<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2018-11-01</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

    <issuer>
        <issuerCik>0001739445</issuerCik>
        <issuerName>Arcosa, Inc.</issuerName>
        <issuerTradingSymbol>NYSE/ACA</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000099780</rptOwnerCik>
            <rptOwnerName>TRINITY INDUSTRIES INC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2525 N. STEMMONS FREEWAY</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>DALLAS</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>75207</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2018-11-01</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>100</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">The transaction reported on this Form 4 relates to the distribution to the stockholders of Trinity Industries, Inc. (&quot;TRN&quot;) of shares of common stock of Arcosa, Inc. (&quot;ACA&quot;) held by TRN, effective as of November 1, 2018 (the &quot;Distribution&quot;). To effect the Distribution, the issued and outstanding common stock of ACA, consisting of 100 shares of common stock prior to the Distribution, was recapitalized into 48,765,628 shares of ACA's common stock and distributed, by means of a pro rata dividend, to the holders of record of TRN's common stock as of October 17, 2018 (other than fractional shares, which TRN's stockholders received in cash in lieu of the fractional shares of ACA common stock that such stockholders would have received as a result of the application of the distribution ratio).</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ James E Perry, Senior Vice President &amp; Chief Financial Officer</signatureName>
        <signatureDate>2018-11-01</signatureDate>
    </ownerSignature>
</ownershipDocument>
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X0306
4
2018-11-01
1
0001739445
Arcosa, Inc.
NYSE/ACA
0000099780
TRINITY INDUSTRIES INC
2525 N. STEMMONS FREEWAY
DALLAS
TX
75207
0
0
1
0
Common Stock
2018-11-01
4
J
0
100
0
D
0
D
The transaction reported on this Form 4 relates to the distribution to the stockholders of Trinity Industries, Inc. ("TRN") of shares of common stock of Arcosa, Inc. ("ACA") held by TRN, effective as of November 1, 2018 (the "Distribution"). To effect the Distribution, the issued and outstanding common stock of ACA, consisting of 100 shares of common stock prior to the Distribution, was recapitalized into 48,765,628 shares of ACA's common stock and distributed, by means of a pro rata dividend, to the holders of record of TRN's common stock as of October 17, 2018 (other than fractional shares, which TRN's stockholders received in cash in lieu of the fractional shares of ACA common stock that such stockholders would have received as a result of the application of the distribution ratio).
/s/ James E Perry, Senior Vice President & Chief Financial Officer
2018-11-01