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PROTECTION & PRESERVATION OF ASPHALT SURFACES AN INTRODUCTION TO SEALCOATING Girish C. Dubey S.T.A.R., INC. MARCH, 2003.

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Presentation on theme: "PROTECTION & PRESERVATION OF ASPHALT SURFACES AN INTRODUCTION TO SEALCOATING Girish C. Dubey S.T.A.R., INC. MARCH, 2003."— Presentation transcript:

1 PROTECTION & PRESERVATION OF ASPHALT SURFACES AN INTRODUCTION TO SEALCOATING Girish C. Dubey S.T.A.R., INC. MARCH, 2003

2 OBJECTIVES 1. To understand Asphalt Pavements, their;  Basic construction and make up,  Strengths and weaknesses, 2. Why they have to be protected ? 3. Which types of pavements can be protected? 4. How can they be protected ? 5. Overall Savings and value to the property owner. Concept Of SEALCOATINGS

3 ASPHALT PAVEMENT DEFINITION PAVEMENT The solid floor of any construction that carries traffic;  VEHICULAR : High Traffic :Highways, Roads, Streets, Low traffic : Airport runways, aprons, parking lots, driveways, service stations..  PEDESTRIAN: Walkways.  CONSTRUCTION The earth is removed and - Filled with large aggregates (gravel, rocks, limestone- Base course - Filled with smaller aggregates- Sub-base course - Covered with hot molten asphalt (5-10% By weight) mixed with finer aggregates- top course. THIS TOP LAYER, SO TO SPEAK, IS THE " ROOF OF THE PAVEMENT". TOP COURSE (ASPHALT MIX) SUB-BASE COURSE BASE COURSE THE CONSTRUCTION VARIES WITH THE TRAFFIC LOAD REQUIREMENTS.

4 A. PRIOR HISTORY OF ROAD CONSTRUCTION: Constructed with Clay, Limestone, Rocks Functional but severely damaged by rain: The aggregates absorbed water, became soft and lost their strength to carry loads. Roads were destroyed in no time. B. ASPHALT AS A PAVING MATERIAL- Used since 18th. century A by-product of petroleum refining process was plentiful and had excellent;  Adhesive (Gluing) properties,  Water repellency- will not let water penetrate the pavement and damage it.  Flexibility- Pavement surface will flex under traffic without cracking. ASPHALT KEPT WATER OUT OF THE PAVEMENTS, KEEPING THE BASE DRY AND FUNCTIONAL Roads were destroyed in no time

5 WHAT IS ASPHALT IT IS A BY-PRODUCT OF PETROLEUM REFINING PROCESS. CRUDE PETROLEUM - ORIGINATED FROM THE DECAY OF MARINE LIFE OVER MILLIONS OF YEARS. C RUDE PETROLEUM REFINING PROCESS (REMOVES LIGHTER FRACTIONS SOLVENTS, GASOLINE, OILS, GREASE..) RESIDUE : ASPHALT -CHEAP, PLENTIFUL IT IS A VERY COMPLEX MIXTURE OF OVER 5000 COMPOUNDS. ASPHALT AS A PAVING MATERIAL SHORTCOMINGS 1. DETERIORATES UNDER SUN'S ULTRAVIOLET RAYS 2. DISSOLVED BY PETROCHEMICALS (GASOLINE, OILS, FATS, GREASE ETC.) 3. ATTACKED BY CHEMICALS, DEICING SALTS ETC.

