Gebze-İzmir Motorway Project Bears Emülzer's Signature

The Gebze-Izmir Highway not only reduces transportation time but also demonstrates awareness through numerous engineering structures. The Osmangazi Bridge, with a main span of 1550 metres and total length of 2682 metres, is the world's fourth longest suspension bridge by span. Numerous Emülzer products were used on the Osmangazi Bridge and its connecting roads. Manufacturing operations exposed directly to natural conditions require truly significant attention and dedication. In on-site production of major structures and precast beam assembly, many structural chemistry products are utilized. While elevation heights reach up to 100 metres, reinforced concrete manufacturing may not proceed as smoothly as in theory. Anionic bitumen emulsion Emülzer Emilkote was used as tar-coating on foundations. During elevation construction, due to prevailing weather conditions and groundwater effects, structures may remain submerged for months. Despite this, no water solubility whatsoever was observed in the product. The same product was also used in culverts. Occasionally, concrete repairs may be necessary due to causes such as concrete pouring defects or excessive rebar density. For repairs of resulting structural damage, three-component, epoxy-based, high-strength, flowing grout mortar Empoxy 420 was used. For concrete repairs in areas where formwork could be installed, single-component, cement-based, non-shrinking, flowing Emülzer EM-Grout N was used. Due to the grout's flowing properties, this application (provided the repair area permits formwork installation) yielded more successful results. Mortar seeping between reinforcement ribs also reaches voids that can form behind the steel, allowing creation of an impermeable, void-free structure. Repair and maintenance work arose in underpasses and culvert interiors. For repairs of concrete surfaces with segregation and closure of tie-rod holes, cement-based, fiber-reinforced, high-strength, structural thick-set repair mortar Emülzer EM-80 T was used. For finer concrete repairs, to close bird's-eye voids, cement-based, polymer-modified, fine repair mortar Emülzer EM-70 T was used.

On overpasses, where concrete would be left exposed, surface appearance is also important. Even in concrete cast on the same day from the same concrete plant, colour variations can occur. To address these colour differences, acrylic-based Emülzer Beyazcoat, matching concrete colour, was used.

Natural soil conditions are not uniform everywhere. Placing a rigid structural material such as wide-span reinforced concrete as a single piece over this variable soil composition would cause structural damage. For this reason, expansion joints must be provided. Under section 6.3.4 Effects of Expansion, Shrinkage and Creep in TS 500, the following details are given: Considering temperature variations and shrinkage effects, expansion joints should be arranged in the superstructure of hyperstatic structures with excessive lengths. In structures exposed to external effects, joint spacing should not exceed 40 m. In frame-type structures protected from temperature variations and with rigid barriers at their ends, joint spacing may be increased to 60 m. These limits may be exceeded provided calculations accounting for time-dependent behaviour are performed or special measures reducing shrinkage are taken. In asymmetric systems and, despite being symmetric, systems with rigid vertical elements preventing lateral displacement on both sides, care should be taken to keep block lengths between joints smaller. A single-component Emülzer PU Primer was first applied to these expansion joints of approximately 30 mm width, followed by application of single-component, polyurethane-based Emulseal PU Sealant. In major structures, for bonding rubber elastomer bearings to concrete under precast bridge beams, two-component, epoxy-based repair and assembly mortar Emülzer Empoxy 310 was used. As seen in the 1999 Marmara Earthquake, the most damage during earthquakes occurs from poor adhesion of elastomeric bridge bearings to concrete. Bearings not chemically bonded to concrete shifted and fell. As a result, beams either dropped or broke. The Highway Authority also applied grouting techniques for repair. Regarding waterproofing chemicals, K.T.Ş. 312.02.05 (Highway Technical Specifications) states: "It may be used with Administration permission provided it meets required performance values in terms of material application, safety, etc. and complies with TS EN 1504-2 standard requirements and has CE certification." Thus, the path is opened for liquid membranes. In this project, bitumen-based membrane was used for water insulation of bridge, viaduct and overpass decks. However, Emülzer products were preferred as primer. Toll booths on highways are exposed to hydrocarbons CxHy. These hydrocarbons, such as petrol, seep into concrete and cause damage. Joint gaps in concrete sections have types resistant to jet fuel as well. Two-component, bitumen-polyurethane-based Emülzer HDM PU 2K was used in these joint locations.

In summary;

Many structural chemistry products can be used in a highway project. Quality control laboratories on construction sites can conduct concrete, soil and asphalt tests. Where gaps remain, universities or Highway Authority laboratories come into play. Unfortunately, quality control departments on sites are not well-liked and are considered units that slow work or obstruct progress. However, a good quality department brings both financial benefit and reputation to the contractor. We should prioritize "Experimental Engineering," including structural chemicals. Projects should proceed with products from firms that have tested and passed, moving to procurement based on price/quality performance.