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Historic Preservation - Technical Procedures

Spectitle:

Removing Creosote Stains From Concrete

Procedure code:

0371013R

Source:

Hstrc Concrete: Investigation & Rpr/Pre-Conf Training - 1989

Division:

Concrete

Section:

Concrete Cleaning

Last Modified:

02/24/2012

Details:

Removing Creosote Stains From Concrete



REMOVING CREOSOTE STAINS FROM CONCRETE


THE CLEANING OR REMOVAL OF STAINS FROM CONCRETE MAY INVOLVE THE
USE OF LIQUIDS, DETERGENTS OR SOLVENTS WHICH MAY RUN OFF ON
ADJACENT MATERIAL, DISCOLOR THE CONCRETE OR DRIVE THE STAINS DEEPER
INTO POROUS CONCRETE.  USE THE PRODUCTS AND TECHNIQUES DESCRIBED
HERE ONLY FOR THE COMBINATIONS OF DIRT/STAIN AND CONCRETE SPECIFIED.


PART 1---GENERAL

1.01 SUMMARY

    A.   This procedure includes guidance on removing creosote
         staining from concrete using a poultice containing
         benzene.

    B.   Safety Precautions:

         1.   DO NOT save unused portions of stain-removal
              materials.

         2.   DO NOT store any chemicals in unmarked containers.

         3.   EXCELLENT VENTILATION MUST BE PROVIDED WHEREVER ANY
              SOLVENT IS USED.  USE RESPIRATORS WITH SOLVENT
              FILTERS.

              NOTE:  SOME OF THE SOLVENTS LISTED ARE KNOWN
              CARCINOGENS AND MAY BE BANNED IN SOME STATES.

         4.   No use of organic solvents indoors should be
              allowed without substantial air movement.  Use only
              spark-proof fans near operations involving
              flammable liquids.

         5.   Provide adequate clothing and protective gear where
              the chemicals are indicated to be dangerous.

         6.   Have available antidote and accident treatment
              chemicals where noted.

    C.   See 01100-07-S for general project guidelines to be
         reviewed along with this procedure.  These guidelines
         cover the following sections:

         1.   Safety Precautions

         2.   Historic Structures Precautions

         3.   Submittals

         4.   Quality Assurance

         5.   Delivery, Storage and Handling

         6.   Project/Site Conditions

         7.   Sequencing and Scheduling

         8.   General Protection (Surface and Surrounding)

         These guidelines should be reviewed prior to performing
         this procedure and should be followed, when applicable,
         along with recommendations from the Regional Historic
         Preservation Officer (RHPO).

    D.   For additional information on poulticing, see 04455-02-R.


PART 2---PRODUCTS

2.01 MATERIALS

    NOTE:  Chemical products are sometimes sold under a common
    name.  This usually means that the substance is not as pure as
    the same chemical sold under its chemical name.  The grade of
    purity of common name substances, however, is usually adequate
    for stain removal work, and these products should be purchased
    when available, as they tend to be less expensive.  Common
    names are indicated below by an asterisk (*).

    A.   Benzene (C6H6):

         1.   A colorless, volatile, flammable, toxic, liquid,
              aromatic hydrocarbon used in organic synthesis, as
              a solvent and as a motor fuel.

         2.   Other chemical or common names include Benzol;
              Benzole; Phene; Phenyl hydride; Coal naphtha*;
              Motor benzol*.

         3.   Potential Hazards:  FLAMMABLE.

         4.   Available from automotive supply distributor,
              chemical supply house, dry cleaning supply
              distributor, hardware store or paint store.

         5.   Benzene and benzine should not be confused.
              Benzene is a distinct chemical compound obtained
              from coal tar.  Benzine is a mixture of aromatic
              hydrocarbons of similar boiling points derived from
              petroleum.

    B.   Filler material such as hydrated lime, talc or whiting

    C.   Mineral water

    D.   Clean dry towels for blotting the area after treatment

    E.   Scouring powder

    F.   Clean, potable water

2.02 EQUIPMENT

    A.   Glass or ceramic container for mixing the solution

    B.   Wooden utensil for stirring the ingredients

    C.   Wood or plastic spatula

    D.   Stiff bristle brushes (non-metallic)


PART 3---EXECUTION

3.01 PREPARATION

    A.   Protection:

         1.   Provide adequate wash solutions (i.e. water, soap
              and towels) before starting the job.

         2.   Whenever acid is used, the surface should be
              thoroughly rinsed with water as soon as its action
              has been adequate.  Otherwise it will continue
              etching the concrete even though the stain is gone.

3.02 ERECTION, INSTALLATION, APPLICATION

    NOTE:  DO NOT TRY MORE THAN ONE TREATMENT ON A GIVEN AREA
    UNLESS THE CHEMICALS USED FROM PRIOR TREATMENT HAVE BEEN
    WASHED AWAY.

    A.   Mix a poultice by selecting the quantity of hydrated
         lime, powdered talc or whiting needed to cover the
         affected area.  Add Benzene and mix to form a thick
         paste.

    B.   Thoroughly wet the concrete surface to be treated with
         clean, clear water.

    C.   Apply the poultice mixture to the stained area using a
         wood or plastic spatula and allow to dry.  Be sure to
         spread the poultice well beyond the stained area.  The
         liquid portion of the paste will migrates into the
         concrete where it will dissolve some of the staining
         material.  Then the liquid will gradually move back
         beyond the concrete surface and into the poultice, where
         it will evaporate, leaving the dissolved staining
         material in the poultice.

    D.   When the poultice has dried, brush or scrape it off with
         a wooden scraper.  

    E.   Using a stiff bristle brush, scrub the surface with
         scouring powder and clean water to remove any residual
         staining.

    F.   Thoroughly rinse the area with clean, clear water and
         allow to dry.

    G.   Repeat the process as necessary to sufficiently remove
         the stain.

                         END OF SECTION