6 WHY ??? ATTACKED BY THE ULTRAVIOLET RAYS AND CHEMICALS BECAUSE A MAJORITY OF THE COMPOUNDS PRESENT IN ASPHALT ARE NOT STABLE. THEY HAVE ; OPEN CHAIN STRUCTURE (ALIPHATIC) WITH SITES OF UNSATURATION (DOUBLE AND TRIPLE BONDS) O H H O H H H H H H H H H H H HO C C C C C C C C C C C C C C C H H H H H H H H H H ATTACK ASPHALTIC COMPOUNDS ARE: ATTACKED AT THE SITES OF UNSATURATION THE RESULTING PRODUCTS: DO NOT POSSESS ANY OF THE PROPERTIES OF THE ORIGINAL ASPHALT MOLECULES. DISSOLVED BY PETROCHEMICALS (GASOLINE, OILS, FATS, GREASE ETC..) - SAME ORIGIN, SIMILAR MOLECULAR STRUCTURE. - NATURAL AFFINITY, THEY COEXISTED IN NATURE OVER MILLION OF YEARS. LIKE DISSOLVES THE LIKE.

7 ASPHALT PAVEMENTS BREAKDOWN THE TOP LAYER (UNDER THE ELEMENTS OF WEATHER, PETROCHEMICALS ETC. ) ASPHALT BINDER BREAKS DOWN (GLUING PROPERTIES ARE LOST) AGGREGATES COME UNGLUED, START RAVELING SURFACE CRACKS DEVELOP (WATER SEEPS IN, STARTS DAMAGING THE BASE) CRACKS WIDEN (FURTHER DAMAGE BY WATER) BASE AND SUBBASE COURSES ARE DAMAGED (LOAD CARRYING CAPACITY IS LOST) END OF THE PAVEMENT FRESH OVERLAY NEEDED IN 6-7

8 WHY PROTECT??? SAVE YOUR MAJOR INVESTMENT ENHANCE THE VALUE OF YOUR PROPERTY ALL PAVEMENTS DO NOT NEED PROTECTION NOT NEEDED (TRAFFIC BEARING- HIGHWAYS, ROADS, STREETS) THE ADVANTAGE THE ROLLING TRAFFIC BRINGS UP THE FRESH LAYERS OF ASPHALT CONTINUOUSLY. DETERIORATION IS NOT LOCALIZED TO THE TOP SURFACES. DESPERATELY NEEDED LOW TRAFFIC, NON-TRAFFIC BEARING PAVEMENTS: AIRPORT RUNWAYS APRONS, PARKING LOTS, SERVICE STATIONS, DRIVEWAYS, ALKWAYS.. DO NOT HAVE THE ADVANTAGE OF THE LIFE GIVING ROLLING TRAFFIC. TOP LAYERS ARE UNDER CONTINUOUS ATTACK BY ULTRAVIOLET, GASOLINE, OILS, CHEMICALS ETC.

9 HOW TO PROTECT ASPHALT PAVEMENTS SEALCOAT !!!! APPLY A COATING THAT WILL : -NOT BE ATTACKED BY THE SAME ELEMENTS THAT DESTROY ASPHALT - FORM A BARRIER COAT IN BETWEEN ASPHALT SURFACE AND THE ELEMENTS. - KEEP THE EXCELLENT PROPERTIES OF ASPHALT " SEALED IN " THE PAVEMENT AND "SEAL OUT" THE DESTRUCTIVE ELEMENTS. DESTRUCTIVE ELEMENTS "SEALED OUT" ULTRAVOILT (UV) RADIATIONS SOLVENTS WATER FUEL SEALCOATING ASPHALT PROPERTIES "SEALED IN" SUCH COATINGS ARE ALSO, RIGHTFULLY CALLED "SEALCOATINGS”

10 REFINED TAR (MATERIAL OF CHOICE) BECAUSE: REFINED TAR HAS EXCELLENT resistance to: Ultraviolet Radiation PETROCHEMICALS, GASOLINE, OILS, FAT DEICING SALTS & CHEMICALS REFINED TAR IS A VERY COMPLEX MIXTURE OF (>5000) VERY STABLE CLOSED RING, AROMATIC COMPOUNDS ORIGIN- ENTIRELY DIFFERENT THAN ASPHALT. ASPHALT- DECAY OF MARINE LIFE REFINED TAR IS DERIVED FROM COAL COAL- ORIGINATES FROM THE DECAY OF PLANT LIFE (FORESTS, BOGS, VEGETATION..) COALCOKE (FUEL FOR STEEL MILLS) DISTILLATES, REFINED TAR FURTHER DISTILLATION REFINED TAR CHEMISTRIES OF PLANTS ARE QUITE DIFFERENT TO THOSE OF MARINE LIFE, THEREFORE, THE DIFFERENCES IN THE PROPERTIES OF THEIR DERIVATIVES.

