Exhibit 10.4

[Aegion Corporation Letterhead]

Date of Grant: October 8, 2014
Employee: Charles R. Gordon
Account Number: _____________________
Threshold/Target/Maximum No. of Performance Units:
______________________

Performance Unit Agreement for Charles R. Gordon

This Agreement will certify that the employee named above (“you”) is awarded the
number of performance units shown above (“Performance Units”), effective as of
the date of grant set forth above (“Date of Grant”). Each Performance Unit
represents the obligation of Aegion Corporation (the “Company”) to transfer one
share of Class A common stock, par value $0.01 per share (“Common Stock”) to you
at the time provided in this Agreement. This award (the “Award”) is granted to
you pursuant to the 2013 Employee Equity Incentive Plan (the “Plan”) and the
Aegion Corporation 2011 Executive Performance Plan (the “EPP”), subject to the
terms, conditions and restrictions in the Plan, the EPP and those set forth
below. Any capitalized, but undefined, term used in this Agreement shall have
the meaning ascribed to it in the Plan or the EPP, as applicable. Your signature
below constitutes your acceptance of this Award, your agreement to abide by the
Company’s Code of Conduct and your acknowledgment of your agreement to all the
terms, conditions and restrictions contained in this Agreement including that
this Agreement is accepted and entered into in the State of Missouri. You must
return an executed copy of this Agreement to the Vice President of Human
Resources, or such person’s designee, in Chesterfield, Missouri by October 15,
2014, where it will be accepted, or this Agreement shall be void. In addition,
except where prohibited by law, as a condition to the Award hereunder, you shall
be required to sign any confidentiality, non-solicitation and/or non-competition
agreement, including, without limitation, the 2014 Confidentiality, Work Product
and Non-Competition Agreement, and/or acknowledgement of the Company’s right to
recoup any incentive compensation from you as may be required by the Company.

Accepted by Employee                        AEGION CORPORATION

Charles R. Gordon                        Juanita H. Hinshaw, Chair Compensation
Committee

Terms, Conditions and Restrictions

1.Grant of Performance Units. Subject to the terms and conditions contained in
this Agreement, the Plan and the EPP, the Company hereby grants to you the
number of Performance Units designated above. The time between the Date of Grant
and the vesting of the Performance Units shall be referred to as the “Vesting
Period.”

2.Performance Goals. The vesting of Performance Units is conditioned upon the
achievement by the Company of certain cumulative two-year performance goals
(“Performance Goals”), as established by the Compensation Committee of the Board
of Directors and the vesting of such Performance Units may not occur, in whole
or in part, if such Performance Goals are not achieved.

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The cumulative Performance Goals for the performance period covered by this
Award are set forth in Appendix A to this Agreement.

3.Vesting of Performance Units upon Achievement of Performance Goals.
Performance Units vest only upon the achievement of the cumulative Performance
Goals for the performance period as set forth in Appendix A.

The vesting of Performance Units is weighted so that 75% of the maximum
Performance Units subject to this Award will vest through the achievement of the
cumulative earnings per share (“EPS”) Performance Goal (the “EPS Goal”) for a
two-year performance period (i.e., January 1, 2015 through December 31, 2016)
(the “EPS Performance Period”) and 25% of the maximum Performance Units subject
to this Award will vest through achievement of the cumulative total shareholder
return (“TSR”) Performance Goal (the “TSR Goal”) for a performance period from
the Date of Grant through December 31, 2016 (the “TSR Performance Period”), each
as set forth in Appendix A to this Agreement.

The Compensation Committee has established cumulative threshold, target and
maximum levels for each of the EPS Goal and TSR Goal for the EPS Performance
Period and the TSR Performance Period, respectively, as set forth in Appendix A.
If the Company fails to achieve the threshold levels for either of the EPS Goal
or the TSR Goal for the EPS Performance Period and the TSR Performance Period,
respectively, no Performance Units attributable to that Performance Goal shall
vest. If the Company achieves the threshold level of the EPS Goal for the EPS
Performance Period, 18.75% of the maximum Performance Units under this Agreement
shall vest, and, if the Company achieves the threshold level of the TSR Goal for
the TSR Performance Period, 6.25% of the maximum Performance Units under this
Agreement shall vest. If the Company achieves the target level for the EPS Goal
for the EPS Performance Period, 37.5% of the maximum Performance Units under
this Agreement shall vest, and, if the Company achieves the target level for the
TSR Goal for the TSR Performance Period, 12.5% of the maximum Performance Units
under this Agreement shall vest. If the Company achieves the maximum level for
the EPS Goal for the EPS Performance Period, 75% of the maximum Performance
Units eligible under this Agreement shall vest, and if the Company achieves the
maximum level for the TSR Goal for the TSR Performance Period, 25% of the
maximum Performance Units under this Agreement shall vest.

