<SUBMISSION>
<ACCESSION-NUMBER>0001140361-08-025035
<TYPE>4
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20081112
<FILING-DATE>20081112
<DATE-OF-FILING-DATE-CHANGE>20081112
<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>SANSOM WILLIAM B
<CIK>0001084492
<ASSIGNED-SIC>1400
<STATE-OF-INCORPORATION>NC
<FISCAL-YEAR-END>1231
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4
<ACT>34
<FILE-NUMBER>001-11595
<FILM-NUMBER>081179009
</FILING-VALUES>
<BUSINESS-ADDRESS>
<STREET1>4101 JEROME AVE
<CITY>CHATTANOOGA
<STATE>TN
<ZIP>37407
<PHONE>4238674210
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>MARTIN MARIETTA MATERIALS INC
<STREET2>2710 WYCLIFF ROAD
<CITY>RALEIGH
<STATE>NC
<ZIP>27607
</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>2008-11-12</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001084492</rptOwnerCik>
            <rptOwnerName>SANSOM WILLIAM B</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>MARTIN MARIETTA MATERIALS, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>2710 WYCLIFF ROAD</rptOwnerStreet2>
            <rptOwnerCity>RALEIGH</rptOwnerCity>
            <rptOwnerState>NC</rptOwnerState>
            <rptOwnerZipCode>27607</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-11-12</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>289</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>24.25</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2214</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>Stock Options</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F2"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F2"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>13721</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>13721</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Shares were issued in payment of the reporting person's quarterly Director fee retainer.</footnote>
        <footnote id="F2">Option prices and dates have been previously reported for stock options currently outstanding.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Robert Taylor, attorney in fact for William B. Sansom</signatureName>
        <signatureDate>2008-11-12</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SUBMISSION>
