BS 6925:1988 download free.Specification for Mastic asphalt for building and civil engineering ( limestone aggregate ).
1 Scope
BS 6925 specifies requirements for roofing, tanking and flooring grades of mastic asphalt for building and civil engineering purposes, composed of ground limestone, coarse aggregate and pigment if required, incorporated with asphaltic cements.
NOTE The titles of the publications referred to in BS 6925 are listed on the inside back cover.
2 Definitions
For the purposes of BS 6925 the following definitions apply.
2.1
bitumen
a viscous liquid, or a solid, consisting essentially of hydrocarbons and their derivatives, which is soluble in carbon disulphide and is substantially non-volatile and softens gradually when heated. It is black or brown in colour and possesses waterproofing and adhesive properties. It is obtained by refinery processes from petroleum, and is also found as a natural deposit or as a component of naturally occurring asphalt in which it is associated with mineral matter
2.2
asphaltite
a naturally occurring substance allied to bitumen, substantially soluble in carbon disulphide and characterized by a high softening point.
2.3
asphalt
a mixture of bitumen with a substantial proportion of inert mineral matter
NOTE This term is normally qualified by the indication of the origin, e.g. natural rock asphalt. Trinidad Lake asphalt; or type, e.g. mastic asphalt, rolled asphalt.
2.4
refined lake asphalt
a naturally occurring mixture of bitumen and finely divided mineral matter, which is found in well-defined surface deposits, and from which unwanted components such as water and vegetable matter have been removed
2.5
lake asphalt-bitumen mixture
a homogeneous mixture of refined lake asphalt and bitumen, with or without the addition of flux oil, used in the manufacture of asphalts and other coated materials
2.6
asphaltic cement
bitumen or a mixture of refined lake asphalt with bitumen andlor asphaltite having adhesive qualities suitable for the manufacture of mastic asphalt
2.7
limestone
a naturally occurring consolidated stratified
calcareous rock
NOTE The term is used here in a restricted geological sense.
2.8
pigment
finely ground metallic oxide
2.9
mastic asphalt
a type of asphalt composed of suitably graded mineral matter and asphaltic cement in such proportions as to form a coherent, voidless, impermeable mass, solid or semi-solid under normal temperature conditions, but sufficiently fluid when brought to a suitable temperature to be spread by means of a hand float, or by mechanical means
3 Classification
The types of mastic asphalt are classified as follows:
R988: mastic asphalt for roofing (limestone aggregate);
F1076: mastic asphalt for flooring (limestone aggregate);
T1097: mastic asphalt for tanking and damp-proof courses (limestone aggregate); Fl 451: coloured mastic asphalt for flooring (limestone aggregate).
Types F1076 and F1451 mastic asphalt for flooring are graded according to usage as follows:
grade I: special hard flooring; grade II: light duty flooring; grade Ill: medium duty flooring; grade IV: heavy duty flooring.
NOTE 1 Types F1076 and F1451 do not cover grades of mastic asphalt for special applications such as chemical resistant, oil resistant or spark free flooring, for which purposes proprietary variants are available, nor are they suitable for external applications such as loading bays, balconies and rooftop car parks for which paving grade mastic asphalt is specified in BS 1446 and
BS 1447.
NOTE 2 A guide to the selection of the appropriate grade of flooring is given in Appendix A.
4 Asphaltic cement
The asphaltic cement for type R988 shall consist of bitumen or a mixture containing bitumen and either 25 ± 5 % or 50 ± 5 % refined lake asphalt according to the grade specified and its properties shall be as given in Table 1.
The asphaltic cement for type T1097 shall consist of bitumen or a mixture containing bitumen and 25 ± 5 % of refined lake asphalt according to the grade specified and its properties shall be as given in Table 1.
The asphaltic cement for grade I of types F1076 and F1451 shall consist of a mixture containing bitumen and 15 ± 5 % refined lake asphalt; and its properties shall be as given in Table 2.
The asphaltic cement for grades II, III and IV of types F1076 and F1451 shall consist of bitumen or a mixture containing bitumen and 25 ± 5 % refined lake asphalt according to the grade specified; and its properties shall be as given in Table 2.
NOTE The refined lake asphalt content is controlled and determined by the solubility in trichioroethylene and ash content tolerances specified for the asphaltic cement.
5 Aggregate
5.1 General
The total aggregate shall consist of fine aggregate complying with 5.2 and coarse aggregate complying with 5.3.
5.2 Fine aggregate
The fine aggregate shall consist of naturally occurring limestone rock ground to a grading within the limits given in Table 3, when determined by the wet sieving method described in Part 103 of BS 812; and shall have a calcium carbonate content of not less than 80 % by mass, when determined by the method of BS 6463-2.
5.3 Coarse aggregate
The coarse aggregate shall consist of clean igneous or calcareous rock or siliceous material obtained from natural deposits either directly or by screening, crushing or other mechanical process. If limestone is used as the coarse aggregate for flooring, the aggregate crushing value, when determined as described in BS 812-3, on chippings passing a 14 mm BS 410 test sieve and retained on a 10 mm BS 410 test sieve shall be not greater than 28.
7 Specific requirements
7.1 Type R988: mastic asphalt for roofing (limestone aggregate) and type T1097: mastic asphalt for tanking (limestone aggregate)
7.1.1 Asphaltic cement. The properties of the asphaltIc cement shall be as given in Table 1.
7.1.2 Fine aggregate. The fine aggregate shall comply with 5.2.
7.1.3 Coarse aggregate. The added coarse aggregate, if any, shall consist of material complying with 5.3 and, when tested as described in BS 812-103, its size shall be within the limits given in Table 7.
7.1.4 C’omposition. When tested as described in BS 5284 the composition of the mastic asphalt shall fall within the limits given in Table 4.
7.1.5 Hardness nunzber. The hardness number of the mastic asphalt at the time of manufacture when determined as described in BS 5284 shall be as follows:
type R988: not less than 45 and not more than 90 at 25°C;
type T1097: not less than 55 and not more than 120 at 25°C.
NOTE For hardness numbers at the time of laying see B.2.
7.2 Type F1076: mastic asphalt for flooring
(limestone aggregate) and type F1451:
coloured mastic asphalt for flooring
(limestone aggregate)
7.2.1 Asphaltic cement. The properties of the asphaltic cement shall be as given in Table 2.
7.2.2 Fine aggregate. The fine aggregate shall comply with 5.2.
7.2.3 Coarse aggregate. The coarse aggregate shall comply with 5.3; and when tested as described in BS 812-103 its grading shall comply with the appropriate requirements given in column 2 of Table 5.
9 Marking
Mastic asphalt manufactured in compliance with BS 6925 shall be legibly marked with the following:
a) the registered name or trade mark of the manufacturer;
b) the number and date of this British Standard,
i.e. BS 6925:19882);
c) the type number, i.e. R988, F1076, T1097 or F1451;
d) in the case of flooring material, the grade.
Marking shall be by a suitable labelling system or by the application of a suitable paint or by branding. Marking systems shall not impair the efficiency of the mastic asphalt when laid.
Material delivered as hot charge to site shall be accompanied by a certificate giving the information stated above.