Toproc A13 Pitsea Viaduct

Product: Toproc SS

Project: A13 Pitsea Viaduct – Carriageway Remedials

Main Contractor: Tarmac National Contracting

Consulting Eng: Mouchel Parkman

Client: Essex County Council

Project

Tarmac National Contracting were instructed by their client Essex County Council to carry out both a geotechnical survey and to also conceive a design for the joint repairs on the A13 Pitsea
viaduct. Scot Wilson Pavement Engineering were the consultant engineers used by Tarmac National Contracting for the design which included the removal part of the slabs on either side of each failed joint. The concrete was replaced at full depth, in typically 2.5m3 pours, and needed to achieve in addition to the normal design criteria a compressive strength of 20N/mm2 in 4-5 hours to allow the remedials to be carried out overnight and the carriageway to be reopened at 6.00am the following morning. The repair works were carried out over five consecutive nights in November 2004.

 

Toproc Performance

The performance achieved from the Toproc SS delivered to this project was in line with that indicated on the Toproc SS typical strength development graph shown opposite.  The repaired areas were opened to traffic at 6.00am each morning and when inspected again after 16 hours of use there was no degradation of the brushed finish that had been applied only 4-5 hours before trafficking. The repairs were carried out within a very constrained time period to minimise disruption on thisvery busy viaduct.

 

Design Constrainsts

Design Constraints The very rapid early strength gain required for this contract could only be satisfied using our highest performing microsilica concrete formulation – Toproc SS
(Super Strength). Concrete strength gain at an early age is temperature dependent;
therefore we design Toproc SS to optimise both the increase, and the rate of increase, in the in-situ temperature.  The actual in-situ temperature achieved, and therefore the rate of strength gain achieved is dependent on four main factors:

Concrete Mix Design
Ambient temperature
Depth of section (and therefore mass) of element being cast
Rate of heat loss from cast concrete

Tarmac Limited Proposal
Toproc SS proprietary microsilica concrete. Indicative 4-5 hour compressive strength in excess of 20N/mm2. 

After final finishing it is important that a 90% efficient spray-on type curing agent is applied to the concrete surface to reduce the incidence of plastic cracking.

The use of thermal insulating blankets placed on to the cast area immediately after pouring to
maintain the heat of hydration that is developed.

See more on Toproc

 

See all Concrete Products and Services

Back to Concrete Home