
<PAGE>
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                       SECURITIES AND EXCHANGE COMMISSION
 
                             WASHINGTON, D.C. 20549
                            ------------------------
 
                                 SCHEDULE 14D-1
 
                             TENDER OFFER STATEMENT
 
                          PURSUANT TO SECTION 14(D)(1)
                     OF THE SECURITIES EXCHANGE ACT OF 1934
 
                                      AND
 
                                  SCHEDULE 13D
 
                   UNDER THE SECURITIES EXCHANGE ACT OF 1934
                            ------------------------
 
                                   CALMAT CO.
 
                           (Name of Subject Company)
 
                          ALB ACQUISITION CORPORATION
 
                            VULCAN MATERIALS COMPANY
 
                                   (Bidders)
                            ------------------------
 
                      COMMON STOCK, PAR VALUE $1 PER SHARE
 
                         (Title of Class of Securities)
 
                                   131271108
 
                     (CUSIP Number of Class of Securities)
                            ------------------------
 
                             WILLIAM F. DENSON, III
                          ALB ACQUISITION CORPORATION
                            VULCAN MATERIALS COMPANY
                              ONE METROPLEX DRIVE
                           BIRMINGHAM, ALABAMA 35209
                                 (205) 877-3204
 
                 (Name, Address and Telephone Number of Person
                Authorized to Receive Notices and Communications
                              on Behalf of Bidder)
 
                                   COPIES TO:
 
                            EDWARD D. HERLIHY, ESQ.
                         WACHTELL, LIPTON, ROSEN & KATZ
                              51 WEST 52ND STREET
                            NEW YORK, NEW YORK 10019
                                 (212) 403-1000
 
                           CALCULATION OF FILING FEE
 
<TABLE>
<CAPTION>
            TRANSACTION VALUATION*                           AMOUNT OF FILING FEE**
<S>                                              <C>
                 $803,299,373                                       $160,660
</TABLE>
 
 *  For purposes of calculating the filing fee only. Based upon 23,797,279
    shares of Common Stock, par value $1.00 per share, of CalMat Co. outstanding
    on November 9, 1998, plus the number of Shares issuable upon exercise of all
    outstanding options.
 
**  The fee, calculated in accordance with Rule 0-11(d) of the Securities
    Exchange Act of 1934, is 1/50th of one percent of the aggregate Transaction
    Valuation.
 
/ /  Check box if any part of the fee is offset as provided by Rule 0-11(a)(2)
     and identify the filing with which the offsetting fee was previously paid.
     Identify the previous filing by registration statement number, or the Form
     or Schedule and date of its filing.
 
<TABLE>
<S>                        <C>              <C>            <C>
Amount Previously Paid:    None             Filing Party:  N/A
Form of Registration No.:  N/A              Date Filed:    N/A
</TABLE>
 
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<PAGE>
CUSIP NO. 131271108                        14D-1 AND 13D
 
<TABLE>
<C>        <S>
   1.      Name of Reporting Person
           S.S. or I.R.S. Identification No. of Above Person
 
           ALB Acquisition Corporation (Pending)
   2.      Check the Appropriate Box if a Member of a Group          (a) / /
 
           (b) /X/
   3.      SEC Use Only
   4.      Sources of Funds
 
           AF
   5.      Check Box if Disclosure of Legal Proceedings is Required Pursuant
           to Items 2(e) or 2(f)  / /
   6.      Citizenship or Place of Organization
 
           Delaware
   7.      Aggregate Amount Beneficially Owned by Each Reporting Person
 
           676,549 shares of common stock, par value $1.00 per share of
           CalMat Co.*
   8.      Check Box if the Aggregate Amount in Row (7) Excludes Certain
           Shares
 
           / /
   9.      Percent of Class Represented by Amount in Row (7)
 
           2.8%
   10.     Type of Reporting Person
 
           CO
</TABLE>
 
*    On November 14, 1998, Vulcan Materials Company ("Parent") entered into
support agreements (the "Support Agreements") with each member of the Board of
Directors of CalMat Co. (the "Company"). Pursuant to the Support Agreements,
upon the terms set forth therein, such stockholders generally have agreed to
tender, in accordance with the terms of the tender offer described in this
statement (the "Offer") 639,549 shares of common stock, par value $1.00 per
share (the "Common Stock"), of the Company, which shares are reflected in Rows 7
and 9 of pages 2 and 3 of this Schedule 14D-1. The Support Agreements are
described in more detail in Section 11 of the Offer to Purchase dated November
20, 1998.
 
