Scope 1.1 This specification covers cold & hot applied crack filler and hot applied joint & crack sealants for use in filling/cealing cracks in asphalt concrete and cement concrete pavements.
Crack sealing/filling has two purposes:
- To prevent the intrusion of water through the crack into the underlying layers of the pavement structure which would further weaken the pavement.
- To prevent incompressible materials from entering the crack as these may cause further deterioration as the pavement expands and contracts with temperature changes.
2.1 Recommended filling/sealing materials are given in Table 1.
|Bitumen Emulsion (Cationic Type)||IS 8887||Filling|
|Modified Bitumen||Table 1||Sealing|
2.2 Crack filling is usually done on non-working cracks with Bitumen emulsion, or liquid bitumen(hot) and is considered to be a temporary procedure. These crack fillers are usually to be a temporary procedure. These crack fillers are usually only effective as long as the pavement remains quite stationery, both longitudinally and vertically. Once expansion and contraction or excessive vertical movement occurs the effectiveness of filler can be lost and cracks must be refilled. The severity level of the climate in a particular area will dictate how refilling needs to be done.
2.3 Crack sealing is accomplished where cracks are subject to expansion and contraction using specially prepared hot poured sealant. Crack sealing would be considered a permanent crack treatment. Three to eight years is the general expected life; depending upon the material used, the condition of the pavement, and the techniques used when applying crack sealant.
2.4 The sealant shall be composed of a mixture of materials that will form a resilient and adhesive compound capable of effectively sealing joints and cracks in concrete and asphaltic pavement against the infiltration of moisture and foreign material throughout repeated cycles of expansion and contraction with temperature changes, and that will not, at ambient temperatures flow from the joint or be picked up by vehicle tires. The material shall be capable of being brought to a uniform pouring consistency suitable for completely filling the joints without inclusion of large airholes or discontinuities and without damage to the material. It shall remain relatively unchanged in application characteristics for at least 6 hour at the recommended application temperature in the filled.
3.1 Type I-A joint and crack sealant capable fo maintain an effective seal in moderate climates. It is a hot applied crack sealant for as halt and concrete pavements. It can be used to seal cracks with a maximum width of 15mm. 3.2 Type II-A Joint and crack sealant capable of maintaining an effective seal in most climates. It is a hot applied sealant for joints and grooves in concrete pavements and fro cracks wider than 15mm in asphalt and concrete pavements.
4.1 Maximum heating temperature:- The maximum heating temperature is the highest temperature to which a sealant can be heated and still conforms to all the requirements specified herein. For purpose of testing, the application temperature shall be the same as the maximum heating temperature. The maximum heating temperature shall be set forth by the manufacturer and shall be provided to the testing agency before any laboratory tests are begin.
The two types of sealant shall conform to requirements prescribed in Table 2.
Table 2 Requirements for sealants
5.1 The seating compound shall be delivered in the manufacturer's original containers. Each container shall be legibly marked with the name of the manufacturer the trade name of the sealant; the manufacturer's batch, or lot number and specification number and types the maximum application temperature and maximum heating temperature. The maximum hating temperature must be 11°C high than the maximum application temperature.
|SI. No.||Characteristics||Sealant||Test-Ref No.|
|2||Type I||Type II||IS No|
|1||Penetration at 25°C, 0.1mm 100g, 5 Sec||90-130||40-70||1203|
|2||Softening Point, (R&B),°C,Min||80||90||1205|
|3||Ductility at 15°C, cm||90||60||1208|
|4||Elastic recovery at 25°C % Min||90||90||Annex. A|
|5||Viscocity at 185°C, mpas||200||600||IS1206(Part2)|
|6||Fraass Breaking Point°C Max||-20||-18||9381|
(Clause and Tables)
The elastic recovery of sealant is evaluated by comparing recovery of thread after conditioning for 1 h at specified temperature and the specimen is elongated up to 10 cm deformation in a ductility machine. This is intended to assess degree of bitumen modification by Elastomeric additives. The cross-section of thread shall be as shown in fig.
A-3.1 Ductility Machine and Moulds-As per IS 1208 and Fig.1.
A-3.2 Thermometer- Any standard thermometer (ASTM 63°C) of equivalent range and accuracy shall be used.
A-3.3 Scissors- Any type of conventional scissors capable of cutting modified bitumen at the test temperature.
A-3.4 Scale- Any transparent scale of measuring up to 25cm with ± 1mm accuracy.
A-4.1 Prepare the test specimens in a set of three moulds as per dimensions given in Fig. 1 and condition as prescribed in test method of IS 1208. Elongate the test specimen at the specified rate to a deformation of 10 cm at a rate of 5± 0.25 cm/min. Immediately cut the test specimen into two halves at the mid-point using the scissors. Keep the test specimen in the water bath in an undisturbed condition for 1 h before testing.
A-4.2 After the 1 h time period, move the elongated half of the test specimen back into position near the fixed half of the test specimen so the two pieces of modified bitumen just touch. Record the length of the recombined specimen as x.
Calculate the percent/elastic recovery by the following procedure:
Elatic recovery (%)= x 100
x=length of recombined specimen