To the extent that the Company achieves greater than the threshold level of any
Performance Goal but less than the target level of such Performance Goal, or
greater than the target level of any Performance Goal but less than the maximum
level of such Performance Goal, the number of Performance Units that shall vest
shall be calculated based on a straight-line, sliding scale using the vesting
levels between which the Company’s actual performance falls as the end points
for the calculation.

In the event of your death, the termination of your employment with the Company
as a result of your disability (pursuant to the terms of any employee disability
benefit plan maintained by the Company), or the termination of your employment
as a result of your retirement (retirement means your voluntary termination of
your employment with the Company and its subsidiaries following (i) your
attainment of the age of 55 with at least 10 years of full-time service to the
Company and/or its subsidiaries, (ii) your attainment of the age of 60 with at
least five years of full-time service to the Company and/or its subsidiaries, or
(iii) your attainment of the age of 65 (with no minimum full-time service
requirements with the Company and/or its subsidiaries)), you will be entitled to
receive Performance Units if and to the extent that the cumulative EPS Goal or
the cumulative TSR Goal is achieved during the EPS Performance Period and the
TSR Performance Period, respectively. If such is the case, the Performance Units
that will vest and that you will receive due to the achievement of one or both
of the cumulative EPS Goal or the cumulative TSR Goal will be determined in the
same manner as set forth in the immediately preceding paragraph of this Section
3 but will be reduced pro rata to a percentage of that amount determined by
dividing (i) the number of whole months of your employment with the Company or a
subsidiary thereof during the EPS Performance Period or the TSR Performance
Period, as applicable, covered by this Agreement by (ii) 24, in the case of
Performance Units vesting as a result of the achievement of the cumulative EPS
Performance Goal, and 27, in the case of the achievement of the cumulative TSR
Performance Goal.

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For purposes of this Agreement, “EPS” shall be defined as “net income before
extraordinary items” of the Company, which shall mean the consolidated net
income of the Company during the fiscal year, as determined by the Compensation
Committee in conformity with accounting principles generally accepted in the
United States of America and contained in financial statements that are subject
to an audit report of the Company's independent public accounting firm, but
excluding: (a) operating results of and/or losses associated with the write-down
of assets of a subsidiary, business unit or division that has been designated by
the Board of Directors as a discontinued business operation or to be liquidated;
(b) gains or losses on the sale of any subsidiary, business unit or division, or
the assets or business thereof; (c) gains or losses from the disposition of
material capital assets (other than in a transaction described in clause (b)) or
the refinancing of indebtedness, including, among other things, any make-whole
payments and prepayment fees; (d) losses associated with the write-down of
goodwill or other intangible assets of the Company due to the determination
under applicable accounting standards that the assets have been impaired; (e)
gains or losses from material property casualty occurrences or condemnation
awards taking into account the proceeds paid by insurance companies and other
third parties in connection with the casualty or condemnation; (f) any other
material income or loss item the realization of which is not directly
attributable to the actions of current senior management of the Company; (g) any
income statement effect resulting from a change in generally accepted accounting
principles, except to the extent the effect of such a change is already
reflected in the calculation of the net income before extraordinary items; (h)
restructuring charges and acquisition related transaction costs; and (i) the
income taxes (benefits) of any of the above-designated gains or losses.
Consolidated net income of the Company shall be calculated inclusive of
operating results of any entities or businesses acquired during the EPS
Performance Period.

The Compensation Committee shall have final authority with respect to the
determination of “net income before extraordinary items” and, in exercising such
authority, may consult with the Company’s independent auditor and/or Audit
Committee as it deems necessary and advisable.

In determining “TSR”, the Compensation Committee shall establish a peer group of
companies in the S&P 1500 Construction and Oil plus any of Aegion’s 2014
14-company compensation peer group that are not included in the S&P 1500
Construction and Oil (the “Custom Peer Group” and compare the Company’s total
shareholder return (i.e., average stock price over 30-day periods immediately
prior to the start and the end of the TSR Performance Period plus dividends
paid, “TSR”) relative to the individual TSR of each member of the Custom Peer
Group.

