage tank which is leaking at such time or
which, while not leaking at the Joint Venture Effective Date was contributed to
the Partnership but was never used or intended to be used by the Partnership;
(ii) any claims, obligations, costs and expenses arising at any time from the
existence at such date of any asset containing PCB's in concentrations greater
than 50 PPM; and (iii) any claims, obligations, costs or expenses with respect
to any remedial action or cleanup required under any federal, state or local
law, statute or regulation or other liability arising at any time occasioned by
the disposal of wastes at any time prior to the Joint Venture Effective Date;
provided, however, that such claims, obligations, costs and expenses shall be
indemnified only if, and to the extent, not caused by any act or failure to act
of the Partnership or another Partner.

         5.8. Employee Benefits. The Management Committee will determine
employee benefits for the employees of the Partnership.

         5.9. Services to the Partnership. It is contemplated that, from time to
time, the Partnership will utilize the various expertise and skills possessed by
employees of the General Partners and their Affiliates. The personnel of the
General Partners and their Affiliates will be available to provide services to
the Partnership, including engineering, geological and legal services, insurance
and risk management and tax return preparation, at any reasonable time, as
authorized by the Management Committee. Such services will be at the expense of
the Partnership, and the charge for such services will be based on the actual
cost to the entity providing them. In addition, senior management of the General
Partners, or of the members of the General Partners, as applicable, will provide
reasonable advisory and consulting services to the Partnership, at no cost to
it, as requested by the Management Committee. The members of


                                      -10-
<PAGE>   15

the Management Committee shall not receive any fees or compensation for their
services on the committee.

         5.10. Tax Matters Partner. TCC shall serve as the "tax matters partner"
for all purposes under the Code.

                                   ARTICLE VI

                              THE LIMITED PARTNERS

         6.1. The Limited Partners. TCC and Lehigh shall be the limited partners
of the Partnership.

         6.2. No Management by the Limited Partners. A Limited Partner in its
capacity as such shall have no right to, and shall not, take part in the
management or control of the Partnership's business or act for or bind the
Partnership, and shall have only such rights, powers and privileges as are
expressly granted to a Limited Partner in this Agreement or are provided for
under the Act.

         6.3. Liability of the Limited Partners.

         6.4. To the maximum extent permitted by the Act, no Limited Partner
shall have any personal liability with respect to the liabilities or obligations
of the Partnership, unless such Limited Partner expressly assumes any such
liabilities or obligations. No Limited Partner shall be obligated, except as
otherwise required by law, either (i) to pay to the Partnership or to any
creditor of the Partnership or any other Partner any deficiency in its capital
account (it being understood that the obligation of the Limited Partner to make
capital contributions to the Partnership is as set forth in Article III), or
(ii) to return to the Partnership or to pay any creditor or any other Partner
the amount of any return to it of its capital contribution or other distribution
made to it. The obligation of a Limited Partner to make capital contributions to
the Partnership in accordance with Article III shall inure to the benefit of the
Partnership and the other Partners but shall not give rise to any right of any
creditor of the Partnership or other person to require a Limited Partner to make
any capital contribution to satisfy any debt, liability or obligation of the
Partnership.

                                  ARTICLE VII

                                BOOKS AND RECORDS

         The books and records of the Partnership shall, at the cost and expense
of the Partnership, be kept or caused to be kept on the accrual method of
accounting, shall reflect all Partnership transactions, and be appropriate and
adequate for conducting the Partnership's business. The Partnership shall keep
at its principal office the books and records required to be maintained by it
under Section 1.07 of the Act. The Management Committee shall cause to be
prepared all required tax returns at the Partnership's expense, and shall submit
the same to each Partner no later than 30 days prior to the due date of such
returns. Each Partner, at its own expense, shall have the right at all times to
inspect the books and records of the Partnership


                                      -11-
<PAGE>   16

during business hours at the principal place of business of the Partnership.
Annually and at the expense of the Partnership, the Independent Accountants
shall conduct an audit of the operations of the Partnership and furnish their
certified report to the Management Committee no later than 90 days after the end
of each fiscal year.

                                  ARTICLE VIII

                    ALLOCATIONS, DISTRIBUTIONS, AND INTERESTS

         8.1. Allocation of Income or Loss. The net income or net loss of the
Partnership for each Fiscal Year, and each item of Partnership income, gain,
loss and deduction as computed for federal income tax purposes, shall be
allocated to the Partners prorata in accordance with their respective
Partnership Percentage Interests.

