<simpleType name="HeadPreparationEnumType">
  <restriction base="string">
    <enumeration value="cut_and_ground">
      <annotation>
        <documentation>Cut down to sound concrete and the test surface ground smooth.</documentation>
      </annotation>
    </enumeration>
    <enumeration value="cut">
      <annotation>
        <documentation>Cut down to sound concrete; the test surface not ground.</documentation>
      </annotation>
    </enumeration>
    <enumeration value="ground">
      <annotation>
        <documentation>The test surface ground smooth without cutting.</documentation>
      </annotation>
    </enumeration>
    <enumeration value="none">
      <annotation>
        <documentation>Tested on the head as found, without preparation.</documentation>
      </annotation>
    </enumeration>
  </restriction>
</simpleType>