                                       2
<PAGE>
CUSIP NO. 131271108                        14D-1 AND 13D
 
<TABLE>
<C>        <S>
   1.      Name of Reporting Person
           S.S. or I.R.S. Identification No. of Above Person
 
           Vulcan Materials Company
           I.R.S. No. 63-0366371
   2.      Check the Appropriate Box if a Member of a Group          (a) / /
 
           (b) / /
   3.      SEC Use Only
   4.      Sources of Funds
 
           WC, BK, OO
   5.      Check Box if Disclosure of Legal Proceedings is Required Pursuant
           to Items 2(e) or 2(f)  / /
   6.      Citizenship or Place of Organization
 
           New Jersey
   7.      Aggregate Amount Beneficially Owned by Each Reporting Person
 
           676,549 shares of Common Stock
   8.      Check Box if the Aggregate Amount in Row (7) Excludes Certain
           Shares
 
           / /
   9.      Percent of Class Represented by Amount in Row (7)
 
           2.8%
   10.     Type of Reporting Person
 
           CO
</TABLE>
 
                                       3
<PAGE>
    This Schedule 14D-1 Tender Offer Statement relates to the offer by ALB
Acquisition Corporation (the "Purchaser"), a Delaware corporation and a
wholly-owned subsidiary of Vulcan Materials Company, a New Jersey corporation
("Parent"), to purchase all outstanding shares of Common Stock, par value $1.00
per share (the "Shares"), of CalMat Co., a Delaware corporation (the "Company"),
and the associated common share purchase rights (the "Rights") issued pursuant
to the Rights Agreement, dated as of September 22, 1987, as amended as of
October 26, 1992, July 22, 1997 and November 14, 1998 between the Company and
First Chicago Trust Company of New York, as Rights Agent (as the same may be
amended, the "Rights Agreement"), at a purchase price of $31.00 per Share (and
associated Right), net to the seller in cash, without interest thereon, upon the
terms and subject to the conditions set forth in the Offer to Purchase and in
the related Letter of Transmittal (which together constitute the "Offer"), which
are annexed to and filed with this Schedule 14D-1 as Exhibits (a)(1) and (a)(2),
respectively. The Purchaser has been formed by Parent in connection with the
Offer and the transactions contemplated thereby. This Schedule 14D-1 is being
filed on behalf of the Purchaser and Parent.
 
ITEM 1. SECURITY AND SUBJECT COMPANY.
 
    (a) The name of the subject company is CalMat Co. The address of its
principal executive offices is 3200 San Fernando Road, Los Angeles, California
90065.
 
    (b) Reference is hereby made to the information set forth in the
"Introduction," Section 1 ("Terms of the Offer") and Section 11 ("Purpose of the
Offer; the Merger Agreement; the Support Agreements; Appraisal Rights; Plans for
the Company; "Going Private" Transactions; the Rights") of the Offer to
Purchase, which is incorporated herein by reference.
 
    (c) Reference is hereby made to the information set forth in Section 6
("Price Range of the Shares; Dividends") of the Offer to Purchase, which is
incorporated herein by reference.
 
ITEM 2. IDENTITY AND BACKGROUND.
 
    (a)-(d) This Statement is being filed on behalf of Parent and the Purchaser
for purposes of the Schedule 14D-1. Reference is hereby made to the information
set forth in the "Introduction," Section 9 ("Certain Information Concerning
Parent and the Purchaser") and Schedule I (Directors and Executive Officers of
Parent and the Purchaser) of the Offer to Purchase, which is incorporated herein
by reference.
 
    (e)-(f) During the last five years, neither Parent nor the Purchaser, nor,
to the best of their knowledge, any of their respective executive officers and
directors listed in Schedule I (Directors and Executive Officers of Parent and
the Purchaser) of the Offer to Purchase, which is incorporated herein by
reference, has been convicted in a criminal proceeding (excluding traffic
violations or similar misdemeanors) or was a party to a civil proceeding of a
judicial or administrative body of competent jurisdiction and as a result of
such proceeding was or is subject to a judgment, decree or final order enjoining
future violations of, or prohibiting activities subject to, Federal or State
securities laws or finding any violation of such laws.
 
    (g) Reference is hereby made to the information set forth in Schedule I
(Directors and Executive Officers of Parent and the Purchaser) of the Offer to
Purchase, which is incorporated herein by reference.
 