         8.2. Distribution of Available Cash. Periodically, but not less
frequently than at the end of each Fiscal Year of the Partnership, the Available
Cash of the Partnership, if any, shall be distributed to the Partners, prorata
in accordance with their Partnership Percentage Interests, at such times and in
such amounts as determined by the Management Committee.

         8.3. Allocation of Income and Loss and Distributions in Respect of
Interests Transferred. If a Partnership Percentage Interest is transferred
during any Fiscal Year, the income or loss attributable to such interest for
such Fiscal Year shall be divided and allocated proportionately between the
transferor and the transferee based upon the number of days during such Fiscal
Year for which each party was the owner of the interest transferred; provided,
however, that if the Management Committee received a written notice stating that
such parties have agreed that such income or loss is to be allocated between
them based upon an interim closing of the Partnership books and that such
parties agree to pay all expenses incurred by the Partnership in connection with
such interim closing, then all such income or loss shall be allocated between
the transferor and transferee based upon an interim closing of the Partnership's
books and records. Distributions of Partnership assets in respect of an interest
in the Partnership shall be made only to the persons or entities who, according
to the books and records of the Partnership, are the holders of record of the
interests in respect of which such distributions are made on the actual date of
distribution. The Partnership shall incur no liability for making distributions
in accordance with the provisions of the preceding sentence, whether or not the
Management Committee or the Partnership has knowledge or notice of any transfer
or purported transfer of ownership of any interest in the Partnership.
Notwithstanding any provision of this Section 8.3 to the contrary, income or
loss resulting from a sale or other disposition of all or substantially all of
the Partnership's assets shall be allocated solely to the parties owning
interests in the Partnership as of the date such sale or other disposition
occurs.


                                      -12-
<PAGE>   17

                                   ARTICLE IX

                      TRANSFERS OF INTERESTS IN PARTNERSHIP

         9.1. Prohibited Transfers. A Partner may sell, transfer, assign or
convey all of its interest in the Partnership, but not less than all of its
interest in the Partnership, to any person, subject, in each case, however, to
the provisions of Sections 9.2 and 9.3. Any act in violation of this Article IX
shall be null and void ab initio.

         9.2. Right of Sale and First Purchase.

                  (a) Prior to entering into any contract to sell, transfer,
assign or convey all of its interest in the Partnership to a third party (other
than pursuant to Section 9.3 herein), or prior to accepting any bona fide offer
to purchase, buy or acquire all of its interest in the Partnership from a third
party, the Partner making or desiring to accept such offer (and all Affiliates
of such Partner, collectively, the "Offering Partner"), shall give written
notice of the name of the third party and all the terms, provisions and
conditions upon which the Offering Partner desires to sell its interest in the
Partnership, or in the case of receipt of a bona fide offer, a copy of the
proposed offer containing the name of the third party and all the terms,
provisions and conditions of such offer, to the other Partners who are not
Affiliates of the Offering Partner (collectively, the "Responding Partner") and
the Offering Partner shall offer to sell to the Responding Partner the Offering
Partner's interest in the Partnership on the terms, provisions and conditions
set forth in such notice.

                  (b) The Responding Partner shall have a period of 60 days from
the date of its receipt of the written notice from the Offering Partner to
accept such offer on the terms, provisions and conditions stated in such written
notice, which acceptance must be in writing and be received by the Offering
Partner prior to the expiration of such 60 day period. Any purported acceptance
which materially varies the terms of such offer shall be deemed a rejection
thereof for all purposes. The closing of the purchase by the Responding Partner
shall be held at the time and place specified in the written notice from the
Offering Partner, or such earlier date as is mutually agreed to by the Partners,
but in no event later than the day the original offer would have been closed.

                  (c) In the event the Responding Partner delivers written
notice of rejection to the Offering Partner, or in the event the Responding
Partner fails to accept the offer in the manner required by Section 9.2(b)
hereof, the offer made by the Offering Partner shall be deemed to have been
rejected by the Responding Partner and the Offering Partner shall be free to
sell, transfer, assign or convey such interest in the Partnership to the third
party named, and on the terms, provisions and conditions set forth, in the
written notice to the Responding Partner unless, within the 60 day period
provided in Section 9.2(b), the Responding Partner gives notice to the Offering
Partner that it rejects the proposed transferee, which rejection shall be made
in good faith and on a reasonable basis.

                  If the Offering Partner closes such sale to such third party,
the latter shall join in and execute with the Responding Partner a written
amendment to this Agreement pursuant to which such third party agrees to be
bound by all the terms and provisions of this Agreement


                                      -13-
<PAGE>   18

and to perform and discharge the obligations and liabilities which are
attributable to the interest acquired by such third party.

