Page 595 - Handbook of Thermal Analysis of Construction Materials
P. 595

562                    Chapter 13 - Organic Construction Materials


                                     Asphalt can be considered as a colloidal system, similar to petro-
                              leum, with the lighter molecules removed. The carbon types in petroleum
                              can be classified as paraffinic (C ), naphthenic (C ), and aromatic (C ). As
                                                          P
                                                                         N
                                                                                         A
                              fractions become heavier, the proportion of C , C , and C  becomes
                                                                         P   N       A
                              larger. [31]
                                     The physical properties of asphalt are directly related to the
                              quantity of the dispersed phase (asphaltenes); the size of the micellar
                              structures, which depends upon the degree of adsorption of resins; the
                              nature of the dispersion medium; and maltenes (oils and resins). In heavier
                              fractions of petroleum, single molecules contain C , C , and C  portions.
                                                                          P
                                                                              N
                                                                                     A
                              The aromatic protons near the aromatic ring system can participate in
                              electrophilic reactions, such as nitration, sulfonation, halogenation, and
                              others. The interaction between the molecules will determine the chemical
                              properties of asphalt.
                                     The rheological properties of asphalt are concerned with the study
                              of physical or mechanical stability of the colloidal system under varying
                              conditions of time, temperature, pressure, load or stress. Hence, a study of
                              its rheological properties is essential for practical applications such as
                              pavement, roofing, coating, and other types of applications. [31]
                                     Asphalt products have a variety of applications in the construction
                              industry:
                                     • Buildings (conduit, insulation, paint composition, pa-
                                        pers, roofing membranes, shingles)
                                     • Roofing (building papers, BUR adhesive, felts, primers,
                                        caulking compounds, cement waterproofing compounds,
                                        laminated roofing, shingles, liquid roof coatings, plastic
                                        cements)

                                     • Floors (damp-proofing and waterproofing, tiles, cover-
                                        ings, insulating fabrics, step treads)
                                     • Walls, siding, ceilings (acoustical blocks, felts, bricks,
                                        brick siding, building blocks, masonry coatings, plaster
                                        boards, putty, asphalt, soundproofing, stucco base)
                                     • Paints, varnishes (acid-proof enamel, acid-resistant coat-
                                        ings, anti-oxidants and solvents, boat deck sealing com-
                                        pound, lacquers)
                                     • Electrical products (tapes, wire coatings, junction box
                                        compounds, molded conduits)
   590   591   592   593   594   595   596   597   598   599   600