A RADICAL BUT NECESSARY INTERVENTION
The first site for the complete renovation of the paving in Piazza Venezia was opened at the end of March last year, just next to Piazza Madonna di Loreto on the Fori Imperiali side of the Piazza. This intervention was considered absolutely necessary by the Rome City Council in order to eliminate age-old problem of depressions and holes in the road surface and pavement that have been bothering drivers and pedestrians who use the Piazza for a long time.
The work, commissioned by SIMU (the Council’s Infrastructure Development and Urban Maintenance Department), is just the first phase of a more articulated, extraordinary maintenance plan for the whole of Piazza Venezia. In order to identify the most appropriate way of tackling the problem, a core-sampling campaign was carried out which highlighted the need for more in-depth structural work.
The intervention involved the demolition and complete rebuild of around 3,000 m2 of existing road foundations, repair work on the cobblestones and the realignment of the paved edging around the various sectors of the Piazza.
So, for the time being at least, the intervention discussed in 2014, to remove the lava stone blocks that cover around 170,000 m2 of the Piazza and replace them with asphalt, has been abandoned.
THE WINNING INSTALLATION SYSTEM THAT RESISTS THE RIGOURS OF TIME
With Mapei Technical Services on site to follow the work, the MAPESTONE SYSTEM was the “turnkey” solution provided for the new paving in the Piazza, a system that ensure work remains more durable over the years and is resistant to de-icing salts and freeze/thaw cycles.
A system designed also to overcome the problem of mechanical stresses, as in this case. In fact, the constant passage of cars and heavy goods vehicles generate compressive stress (the weight of vehicles) and tensile stress (manoeuvres carried out by vehicles) that cause subsidence in weak and irregular substrates on which the blocks of stone that make up the paving have been installed.
The new substrate is formed by a slab made from class Rck 350 N/mm2 cast concrete reinforced with 20 cm electro-welded mesh set at a medium pitch.
The paving, on the other hand, is in basoli paving stones measuring 180 x 80 x 17 cm, with each one weighing around 600 kg, and smaller blocks in various sizes ranging from 12 to 15 cm.
The stone slabs were laid and grouted with MAPESTONE TFB 60 and MAPESTONE PFS 2 ready-mixed cementitious mortar with high compressive strength and exposure class XF4 according to EN 206-1:2006, particularly suitable for its resis-
tance to de-icing salts and freeze/thaw cycles.
The combined use of these products creates a monolithic structure which hardly deteriorates over the years.
A layer around 5 cm thick of MAPESTONE TFB 60 was spread directly over the concrete slab and, before repositioning the paving, the substrate was carefully hydro-blasted to remove all the cement laitance, oil, grease and crumbling and detached parts.
Immediately after spreading and levelling off the MAPESTONE TFB 60, a layer of bonding slurry made from water, cement and PLANICRETE was applied using the “wet-on-wet” technique before tamping the slabs into place. The gaps between the slabs (around 1 cm, as per the original layout of the paving) were then filled with MAPESTONE PFS 2, which was mixed only with water in a vertical mixer directly on site.
Higher durability of the finished paving, less maintenance and/or repair work, no wasted material and quicker installation times: these are the main economic advantages of the MAPESTONE SYSTEM, highly appreciated, as in this case, by operators and clients alike.
While waiting for the rest of the Piazza to be renovated (new tenders to complete work on the surrounding road network were issued at the beginning of the year), the MAPESTONE SYSTEM really has “laid the foundations” for the overhaul of this symbolic piazza in the capital city.