                  (d) In the event that a transaction is not consummated as
provided in Section 9.2(c) hereof on or before 180 days after the expiration of
the 60 day period provided in Section 9.2(b), or in the event any terms and
provisions of such transaction are changed following a rejection by the
Responding Partner, no sale, transfer, assignment or conveyance of such interest
in the Partnership may be made unless the provisions of this Section 9.2 are
again complied with.

                  (e) In the event that a transaction is consummated as provided
in Section 9.2(c) hereof, the purchaser shall become a new Partner in the
Partnership, upon compliance with the provisions of Section 9.2(c) hereof, under
the terms and provisions of this Agreement, together with all of the rights,
duties and obligations pertaining thereto including the rights and restrictions
contained in this Article IX with respect to subsequent sales of its interest in
the Partnership.

         9.3. Transfers by Partners to Affiliates. Notwithstanding any provision
in this Article IX to the contrary, each Partner shall be entitled, without the
consent of any other Partner, to dispose of all or any portion of its interest
in the Partnership to an Affiliate of such assigning Partner; provided, however,
(i) contemporaneously with the disposition of such interest, the Affiliate to
whom such interest is disposed shall join in and execute with the other Partners
a written amendment to this Agreement pursuant to which such Affiliate agrees to
be bound by all the terms and provisions of this Agreement and to perform and
discharge the obligations and liabilities which are attributable to the interest
acquired by such Affiliate; (ii) that following any such transfer the assigning
Partner shall continue to be bound by all the terms and provisions of this
Agreement and to perform and discharge its obligations and liabilities under
this Agreement as long as any Affiliate of such assigning Partner is a Partner
in the Partnership; and (iii) that any such transfer that would cause a
technical termination of the Partnership shall not be effected without the prior
written consent of each other Partner.

                                   ARTICLE X

                                  DISSOLUTION

         10.1. Dissolution Events.

                  (a) Except as set forth in this Article X, no Partner shall
have the right to terminate this Agreement or dissolve the Partnership by its
express will or by withdrawal without the consent of each of the other Partners
that is not an Affiliate of such Partner.

                  (b) The Partnership shall be dissolved upon the first to occur
of any of the following:

                            (i) Any General Partner shall (A) voluntarily be
         adjudicated bankrupt or insolvent, (B) seek, consent to or not contest
         the appointment of a receiver


                                      -14-
<PAGE>   19

         or trustee for itself or for all or any part of its property, (C) file
         a petition seeking relief under the bankruptcy, arrangement,
         reorganization or other debtor relief laws of the United States or any
         state or other competent jurisdiction, (D) make a general assignment
         for the benefit of its creditors, or (E) admit in writing its inability
         to pay its debts as they mature;

                            (ii) (A) A petition is filed against any General
         Partner seeking relief under the bankruptcy, arrangement,
         reorganization or other debtor relief laws of the United States or any
         state or other competent jurisdiction, or (B) a court of competent
         jurisdiction enters an order, judgment or decree appointing, without
         the consent of said General Partner, a receiver or a trustee for it or
         for all or any part of its property, and such petition, order, judgment
         or decree shall remain and shall not be discharged or stayed for 60
         days after its entry;

                            (iii) The interest in the Partnership of any General
         Partner is seized by a creditor of such General Partner and the same is
         not released from seizure or bonded out within 30 days from the date of
         notice of such seizure.

                            (iv) The Partners unanimously determine to dissolve
         the Partnership;

                            (v) The term of the Partnership, as set forth in
         Article IV above, expires;

                            (vi) A Partner has sold, transferred, assigned,
         conveyed or subjected to a security interest its interest in the
         Partnership in violation of Article IX, and the other Partners who are
         not Affiliates of such Partner elect thereafter to dissolve the
         Partnership, provided that such other Partners notify the Partner
         involved in such prohibited transaction within ninety (90) days after
         they first learn of such prohibited transaction; or

                            (vii) A decree of judicial dissolution with respect
         to the Partnership is entered under Section 8.02 of the Act; or

                            (viii) There occurs any other event that is required
         to cause the dissolution of the Partnership under the Act.