4.
Change in Control.

In the event of a Change in Control (as defined in this Section 4 below), the
successor organization (the “Successor”) may substitute an equivalent award for
the Performance Units (a “Substitute Equivalent Award”). A Substitute Equivalent
Award must (i) have a value at least equal to the “target” value of the
Performance Units being substituted as determined by the Compensation Committee
in its sole discretion; (ii) not be subject to any performance restrictions;
(iii) relate to a publicly-traded equity security of the Successor involved in
the Change in Control or another entity that is affiliated with the Company or
the Successor following the Change in Control; (iv) except as provided herein,
be the same type of award as the Performance Units; and (v) have other terms and
conditions, including the vesting provisions in the event of termination without
“Cause” (as defined in this Section 4 below) or for “Good Reason (as defined in
this Section 4 below), that are not less favorable to you than the terms and
conditions of the Performance Units, each as determined by the Compensation
Committee in its sole discretion.

If a Substitute Equivalent Award is substituted for the Performance Units and
your employment with the Company and its subsidiaries (or the Successor and its
subsidiaries, as the case may be) is terminated by the Company or its
subsidiaries (or the Successor and its subsidiaries, as the case may be) without
Cause within two years of the Change of Control, or you terminate your
employment with the Company or its subsidiaries (or the Successor and its
subsidiaries, as the case may be) with Good Reason within two years of the
Change of Control, the Performance Units under the Substitute Equivalent Award
will immediately vest and be distributable to you upon such termination in an
amount equal to the number of Performance Units that would vest at the “target”
level for each of the Performance Goals (as set forth in Appendix A).

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If a Substitute Equivalent Award is not substituted for the Performance Units by
the Successor upon a Change in Control, the Performance Units under this
Agreement will vest immediately and be distributable to you prior to such Change
in Control in an amount equal to the number of Performance Units that would vest
at the “target” level for each of the Performance Goals (as set forth in
Appendix A).

For purposes of this Agreement:
“Cause” shall mean:
(i)
breaching any employment, confidentiality, noncompete, nonsolicitation or other
agreement with the Company, any written Company policy relating to compliance
with laws (during employment) or any general undertaking or legal obligation to
the Company;

(i)
causing, inducing, requesting or advising, or attempting to cause, induce,
request or advise, any employee, representative, consultant or other similar
person to terminate his/her relationship, or breach any agreement, with the
Company;

(ii)
causing, inducing, requesting or advising, or attempting to cause, induce,
request or advise, any customer, supplier or other Company business contact to
withdraw, curtail or cancel its business with the Company; or

(iv)
failing or refusing to perform any stated duty or assignment, misconduct,
disloyalty, violating any Company policy or work rule, engaging in criminal
conduct in connection with your employment, being indicted or charged with any
crime constituting a felony or involving dishonesty or moral turpitude,
violating any term in this Agreement, unsatisfactory job performance, or any
other reason constituting cause within the meaning of Missouri common law.

a “Change in Control” shall mean:
(i) the acquisition by one person, or more than one person acting as a group, of
ownership of stock of the Company that, together with stock held by such person
or group, constitutes more than 50% of the total fair market value or total
voting power of the stock of the Company; and/or
(ii)
the acquisition by one person, or more than one person acting as a group, of
ownership of stock of the Company, that together with stock of the Company
acquired during the twelve-month period ending on the date of the most recent
acquisition by such person or group, constitutes 30% or more of the total voting
power of the stock of the Company; and/or

(iii)
a majority of the members of the Company’s board of directors is replaced during
any twelve-month period by directors whose appointment or election is not
endorsed by a majority of the members of the Company’s board of directors before
the date of the appointment or election; and/or

(iv)
one person, or more than one person acting as a group, acquires (or has acquired
during the twelve-month period ending on the date of the most recent acquisition
by such person or group) assets from the Company that have a total gross fair
market value (determined without regard to any liabilities associated with such
assets) equal to or more than 40% of the total gross fair market value of all of
the assets of the Company immediately before such acquisition or acquisitions.

Persons will not be considered to be acting as a group solely because they
purchase or own stock of the same corporation at the same time, or as a result
of the same public offering. However, persons will be considered to be acting as
a group if they are owners of a corporation that enters into a merger,
consolidation, purchase or acquisition of stock, or similar business transaction
with the Company.

This definition of Change in Control shall be interpreted in accordance with,
and in a manner that will bring the definition into compliance with, the
regulations under Section 409A of the Internal Revenue Code (the “Code”).