11 SEALCOATINGS COMPOSITION SEALCOATINGS ARE WATER- BASED COATINGS. FORMULATED BY DISPERSING: -REFINED TAR -WATER -CLAYS AND FILLERS -SURFACTANTS/ EMULSIFIERS ALSO CALLED REFINED TAR PITCH EMULSIONS (C.T.P.E.), THEY ARE; - EASY TO APPLY (BRUSH, SQUEEGEE, SPRAY) - EASY TO HANDLE AND STORE, - EASE OF WATER CLEAN UP OF TOOLS, - NO SOLVENT FUMES OR HAZARDS OF SOLVENT BASED COATINGS APPROVED BY U.S. - FEDERAL AVIATION ADMINISTRATION: P-625, 627,628 U.S. GOVERNMENTAL SERVICES ADMIN. LOCAL AND STATE GOVERNMENTS

12 APPLICATION PAVEMENT PREPARATION: GENERAL GUIDELINES PRIOR TO SEALCOATING: 1. A. NEW PAVEMENTS: ALLOW TO CURE (OXIDIZE) TO RID OF SURFACE OILS, PERFORM WATER BREAK TEST- NO SURFACE BEADING B. OLD PAVEMENTS: REPAIR THE DAMAGED AREAS; SEAL ALL CRACKS, REMOVE DAMAGED AREAS- REPATCH WITH FRESH ASPHALT MIX, 2. CLEAN THE PAVEMENT: REMOVE DIRT AND DEBRIS, SCRAPE OIL SPOTS AND PRIME WITH OIL SPOT PRIMER. 3. APPLY SEALCOATING MIX: FOG THE SURFACE WITH A MIST OF WATER IF SURFACE TEMPERATURES ARE ABOVE FORTY (40) DEGREES CELSIUS. APPLY THE FIRST COAT WITH A RUBBER SQUEEGEE, FOLLOWED BY A BRUSH FOR THE 2ND. COAT. SPRAY APPLICATION ACCEPTABLE IF APPLIED BY AN EXPERIENCED APPLICATOR. 4. FOLLOW SAFE HANDLING PROCEDURES DO NOT APPLY BELOW 50° F RAIN IN THE FORECAST

13 MIX DESIGNS SEALCOATING IS NEVER APPLIED IN ITS CONCENTRATED FORM GENERALLY MIXED WITH; WATER, SILICA SAND WORKABLE CONSISTENCY DESIRED PROPERTIES STANDARD SYSTEM (A 2-COAT APPLICATION SYSTEM) Two coat gal/sq. yard. IST COAT : GAL OF SEALER/ SQ. YARD IIND. COAT : GAL OF SEALER/ SQ. YARD MIX DESIGN SEALCOATING (CONC)100 GAL WATER (30% BY VOL. OF THE SEALER) 30 GAL SILICA SAND (AVG MESH), LB TOTAL 145 GAL.

14 BENEFITS OF SEALCOATING THROUGH REGULAR MAINTENANCE PROGRAMS: 1. SAVES MONEY FOR THE OWNER : PAVEMENT LIFE CAN BE EXTENDED BY APPROX. 300% 2. PROTECTS AND PRESERVES THE ASPHALT PAVEMENT 3. ENHANCES BUSINESS IMAGE THE BLACK/ DARK SLATE COLOR OF THE SEALCOATING WILL NOT FADE. ASPHALT TURNS GRAY IN NO TIME. 4. CLEANING BECOMES EASIER. DIRT AND DEBRIS ARE EASILY WASHED OFF BY RAIN. 5. TRAFFIC MARKINGS LAST LONGER.

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