                  (c) Notwithstanding the provisions of Section 10.1(b) above,
the Partnership shall not be dissolved if:

                            (i) In the case of a dissolution resulting from any
         event specified in clauses (i) through (iii), (v) or (vi) of such
         provision, within 90 days after the occurrence of such event, all of
         the Partners (other than the Partner, if any, whose actions or status
         would otherwise result in the dissolution of the Partnership, and such
         Partner's Affiliates) agree in writing to continue the business of the
         Partnership; or

                            (ii) In the case of a dissolution resulting from an
         event of withdrawal of a General Partner (as defined in the Act),
         either (A) there remains at least one General Partner and all of the
         Partners (other than the Partner whose withdrawal would


                                      -15-
<PAGE>   20

         otherwise result in the dissolution of the Partnership, and such
         Partner's Affiliates) agree in writing to continue the business of the
         Partnership or (B) within 90 days after the occurrence of such event,
         all of the Partners (other than the Partner whose withdrawal would
         otherwise result in the dissolution of the Partnership, and such
         Partner's Affiliates) agree in writing to continue the business of the
         Partnership and, to the extent they desire or if there are no remaining
         General Partners, agree to the appointment, effective as of the date of
         withdrawal, of one or more new General Partners.

                  (d) Any dissolution of the Partnership shall be effective as
of the date on which the event occurs giving rise to such dissolution, but the
Partnership shall not terminate unless and until all its affairs have been wound
up and its assets distributed as provided in this Article X.

         10.2. Termination and Winding Up of Partnership. If the Partnership is
dissolved and no purchase is consummated under Section 10.6, an accounting of
the Partnership assets, liabilities and operations through the last day of the
month in which the dissolution occurs shall be made by the Partnership's
Independent Accountants and the affairs of the Partnership shall be wound up and
terminated. A liquidating trustee shall be designated by the Management
Committee. If the Management Committee is unable to designate the liquidating
trustee, he shall be appointed by the then Chief Judge of the District Court of
Dallas County, Texas (acting in his nonjudicial capacity or, to the extent he
refuses to act in that capacity, in his judicial capacity), upon application of
any General Partner. The liquidating trustee shall be responsible for winding up
and terminating the affairs of the Partnership and shall determine all matters
in connection therewith (including without limitation the arrangements to be
made with creditors, to what extent and under what terms the assets of the
Partnership are to be sold and the amount or necessity of cash reserves to cover
contingent liabilities) as it deems advisable and proper; provided, however,
that all decisions of the liquidating trustee shall be made in accordance with
the fiduciary duty owed by the liquidating trustee to the Partnership and each
of the Partners. The liquidating trustee shall thereafter liquidate the assets
of the Partnership as promptly as is consistent with obtaining the fair value
thereof and the proceeds therefrom shall be applied and distributed in the
following order:

                  (a) To the expenses of liquidation;

                  (b) To the payment and discharge of all the Partnership's
debts and liabilities to persons other than Partners or former Partners;

                  (c) To the payment and discharge of any loans and advances
made by Partners or former Partners to the Partnership;

                  (d) To establish and fund any cash reserve fund deemed
necessary; and

                  (e) The balance, if any, shall be distributed to the Partners
in accordance with the provisions of Section 8.2 above.

         10.3. Reserves. After all of the assets of the Partnership have been
distributed, the Partnership shall terminate; but, if at any time thereafter any
funds in any cash reserve fund


                                      -16-
<PAGE>   21

referred to in Section 10.2 above are released because the need for such cash
reserve fund has ended, such funds shall be distributed to the Partners in the
same manner as if such distribution had been made pursuant to Section 10.2
above.

         10.4. Cancellation of Partnership Certificate. Upon the completion of
the winding up of the affairs of the Partnership and the distribution of
Partnership Assets as provided in Sections 10.2 and 10.3, the Partnership shall
be terminated, and the liquidating trustee shall file or cause to be filed a
certificate of cancellation of the Certificate of Limited Partnership of the
Partnership in the office of the Secretary of State of Texas, shall cancel all
qualifications of the Partnership as a foreign limited partnership in any other
jurisdictions and shall take such other actions as it may determine are
necessary or appropriate to terminate the Partnership.