“Good Reason” shall mean, without your express written consent, the occurrence
after a Change in Control of any one or more of the following:
(i)
a material reduction or alteration in the nature or status of your authorities,
duties, or responsibilities from those in effect as of 90 calendar days prior to
the Change in Control, other than an insubstantial and inadvertent act

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that is remedied by the Company or the Successor promptly after receipt of
notice thereof given by you;
(ii)
the Company’s or the Successor’s requiring you to be based at a location in
excess of 50 miles from the location of your principal job location or office in
effect as of 90 calendar days prior to the Change in Control, except for
required travel on the Company’s or the Successor’s business to an extent
substantially consistent with your then present business travel obligations;

(iii)
a material reduction by the Company or the Successor of your base salary in
effect as of 90 calendar days prior to the Change in Control; or

(iv)
the failure of the Company or the Successor to continue in effect any of the
Company’s short- and long-term incentive compensation plans, or employee benefit
or retirement plans, policies, practices, or other compensation arrangements in
which you participate taken as a whole unless such failure to continue the plan,
policy, practice, or arrangement pertains to all plan participants generally; or
the failure by the Company or the Successor to continue your participation
therein on substantially the same basis, both in terms of the amount of benefits
provided and the level of your participation relative to other participants, as
existed 90 calendar days prior to the Change in Control.

5.Forfeiture of Performance Units. Any Performance Units that remain unvested
after the calculation of the cumulative EPS Goal or the cumulative TSR Goal for
the EPS Performance Period and TSR Performance Period, respectively, or after
distribution in connection with a Change in Control (as set forth in Section 4
above) will be forfeited to and cancelled by the Company. In addition, except as
set forth in Section 4, all unvested Performance Units will be forfeited and
cancelled upon termination of your employment with the Company and its
majority-owned subsidiaries for any reason unless the EPS Performance Period or
TSR Performance Period, a applicable, in which the Performance Units are
eligible to vest has been completed and the Compensation Committee has yet to
certify that the Performance Goals have been achieved.

6.Bookkeeping Account. The Company will record the maximum number of Performance
Units granted to you under this Agreement to a bookkeeping account for you (the
“Performance Unit Account”). Your Performance Unit Account will be adjusted from
time to time for any stock dividends, stock splits, and other transactions in
accordance with Section 9. The Performance Unit Account represents an unsecured
promise of the Company to deliver shares of Common Stock as and when the
Performance Units vest in accordance with this Agreement. Your rights to your
Performance Unit Account will be no greater than that of other general,
unsecured creditors of the Company.

7.Distribution of Shares of Common Stock. When the Performance Units vest either
(i) upon certification by the Compensation Committee of the achievement of one
or both of the Performance Goals at the end of the EPS Performance Period or TSR
Performance Period, a applicable or (ii) in connection with a Change in Control
(as set forth in Section 4 above), the number of shares of Common Stock equal to
such vested Performance Units shall be distributed as soon as practicable after
the date of vesting to you (or your beneficiary(ies) or personal representative,
if you are deceased). Distributions shall be made in shares of Common Stock,
with fractional shares rounded up to the nearest whole share. An amount payable
on a date specified above shall be paid as soon as administratively feasible
after such date. The payment date may be postponed further if calculation of the
amount of the payment is not administratively practicable due to events beyond
your control, and the payment is made in the first calendar year in which the
calculation of the amount of the payment is administratively practicable.

8.Death Beneficiary Designation. You may designate a beneficiary or
beneficiaries (contingently, consecutively or successively) to receive shares of
Common Stock, if you die while Performance Units are held in your Performance
Unit Account, and the Company will distribute upon vesting of the Performance
Units shares of Common Stock equal in number to such vested Performance Units to
your beneficiary(ies).

You may designate a beneficiary or beneficiaries from time to time, and you may
change your designated beneficiary(ies). A beneficiary may be a trust. A
beneficiary designation must be made in writing in a form prescribed by the
Company and delivered to the Company while you are alive. If you do not have a
designated

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beneficiary surviving at the time of your death, any transfer of shares of
Common Stock will be made to your surviving spouse, if any, and if you do not
have a surviving spouse, then to your estate.

9.Adjustments. Subject to Section 4 above, if there is any change in the Common
Stock by reason of stock dividends, split-ups, mergers, consolidations,
reorganizations, combinations or exchanges of shares or the like, the number of
Performance Units then credited to your Performance Unit Account shall be
adjusted appropriately so that the number of Performance Units reflected in your
Performance Unit Account after such an event shall equal the number of shares of
Common Stock a stockholder would own after such an event if the stockholder, at
the time such an event occurred, had owned shares of Common Stock equal to the
number of Performance Units reflected in your Performance Unit Account
immediately before such an event.

