DURABILITY AND ENVIRONMENTAL IMPACT OF CEMENT MORTAR LININGS A
REVIEW OF DURABILITY
To review critically the current state of knowledge on the durability of cement mortar linings used for the renovation and/or corrosion protection of ferrous water mains.
Cement mortar lining activity has significantly increased to meet 'levels of service' regulatory requirements in a cost effective manner. There is a requirement to relate life expectancy to supply water quality for the purpose of asset management planning. Knowledge of durability will enable more accurate estimates of the effective lifetime of cement mortar linings.
Studies to date have shown that lime may be lost from factory applied cement mortar lining surfaces at rates of up to
0.1 mm/year. Sand rich gel layers are formed, which appear to provide protection from corrosion. In certain situations the durability of the gel layer may be compromised and it is reported that high aluminium cement (HAC) mortars form gel layers with greatly enhanced durability. There is apparently no UK and little international durability data available for in situ cement mortar linings.
V RESUME OF CONTENTS
An introduction to the durability of cement mortar linings is provided. UK experiences with the durability of cement mortar linings are presented, including previously unpublished data. International experiences are also presented, with reference to data which support the theory that lime depleted linings can be effective corrosion inhibitors in certain circumstances. Recommendations for further work are made.
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