         10.5. Option at Dissolution. If the Partnership is dissolved pursuant
to Paragraphs 10.1(b)(iv), (v) or (vii), any Partner shall have, and, if the
Partnership is dissolved pursuant to Paragraphs 10.1(b)(i), (ii), (iii), (vi) or
(viii), any Partner other than the Partner (and such Partner's Affiliates) whose
acts or status prompts such dissolution thereunder shall have, and is hereby
granted, the right to buy all of the assets, subject to the liabilities, of the
Partnership. Prior to offering for sale any of the assets of the Partnership,
the liquidating trustee shall, by written notice, offer all of such assets to
the Partners entitled to buy same hereunder. If two or more Partners who are not
Affiliates desire, are entitled hereunder, and are able to buy such assets, the
liquidating trustee shall conduct an open auction in which the highest bidding
Partner (as determined by the liquidating trustee) shall be entitled to purchase
such assets. If only one Partner, together with its Affiliates, is entitled to
buy the assets hereunder, the price therefor shall be the fair market value of
those assets attributable to each nonpurchasing Partner's Partnership Percentage
Interest and shall be determined through the appraisal procedure under Article
XII.

         10.6. Closing.

                  (a) The closing of the sale and purchase of the assets of the
Partnership pursuant to Section 10.5 shall occur at the offices of the
Partnership in Buda, Texas, within 30 days after the determination of the price
for such assets.

                  (b) At closing of a sale and purchase of the assets of the
Partnership pursuant to Section 10.5, the following transactions shall occur:

                            (i) Each nonpurchasing Partner shall convey and
         assign all of its right to the assets of the Partnership to each
         purchasing Partner (or to such other person as a purchasing Partner
         shall designate to each nonpurchasing Partner), subject to the
         liabilities of the Partnership, and each nonpurchasing Partner shall
         execute and deliver to each purchasing Partner all documents which may
         be required to give effect to the sale and purchase of such assets;

                            (ii) Each purchasing Partner shall pay or cause to
         be paid to the liquidating trustee cash in the amount of the applicable
         purchase price for the assets being purchased and shall deliver to the
         liquidating trustee an agreement pursuant to which each purchasing
         Partner agrees to protect, indemnify and hold harmless the liquidating
         trustee and each nonpurchasing Partner from and against all losses,
         costs


                                      -17-
<PAGE>   22

         (including, without limitation, reasonable attorneys' fees and the cost
         of litigation), expenses, liabilities and obligations which are
         attributable to each nonpurchasing Partner's interest in the purchased
         assets and assumed liabilities from and after the date of such sale;
         and

                            (iii) The liquidating trustee shall take any
         necessary action to complete the dissolution, winding up and
         termination of the Partnership.

                                   ARTICLE XI

                          FAILURE TO MAKE CONTRIBUTIONS

         11.1. Options of Nondelinquent Partners. If any Partner fails to
contribute timely any portion of any monetary sum that it is obligated or has
otherwise agreed to contribute hereunder (such Partner and any other Partner who
is an Affiliate of such Partner being hereinafter referred to as the "Delinquent
Partner"), and the other Partners who are not Affiliates of such Partner are not
at such time Delinquent Partners, such other Partners (the "Nondelinquent
Partners") may, at their option at any time within the 90 day period following
notice of default and prior to the date such default is cured, elect any one or
more of the following rights and remedies:

                  (a) Advance the additional capital contribution required of
the Delinquent Partner as a loan by the Nondelinquent Partners to the
Partnership. Such loan shall be on such terms as the Nondelinquent Partners
shall reasonably determine and the interest rate shall be two percent over the
"prime" rate of interest quoted from time to time by Bank of America, N.A. (but
in no event in excess of the highest lawful rate) from the date of advance until
the date repaid. Notwithstanding any other provision herein, all cash flow of
the Partnership which is otherwise to be distributed to the Delinquent Partner
shall be paid first to the Nondelinquent Partners as interest (and after accrued
interest is paid, principal) on such loan until such loan is fully repaid.

                  (b) Exercise, by notifying the Delinquent Partner thereof, its
right to purchase the Partnership Percentage Interest of the Delinquent Partner
for the fair market price of the Delinquent Partner's Partnership Percentage
Interest as determined through the appraisal procedure under Article XII. The
closing of the sale and purchase of an interest pursuant to this Section 11.1(b)
shall occur at a place to be determined by the Nondelinquent Partners, within 30
days after the fair market price for such sale and, purchase is determined. Such
closing shall be conducted pursuant to the terms and provisions of Section
10.6(b).

Notwithstanding any provision in this Section 11.1 or elsewhere in this
Agreement to the contrary, no Partner, except to the extent of its interest in
the Partnership, shall have any personal liability with respect to any capital
contribution required to be made by such Partner to the Partnership pursuant to
Article III above.