10.Limitation on Transfer. Your Performance Units are not transferable by you.
Except as may be required by U.S. federal income tax withholding provisions or
by the tax laws of any state or country, your interests (and the interests of
your beneficiaries, if any) under this Agreement are not subject to the claims
of your creditors and may not be voluntarily or involuntarily sold, transferred,
alienated, assigned, pledged, anticipated, or encumbered. Any attempt to sell,
transfer, alienate, assign, pledge, anticipate, encumber, charge or otherwise
dispose of any right to benefits payable hereunder shall be void and of no force
or effect and shall result in a forfeiture of all affected Performance Units.

11.No Shareholder Rights. You will not have any stockholder rights, such as
rights to vote or to receive dividends or other distributions, with respect to
any Performance Units reflected in your Performance Unit Account until
distribution of shares of Common Stock after vesting of the Performance Units.
You will have only the adjustment rights provided in this Agreement.

12.Securities Law. Shares of Common Stock will not be distributed under this
Agreement if such distribution would violate any U.S. federal or state or
non-U.S. securities laws. The Company may take appropriate action to achieve
compliance with those laws in connection with any distribution of Common Stock
to you.

13.Taxes. The Compensation Committee (as defined in the Plan) may withhold
delivery of certificates for shares of Common Stock until you make satisfactory
arrangements to pay any withholding, transfer or other taxes due with respect to
the vesting or distribution of the Performance Units and the issuance of the
underlying shares of Common Stock. You are responsible for the payment of all
taxes applicable to any income realized upon the distribution of the shares of
Common Stock after vesting of the Performance Units. Unless you provide written
notice to the Company within five days after the vesting of the Performance
Units that you will settle your tax obligation by paying cash, or unless
otherwise determined by the Company in its sole discretion, settlement of your
tax obligation shall be made by the Company by withholding and cancelling shares
of Common Stock that would be otherwise distributable to you, with the fair
market value of such Common Stock for such purposes equal to the closing price
per share of Common Stock as generally reported on the Nasdaq Stock Market (or
such other exchange or market where the Common Stock is trading) on the date of
distribution of the shares of Common Stock . If you elect to settle your tax
obligation by paying cash, and do not make timely payment of your tax
withholding obligation by cash or check by the date of distribution of the
shares of Common Stock, the Company may, in its sole discretion, satisfy your
tax withholding obligation by withholding and cancelling shares of Common Stock
that would be otherwise distributable to you in the manner set forth in this
Section 13.

14.No Right to Continue as an Employee; No Right to Further Grants. This
Agreement does not give you any right to continue as an employee of the Company
or any of its subsidiaries for any period of time or at any rate of
compensation, nor does it interfere with the Company’s or its subsidiaries’
right to determine the terms of your employment.

15.Rules of Construction. This Agreement shall be administered, interpreted, and
construed in a manner consistent with Code section 409A to the extent necessary
to avoid the imposition of additional taxes under Code section 409A(a)(1)(B).
Should any provision of this Agreement be found not to comply with, or otherwise
be exempt from, the provisions of Code section 409A, such provision shall be
modified and given effect (retroactively

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if necessary), in the sole discretion of the Compensation Committee, and without
your consent, in such manner as the Compensation Committee determines to be
necessary or appropriate to comply with, or to effectuate an exemption from,
Code section 409A. In particular, where the time of payment is predicated upon a
termination of employment, termination of employment shall mean a separation
from service as defined in the regulations under section 409A of the Internal
Revenue Code. Such regulations are hereby incorporated by reference where
applicable.

16.Interpretations Binding. The interpretations and determinations of the
Compensation Committee are binding and conclusive. This Agreement is entered
into in Missouri and its terms shall be governed by and interpreted in
accordance with the laws of the State of Missouri without regard to conflict of
law principles.

17.Jurisdiction. Any suit or other legal action to enforce the terms of this
Agreement or any document or agreement referenced herein must be brought in the
St. Louis County, Missouri Circuit Court or (if federal jurisdiction exists) the
U.S. District Court for the Eastern District of Missouri. You agree that venue
and personal jurisdiction are proper in either such court, and waive all
objections to jurisdiction and venue and any defense or claim that either such
forum is not the most convenient forum.

18.Termination of Right to Receive Shares; Recoupment. You understand and agree
that your right to receive and retain the Performance Units granted herein (and
the benefits thereof) is conditioned on your compliance with the terms of this
Agreement and any agreement referenced herein. In the event you violate this
Agreement or any other agreement referenced herein, then in addition to and not
in lieu of any other rights and remedies available to the Company for such
breach, all of which are expressly reserved, the Company may: (i) cancel any
Performance Units that are unvested or vested but not yet issued to you; and
(ii) recover from you any and all common stock issued to you under any
Performance Units, or an amount equal to the value of the same, with such value
being the fair market value of the common stock at the close of business on the
date that the shares were issued under the Performance Units.

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