ITEM 3. PAST CONTACTS, TRANSACTIONS OR NEGOTIATIONS WITH THE SUBJECT COMPANY.
 
    (a)-(b) Reference is hereby made to the information set forth in the
"Introduction," Section 9 ("Certain Information Concerning Parent and the
Purchaser"), Section 10 ("Background of the Offer; Contacts with the Company")
and Section 11 ("Purpose of the Offer; the Merger Agreement; the
 
                                       4
<PAGE>
Support Agreements; Appraisal Rights; Plans for the Company; "Going Private"
Transactions; the Rights") of the Offer to Purchase, which is incorporated
herein by reference.
 
ITEM 4. SOURCE AND AMOUNT OF FUNDS OR OTHER CONSIDERATION.
 
    (a)-(b) Reference is made to the information set forth in Section 12
("Source and Amount of Funds") of the Offer to Purchase, which is incorporated
herein by reference.
 
    (c) Not applicable.
 
ITEM 5. PURPOSE OF THE TENDER OFFER AND PLANS OR PROPOSALS OF THE BIDDER.
 
    (a)-(g) Reference is hereby made to the information set forth in the
"Introduction," Section 7 ("Possible Effects of the Offer on the Market for the
Shares; NYSE Listing; Exchange Act Registration; Margin Regulations"), Section
10 ("Background of the Offer; Contacts with the Company"), Section 11 ("Purpose
of the Offer; the Merger Agreement; the Support Agreements; Appraisal Rights;
Plans for the Company; "Going Private" Transactions; the Rights") and Section 13
("Dividends and Distributions") of the Offer to Purchase, which is incorporated
herein by reference.
 
ITEM 6. INTEREST IN SECURITIES OF THE SUBJECT COMPANY.
 
    (a)-(b) Reference is hereby made to the information set forth in Section 9
("Certain Information Concerning Parent and the Purchaser") and Schedule I
(Directors and Executive Officers of Parent and the Purchaser) of the Offer to
Purchase, which is incorporated herein by reference.
 
ITEM 7. CONTRACTS, ARRANGEMENTS, UNDERSTANDINGS OR RELATIONSHIPS WITH RESPECT TO
        THE SUBJECT COMPANY'S SECURITIES.
 
    Reference is hereby made to the information set forth in the "Introduction,"
Section 9 ("Certain Information Concerning Parent and the Purchaser"), Section
10 ("Background of the Offer; Contacts with the Company"), Section 11 ("Purpose
of the Offer; the Merger Agreement; the Support Agreements; Appraisal Rights;
Plans for the Company; "Going Private" Transactions; the Rights") and Section 15
("Certain Legal Matters; Required Regulatory Approvals") of the Offer to
Purchase, which is incorporated herein by reference.
 
ITEM 8. PERSONS RETAINED, EMPLOYED OR TO BE COMPENSATED.
 
    Reference is hereby made to the information set forth in Section 16
("Certain Fees and Expenses") of the Offer to Purchase, which is incorporated
herein by reference.
 
ITEM 9. FINANCIAL STATEMENTS OF CERTAIN BIDDERS.
 
    Reference is hereby made to the information set forth in Section 9 ("Certain
Information Concerning Parent and the Purchaser") of the Offer to Purchase,
which is incorporated herein by reference.
 
ITEM 10. ADDITIONAL INFORMATION.
 
    (a) Reference is hereby made to the information set forth in the
"Introduction," Section 10 ("Background of the Offer; Contacts with the
Company") and Section 11 ("Purpose of the Offer; the Merger Agreement; the
Support Agreements; Appraisal Rights; Plans for the Company; "Going Private"
Transactions; the Rights") of the Offer to Purchase, which is incorporated
herein by reference.
 
    (b)-(c) Reference is hereby made to the information set forth in the
"Introduction," Section 11 ("Purpose of the Offer; the Merger Agreement; the
Support Agreements; Appraisal Rights; Plans for the
 
                                       5
<PAGE>
Company; "Going Private" Transactions; the Rights") and Section 15 ("Certain
Legal Matters; Required Regulatory Approvals") of the Offer to Purchase, which
is incorporated herein by reference.
 
    (d) Reference is hereby made to the information set forth in Section 7
("Possible Effects of the Offer on the Market for the Shares; NYSE Listing;
Exchange Act Registration; Margin Regulations") of the Offer to Purchase, which
is incorporated herein by reference.
 