         11.2. Voting Rights. Until the earliest of (i) the Delinquent Partner's
cure of its failure to make the relevant additional capital contribution, (ii)
full repayment of the loan made pursuant to Section 11.1(a), or (iii) the
closing of the sale and purchase of an interest pursuant to Section 11.1(b), the
Delinquent Partner's representatives on the Management Committee shall


                                      -18-
<PAGE>   23

have no vote on any matter to be decided or approved by the Management Committee
and approval by the Management Committee, for all purposes hereunder, shall mean
approval by only the Nondelinquent Partners' representatives on the Management
Committee.

                                  ARTICLE XII

                                    APPRAISAL

         12.1. Selection of Appraisers. A Partner requesting an appraisal
hereunder (hereinafter referred to as the "Submitting Partner") shall serve
notice to the other Partners who are not Affiliates of such Partner (hereinafter
referred to as the "Receiving Partners") stating that it elects to have the
purchase price to be paid pursuant to Section 10.5 or 11.1(b) determined by the
appraisal procedures set forth herein and the name of its appraiser. Within ten
days after receipt of such notice from the Submitting Partner, the Receiving
Partners shall notify the Submitting Partner of the name of their appraiser.
Upon appointment, the two appraisers shall be sworn to determine faithfully and
fairly the fair market price of each appropriate Partner's interest in the
Partnership, or the assets attributable thereto. The Partners shall cooperate
with, submit relevant information to, and meet with the appraisers as reasonably
requested. The two appraisers shall afford the Submitting Partner and the
Receiving Partners the right to submit evidence with respect to the price to be
determined and shall, with all possible speed, make their respective
determinations in writing and give notice thereof to the Submitting Partner and
the Receiving Partners. If there is a variance equal to or less than ten percent
in the fair market prices determined by the two appraisers, the average of the
prices so determined shall be controlling and shall be binding upon the
Submitting Partner and the Receiving Partners. If there is a variance of more
than ten percent in the fair market prices determined by the two appraisers, the
appraisers, within ten days after both of the appraisers have made their
determinations, shall appoint in writing a third appraiser and give written
notice of such appointment to the Submitting Partner and the Receiving Partners.
If the two appraisers shall fail to appoint or agree upon a third appraiser
within the ten day period, a third appraiser shall be selected by the Submitting
Partner and the Receiving Partners if they so agree upon such third appraiser
within a further period of ten days. If a third appraiser shall not be appointed
or agreed upon within the time herein provided, either the Submitting Partner or
the Receiving Partners may apply the procedure set forth in Section 12.2. The
third appraiser shall be sworn to determine faithfully and fully, pursuant to
the procedures set forth above, the question at issue. The third appraiser's
determination of price shall be controlling unless it is higher (or lower) than
the higher (or lower) determination of price of the original two appraisers, in
which case such previous high (or low) determination shall be controlling and
binding upon the Partners. The decision of the appraisers under this Section
shall be final and binding on the Partners and shall be specifically enforceable
in a court having jurisdiction.

         12.2. Appointment of Appraisers. If the Receiving Partners fail to
appoint an appraiser within ten days after their receipt of the notice from the
Submitting Partner setting forth the name of its appraiser, or any person
appointed as an appraiser by or on behalf of either the Submitting Partner or
the Receiving Partners dies, fails to act, resigns or becomes disqualified and
the party by or on behalf of whom such appraiser was appointed shall fail to
appoint a substitute appraiser within ten days after being requested to do so by
the other party,


                                      -19-
<PAGE>   24

then the sole appraiser's determination of the fair market price shall be
binding. If a third appraiser is required, but is not appointed as provided in
Section 12.1 above, the appraiser in question shall be appointed by the then
Chief Judge of the District Court of Hayes County, Texas (acting in his
nonjudicial capacity or, to the extent he refuses to act in that capacity, in
his judicial capacity), upon application of either the Submitting Partner or the
Receiving Partners.

         12.3. Costs of Appraisal. Each party shall bear and pay the cost of the
appraiser appointed by (or for) it, and the cost of the third appraiser shall be
borne and paid equally by the Submitting Partner and the Receiving Partners. The
Submitting Partner and the Receiving Partners shall be given reasonable advance
notice of the time and place of any appraisal proceedings, and both shall have
the right to be present, heard and represented by counsel. The appraisers shall
not have the power to add to or subtract from or otherwise change the terms and
provisions of this Agreement, and their determination shall be consistent and in
accordance with the terms and provisions of this Agreement. The appraisers shall
give prompt notice of their decision to each Partner.

