Discoloration of paving block surfaces –Case examples and their evaluation

Figure: MPVA Neuwied

Damage pattern 1: claimed pavement

Figure: MPVA Neuwied

Damage pattern 1: color difference between a retained sample and the blocks of the pavement

Figure: MPVA Neuwied

Damage pattern 1: ambient sources of contamination

Figure: MPVA Neuwied

Damage pattern 1: contamination on the block surfaces (on the left, contaminated block surface/on the right, gained contaminant)

Figure: MPVA Neuwied

Damage pattern 2: discolored pavement of a company parking lot

Figure: MPVA Neuwied

Damage pattern 2: small partial area, where the paving blocks still roughly feature their original color

Figure: MPVA Neuwied

Damage pattern 2: investigation of a discolored paving block (left) and the contaminant separated from the block surface (right) with the help of a digital microscope

Figure: MPVA Neuwied

Damage pattern 2: laboratory test for the reproduction of discoloration of paving blocks by applying the joint material

Figure: MPVA Neuwied

Damage pattern 3: pavement with the contaminated anthracite-colored concrete slabs

Figure: MPVA Neuwied

Damage pattern 3: contaminated walkway area (left) and concrete slabs not yet installed and stored on pallets (right)

Figure: MPVA Neuwied

Damage pattern 4: terrace area with anthracite-colored concrete slabs showing discoloration

Figure: MPVA Neuwied

Discolorations due to the use of black joint material used for concrete paving blocks colored white

Figure: MPVA Neuwied

Source of contamination: fertilizer

Figure: MPVA Neuwied

Source of contamination: grass clippings

Figure: MPVA Neuwied

Biological growth due to shadowing and tannins of trees

Figure: MPVA Neuwied

In the last few years, the number of complaints about discolored concrete block pavements has increased considerably. On the basis of selected examples and current rules and regulations, this technical paper is dealing with several damages, which are not (always) in the responsibility of the manufacturer of concrete blocks, and it evaluates the damage patterns.

In the last few years, the number of complaints about discolored concrete block pavements has increased considerably [6], [7], [9], [10]. This raises the question why the number of complaints owing to discolorations has increased so much in recent years. The investigation of these damages reveals that the increase of such complaints is subject to different root causes:

1. Increased entitlement mentality on the part of customers;

2. Complaints as a means to cut expenses when installing pavements both in private areas (terraces, driveways) and in public paved areas, where neat streetscapes but...