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UniPak™ preparation, mixing and applications instructions

Fast Curing Polyester Resin Mortar

UniPak mortar is a rapid-set, high strength bedding mortar. It can be used on its own or with packing materials made from the same two part polyester resin material - a proven material used in highway construction - which sets to form a highly durable, homogenous structure. The below is a guide of how to prepare, mix and use the material.

Preparation

All substrates must be suitable to receive bedding as per current good working practices. All substrates should be clean, dry, thoroughly sound and free from oils, grease, dust, loose particles or any other contaminants which may interfere with adhesion.

Mixing (1:1, Liquid to Powder ratio)

Add the contents of the liquid additive tin to its bucket container, then slowly add the contents of the filler bag while mixing thoroughly with a slow speed drill and paddle. Mix for approximately 2 minutes. Extra liquid additive should not be added as this will reduce the hardening properties and slump resistance of UniPak mortar. IMPORTANT NOTE: The mortar will begin to set after approximately 15 minutes, after which do not try to re-mix or wetup UniPak (which at this point has gone off) with additional resin, as this will result in mortar that will not harden.

Application

UniPak mortar can be applied in a bed of 10 - 50mm in a single pass and should placed typically within 5 minutes of mixing to allow time for adjustments. The mortar must be compacted and not left as laid and the laid mortar bed must be of even thickness in order to ensure even compaction during tamping. Typically the frame should be placed on the mortar bed without voids (where UniPak Plates are not employed). Tamp the frame in place to achieve the required level. Any exposed mortar should be dressed to envelope the manhole or gully frame but not trowelled smooth. All works should be carried out in line with advice laid out in the relevant sections of the Design Manual for Roads and Bridges. An alternative method of supporting the frame on UniPak wedges and packing mortar under the frame can be employed where preferred or where the mortar working time is too short to use the above typical frame levelling method.

Restrictions

Speed of set and strength development will be affected by site and substrate temperature. Warm conditions will accelerate setting and cold conditions will slow setting. Protect freshly placed material from freezing, until set. In adverse weather conditions, UniPak mortar should not be used if the temperature is below 3˚C on a falling temperature or below 3˚C on a rising thermometer. Please also refer to the IMPORTANT NOTE in the mixing section above.

NOTE

  • Department of Transport Design Manual for Roads and Bridges Volume 7 Section 2 Part 2 HD 27/04 states: “3.11 Mortars for bedding iron work such as manhole cover frames during repairs may be trafficked when the strength is expected to be 20 N/mm2. For rapid construction, this strength should be achieved within 2 hours.”
  • Department of Transport Design Manual for Roads and Bridges Volume 7 Section 2 Part 5 HA 104/09 states: “6.1 Chamber tops and gully tops should be bedded upon bedding materials with the following properties:
  1. a. The material should be non-shrink. Use of other materials may be considered in consultation with the Overseeing Organisation;
  2. The material should have a minimum workable life of 15 minutes;
  3. The compressive strength of the material should exceed 30N/mm2 in 3 hours;
  4. The tensile strength of the material should exceed 5N/mm2 in 3 hours;”
  • National Roads Authority Manual of Contract Documents for Roadworks Volume 1 Clause 507.17 states: “17 Frames for chamber covers and gratings shall be set in cement mortar designation (i) complying with clause 2404 or a proprietory quick-setting mortar of equivalent strength. Covers and gratings located within the carriageway, hardshoulder or hardstrip shall be set in mortar with the following properties: with the following properties:
  1. The material shall be non-shrink;
  2. The material shall have a minimum workable life of 15 minutes;
  3. The compressive strength of the material shall exceed 30N/mm2 in 3 hours;
  4. The tensile strength of the material shall exceed 5N/mm2 in 3 hours.”