                                  ARTICLE XIII

                                  MISCELLANEOUS

         13.1. Individual Indemnification. Any Partner who violates any of the
terms, provisions or conditions of this Agreement, or conducts any unauthorized
acts binding the Partnership, in addition to being subject to all other
remedies, liabilities and obligations that may be imposed upon it therefor,
shall indemnify, defend and hold the Partnership and the other Partners that are
not Affiliates of such Partner harmless from any and all claims, demands and
actions that may arise out of or by reason of such violation or unauthorized
acts.

         The Partnership shall indemnify, defend and save harmless the Partners,
their Affiliates, and all of their respective officers, directors, employees and
agents of and from any and all loss, damage or expense incurred by any of them
by reason of any act or omission to act on behalf of the Partnership, performed
by any of them at the Partnership's direction in good faith and in a manner
reasonably believed to be in or not opposed to the best interests of the
Partnership.

         13.2. Specific Performance. Without derogating from any other remedies
to which any Partner may be entitled, it is expressly agreed that the remedy at
law for breach of any of the obligations set forth in Sections 10.5, 10.6 and
11.1 is inadequate in view of (i) the complexities and uncertainties in
measuring the actual damages that would be sustained by reason of the failure of
a Partner to comply fully with each of said obligations, and (ii) the uniqueness
of the Partnership business and the Partnership relationship. Accordingly, each
of the aforesaid obligations shall be, and is hereby expressly made, enforceable
by specific performance.

         13.3. Notices. Any notice provided or permitted to be given under this
Agreement must be in writing, and shall be deemed delivered three days after it
is deposited in the United States mail, addressed to the Partner to be notified,
postage prepaid, and registered or certified, with a return receipt requested.
Notice served in any other manner shall be deemed to have been


                                      -20-
<PAGE>   25

given only if and when actually received by the addressee. For purposes of
notices the addresses of the Partners shall be as follows:

                    If to Lehigh:            Lehigh Portland Cement Company
                                             7660 Imperial Way
                                             Allentown, PA 18195
                                             Attention:  President

                    With a copy to:          Lehigh Portland Cement Company
                                             7660 Imperial Way
                                             Allentown, PA 18195
                                             Attention:  General Counsel

                    if to TCC:               Texas Cement Company
                                             2728 North Harwood
                                             6th Floor
                                             Dallas, Texas  75201
                                             Attention: Steven R. Rowley

                    With a copy to:          Raymond G. Smerge
                                             2728 North Harwood
                                             Dallas, Texas  75201

Failure of or delay in delivery of any copy of a notice shall not impair the
effectiveness of any notice given to any Partner as specified in this Agreement.
Each Partner may change its address for notice by the giving of notice thereof
in the manner hereinabove provided.

         13.4. Assumed Name Certificate. The Partners shall execute and file any
assumed or fictitious name certificate or certificates or any similar documents
required by law to be filed in connection with the continuation and operation of
the Partnership.

         13.5. Ownership. The interest of each Partner in the Partnership shall
be personal property for all purposes. All property and interests in property,
real or personal, owned by the Partnership shall be deemed owned by the
Partnership as an entity, legal title thereto shall be held and conveyed in the
name of the Partnership and no Partner, individually, shall have any ownership
of such property or interest owned by the Partnership except as tenants in
partnership. Each of the Partners does hereby agree to, and does hereby,
irrevocably waive, for the term of this Agreement and after dissolution and
termination of the Partnership, any right any such Partner might have to cause
the Partnership or any of its assets to be partitioned, to compel any sale of
all or any portion of the assets of the Partnership pursuant to any applicable
law or laws or to file a complaint or to institute any proceeding at law or in
equity to cause the termination or dissolution of the Partnership, except as
expressly provided for herein. Each Partner hereby acknowledges and agrees that
it has been induced to enter into this Agreement in reliance upon the mutual
waivers set forth in this Section 13.5, and without such waivers no Partner
would have entered into this Agreement.

         13.6. Limits of Partnership, Authority and Responsibility. The
relationship between and among the parties hereto shall be limited to the
carrying on of the business of the Partnership


                                      -21-
<PAGE>   26
in accordance with the terms of this Agreement. Such relationship shall be
construed and deemed to be a limited partnership for the sole and limited
purpose of carrying on such business. Except as otherwise provided for or
contemplated in this Agreement, nothing herein shall be construed to create a
partnership between the Partners nor to authorize any Partner to act as general
agent for the other Partner. No Partner, acting alone, shall have any authority
to act for, or to undertake or assume any obligation, debt, duty or
responsibility on behalf of, any other Partner or the Partnership except as
expressly otherwise provided in this Agreement. No Partner nor the Partnership
shall be responsible or liable for any indebtedness or obligation of any other
Partner incurred either before or after the execution of this Agreement, except
those responsibilities, liabilities, debts and obligations heretofore undertaken
or incurred in good faith in carrying out the purpose of the Partnership, or
hereafter undertaken or incurred on behalf of the Partnership under or pursuant
to the terms of this Agreement, or assumed in writing by the Partnership, and
each Partner hereby indemnifies and agrees to hold the other Partner harmless
from all such obligations and indebtedness except as aforesaid.