    (e) Reference is hereby made to the information set forth in Section 15
("Certain Legal Matters; Required Regulatory Approvals") of the Offer to
Purchase, which is incorporated herein by reference.
 
    (f) Reference is hereby made to the entire texts of the Offer to Purchase
and the related Letter of Transmittal, which are incorporated herein by
reference.
 
ITEM 11. MATERIAL TO BE FILED AS EXHIBITS.
 
<TABLE>
<C>        <S>
   (a)(1)  --Offer to Purchase, dated November 20, 1998.
   (a)(2)  --Letter of Transmittal.
   (a)(3)  --Letter to Brokers, Dealers, Commercial Banks, Trust Companies and Nominees.
   (a)(4)  --Letter to Clients for Use by Brokers, Dealers, Commercial Banks, Trust Companies
             and Nominees.
   (a)(5)  --Notice of Guaranteed Delivery.
   (a)(6)  --Guidelines for Certification of Taxpayer Identification Number on Substitute Form
             W-9.
   (a)(7)  --Text of press release issued by Parent and the Company on November 16, 1998.
   (a)(8)  --Form of Summary Advertisement, dated November 20, 1998.
   (c)(1)  --Agreement and Plan of Merger, dated as of November 14, 1998, by and among the
             Company, the Purchaser and Parent.
   (c)(2)  --Form of Support Agreement entered into between Parent and John C. Argue, Arthur
             Brown, Denis R. Brown, Harry M. Conger, Rayburn S. Dezember, A. Frederick
             Gerstell, Richard A. Grant, Jr., Edward A. Landry, Thomas L. Lee, Thomas M.
             Linden, Georgia R. Nelson and Stuart T. Peeler.
   (c)(3)  --Confidentiality Agreement, dated as of September 24, 1998, between the Company and
             Parent.
    (d)    --Not applicable.
    (e)    --Not applicable.
    (f)    --Not applicable.
</TABLE>
 
                                       6
<PAGE>
                                   SIGNATURE
 
    After due inquiry and to the best of my knowledge and belief, I certify that
the information set forth in this statement is true, complete and correct.
 
Dated: November 20, 1998
 
<TABLE>
<S>                             <C>  <C>
                                VULCAN MATERIALS COMPANY
 
                                By:  /s/ DONALD M. JAMES
                                     -----------------------------------------
                                     Name: Donald M. James
                                     Title: Chairman and Chief Executive
                                     Officer
 
                                ALB ACQUISITION CORPORATION
 
                                By:  /s/ DONALD M. JAMES
                                     -----------------------------------------
                                     Name: Donald M. James
                                     Title: Chairman and Chief Executive
                                     Officer
</TABLE>
 
                                       7
<PAGE>
                                 EXHIBIT INDEX
 
<TABLE>
<CAPTION>
 EXHIBIT
   NO.                                          DESCRIPTION
----------  -----------------------------------------------------------------------------------
<C>         <S>
    (a)(1)  --Offer to Purchase, dated November 20, 1998.
    (a)(2)  --Letter of Transmittal.
    (a)(3)  --Letter to Brokers, Dealers, Commercial Banks, Trust Companies and Nominees.
    (a)(4)  --Letter to Clients for Use by Brokers, Dealers, Commercial Banks, Trust Companies
              and Nominees.
    (a)(5)  --Notice of Guaranteed Delivery.
    (a)(6)  --Guidelines for Certification of Taxpayer Identification Number on Substitute Form
              W-9.
    (a)(7)  --Text of press release issued by Parent and the Company on November 16, 1998.
    (a)(8)  --Form of Summary Advertisement, dated November 20, 1998.
    (c)(1)  --Agreement and Plan of Merger, dated as of November 14, 1998, by and among the
              Company, the Purchaser and Parent.
    (c)(2)  --Form of Support Agreement entered into between Parent and John C. Argue, Arthur
              Brown, Denis R. Brown, Harry M. Conger, Rayburn S. Dezember, A. Frederick
              Gerstell, Richard A. Grant, Jr., Edward A. Landry, Thomas L. Lee, Thomas M.
              Linden, Georgia R. Nelson and Stuart T. Peeler.
    (c)(3)  --Confidentiality Agreement, dated as of September 24, 1998, between the Company
              and Parent.
     (d)    --Not applicable.
     (e)    --Not applicable.
     (f)    --Not applicable.
</TABLE>
 
                                       8
