<SUBMISSION>
<ACCESSION-NUMBER>0001140361-08-023093
<TYPE>4
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20081009
<FILING-DATE>20081014
<DATE-OF-FILING-DATE-CHANGE>20081014
<ISSUER>
<COMPANY-DATA>
<CONFORMED-NAME>ASTEC INDUSTRIES INC
<CIK>0000792987
<ASSIGNED-SIC>3531
<IRS-NUMBER>620873631
<STATE-OF-INCORPORATION>TN
<FISCAL-YEAR-END>0723
</COMPANY-DATA>
<BUSINESS-ADDRESS>
<STREET1>1725 SHEPHERD ROAD
<CITY>CHATTANOOGA
<STATE>TN
<ZIP>37421
<PHONE>4238995898
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>1725 SHEPHERD ROAD
<CITY>CHATTANOOGA
<STATE>TN
<ZIP>37421
</MAIL-ADDRESS>
</ISSUER>
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>GONIGAM TIMOTHY D
<CIK>0001182952
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4
<ACT>34
<FILE-NUMBER>001-11595
<FILM-NUMBER>081120298
</FILING-VALUES>
<BUSINESS-ADDRESS>
<STREET1>4101 JEROME AVENUE
<CITY>CHATTANOOGA
<STATE>TN
<ZIP>87407
<PHONE>423-899-5898
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>1725 SHEPHERD RD
<CITY>CHATTANOOGA
<STATE>TN
<ZIP>37421
</MAIL-ADDRESS>
</REPORTING-OWNER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc1.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2008-10-09</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000792987</issuerCik>
        <issuerName>ASTEC INDUSTRIES INC</issuerName>
        <issuerTradingSymbol>ASTE</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001182952</rptOwnerCik>
            <rptOwnerName>GONIGAM TIMOTHY D</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1725 SHEPHERD RD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>CHATTANOOGA</rptOwnerCity>
            <rptOwnerState>TN</rptOwnerState>
            <rptOwnerZipCode>37421</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>President-Astec Mobile Screens</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>216.3205</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>by 401(k) Plan</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Phantom Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F2"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2008-10-09</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>129.9033</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>22.7092</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F2"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>129.9033</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2550.963</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Shares owned in reporting person's 401(k) account are based upon a Plan statement date 10/9/08.</footnote>
        <footnote id="F2">Reported transaction represents Astec's quarterly contribution to the reporting person's SERP which was used to purchase Astec stock.  Funds held in the SERP are payable in cash following the reporting person's termination of employment from Astec.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Robert Taylor, attorney in fact for Timothy Gonigam</signatureName>
        <signatureDate>2008-10-14</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SUBMISSION>