         13.7. Arms Length Transactions. All transactions of the Partnership
with the Partners and their Affiliates will be conducted on an arms length basis
except as expressly provided herein.

         13.8. Additional Documents and Acts. In connection with this Agreement,
as well as all transactions contemplated by this Agreement, each Partner agrees
to execute and deliver such additional documents and instruments and to perform
such additional acts as may be necessary or appropriate to effectuate, carry out
and perform all of the terms, provisions and conditions of this Agreement, and
all such transactions.

         13.9. Interpretation. This Agreement and the rights and obligations of
the respective parties hereunder shall be governed by and interpreted and
enforced in accordance with the laws of the State of Texas.

         13.10. Terms. Common nouns and pronouns shall be deemed to refer to the
masculine, feminine, neuter, singular and plural, as the identity of the person
or persons, firm or corporation may in the context require. Any reference to the
Code or other statutes or laws shall include all amendments, modifications or
replacements of the specific sections and provisions concerned.

         13.11. Amendment. This Agreement may not be amended, altered or
modified except by instrument in writing and signed by the parties hereto.

         13.12. References to this Agreement. Numbered or lettered articles,
sections and subsections herein contained refer to articles, sections and
subsections of this Agreement unless otherwise expressly stated. The words
"herein," "hereof," "hereunder," "hereby," "this Agreement" and other similar
references shall be construed to mean and include this Agreement and all
amendments thereof and supplements thereto unless the context shall clearly
indicate or require otherwise.

         13.13. Headings. All headings herein are inserted only for convenience
and ease of reference and are not to be considered in the construction or
interpretation of any provision of this Agreement.


                                      -22-
<PAGE>   27

         13.14. Severability. If any provision of this Agreement or the
application thereof to any person or circumstances shall be invalid or
unenforceable to any extent, the remainder of this Agreement and the application
of such provisions to other persons or circumstances shall not be affected
thereby and shall be enforced to the extent permitted by law.

         13.15. No Third Party Beneficiary. This Agreement is made solely and
specifically between and for the benefit of the parties hereto, and their
respective successors and assigns, subject to the express provisions hereof
relating to successors and assigns, and no other person, individual, corporation
or entity, whatsoever, shall have any rights, interest or claims hereunder or be
entitled to any benefits under or on account of this Agreement as a third party
beneficiary or otherwise.

         13.16. Binding Effect. Subject to the provisions of this Agreement
relating to transferability, this Agreement shall be binding upon and inure to
the benefit of the parties signatory hereto, and their respective distributees,
successors and assigns.

         13.17. Counterparts. This Agreement may be executed in a number of
counterparts, each of which shall be deemed an original and all of which shall
constitute one and the same Agreement.

         13.18. Complete Agreement. This Agreement constitutes the complete and
exclusive statement of the agreement between the Partners and replaces and
supersedes all prior agreements, by and among the Partners or any of them;
provided, however, that the execution and delivery of this Agreement shall not
relieve any party to the Joint Venture Agreement of any liability that it may
have to any other party (subject to the limitations set forth therein) as a
result of any breach occurring prior to the Effective Date of any
representation, warranty, covenant, agreement or other term or provision
contained in the Joint Venture Agreement. It is agreed that neither Partner has
rendered any services to or on behalf of either the other Partner or the
Partnership and that no Partner shall have any rights with respect to any
services which might be alleged to have been rendered, except as expressly
provided herein.


                                      -23-
<PAGE>   28

            IN WITNESS WHEREOF, the parties hereto have executed this Agreement
as of the date first above written.

                                     TEXAS CEMENT COMPANY



                                     By:  /s/ STEVEN R. ROWLEY
                                         --------------------------------------
                                     Name:  Steven R. Rowley
                                     Title:   Executive Vice President


                                     LEHIGH PORTLAND CEMENT COMPANY


                                     By:  /s/ HELMUT S. ERHARD
                                         --------------------------------------
                                     Name:    Helmut S. Erhard
                                           ------------------------------------
                                     Title:   President and CEO
                                            -----------------------------------


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