Task 13.1 Basic mechanism study will:

	determine the mechanisms of passivation due to the inhibitors,
	assess the influence of corroded reinforcement state on corrosion inhibitor concentration requirement,
	underpin the interpretation of data generated in the applied re-search of Task 13.2 (Chloride and inhibitor concentration) and partly also that of Task 13.3 (Concrete permeability).

Task 13.2 Chloride and inhibitor concentration will examine the potential existence of an effectiveness envelope bounded by the ratio of chloride to inhibitor concentration. The objective of Task 13.2 is to quantify the relationship between the chloride level and the optimal inhibitor concentration so that one can ex-press (in terms of the probability) the likelihood of effective corrosion control through inhibitor application in a particular case.

Task 13.3 Concrete permeability will examine the potential existence of an effectiveness envelope bounded by concrete permeability values. The objectives of this task 13.3 are to:

	quantify the rate of penetration of specific inhibitors into concretes representing a range of permeabilities and to
	investigate the relationship of permeability testing to degree of penetration.

Task 13.4 Influence on mechanical properties will examine whether or not the inhibitors have any significant influence on the mechanical properties of mature concrete. The objective of this task is to determine the relative influence, if any, of amino alcohol and sodium monofluorophosphate inhibitors on the following properties of mature concrete:

	freeze/thaw resistance,
	compressive strength,
	tensile strength,
	flexural strength,
	permeability,
	shrinkage and
	reinforcement bond.

Task 13.5 Field trials will involve two distinct aspects. The first, and most important, will be the monitoring of bridges rehabilitated through application of amino alcohol inhibitors. The second aspect will involve limited field exposure trials using specimens cast in the laboratory and identical to some of those used in Task 13.2. The objectives of this task are to:

	determine significant factors of influence observable through field experience,
	validate trends observed in laboratory trials by comparison with experience in both field trials on rehabilitated structures and
	control specimens exposed to a marine environment.

Task 13.6 Specifications Description will bring together the findings of WP 13 in a manner suitable for input to WP 12. The objectives of Task 13.6 are to:

	identify specification issues in the selection of corrosion inhibitors as an acceptable rehabilitation solution on a particular structure through a review of final reports on laboratory and field trials,
	prepare guidelines on the use of inhibitors in highway structure maintenance,
	input findings of Work Package WP13 to Work Package WP12.