Plasticizers are far more than a chemical term in construction and demolition contexts. They influence the behavior of plastics in buildings as well as the workability of concrete. In practical deconstruction this becomes apparent when separating plasticized PVC components, during maintenance of hydraulic hose lines, or when demolishing concretes of different composition with concrete demolition shear and rock and concrete splitters. A sound understanding helps to realistically assess material behavior, occupational safety, and disposal routes.
Definition: What is meant by plasticizer
Plasticizers are low-molecular substances that are added to plastics, sealants, or coatings to increase flexibility, elasticity, and resistance to cold impact. Chemically, they reduce the interactions between polymer chains, lower the glass transition temperature (Tg), and make materials more formable. In construction, the term appears in two ways: on the one hand for plasticized polymers (e.g., PVC-P in floor coverings, cable jackets, films), on the other hand colloquially for plasticizing concrete admixtures (traditional plasticizers and high-range water-reducing admixtures) that improve the handling of fresh concrete. This dual meaning is important when components are opened with concrete demolition shear, concrete members are separated with concrete splitter or rock wedge splitter, or building components are selectively dismantled.
Chemical mechanisms and material effects
Plasticizers embed themselves between polymer chains, increase their mobility, and thus alter mechanical properties. Typical effects in plastics:
- lower hardness, higher elongation at break and bending flexibility
- reduced tendency to brittle fracture in cold conditions, increased impact toughness
- changed surface friction and potentially tacky behavior when warm
For concrete admixtures (traditional plasticizers and modern high-range water reducers), the mechanism is different: dispersing action on cement particles, water reduction, improved workability. This in turn affects density, strength, creep, and shrinkage—properties that influence fracture and splitting behavior during deconstruction.
Plasticizers in construction products and their significance in deconstruction
In existing buildings, plasticized plastics are found in cable jackets, floor coverings, waterstops, window profiles, waterproofing films, hoses, and coatings. During strip-out and cutting these materials often appear together with mineral building materials. This has practical consequences:
Influence on work with concrete demolition shear
Plasticized plastics deform in a tough manner and string. When gripping with concrete demolition shear, this can lead to smearing and a tendency to slip at contact surfaces. Thin-walled PVC pipes are easy to crush but rarely splinter, whereas rigid plastics break in a brittle manner. When opening wall and ceiling layers with embedded lines, varying resistance should be expected, and a clean, controlled bite with moderate feed rate is advisable.
Influence on rock and concrete splitters
Plasticizer-containing waterstops, elastic sealing profiles, or rubberized layers in composite assemblies can locally deflect crack paths or absorb energy. This can hinder initial crack initiation and require additional wedge stroke. In the concrete itself, admixtures do not act as “plasticizers” in the sense of polymer chemistry; however, they change pore structure and strength development. Higher-strength, densely packed concrete (e.g., through modern high-range water reducers) tends to require higher splitting forces and careful placement of split wedges, whereas more porous, older concretes break more easily.
Hydraulic systems, hoses, and seals: the role of plasticizers
Hydraulic power units, combination shears, concrete demolition shear, stone splitting cylinders, multi cutters, steel shear, and tank cutters operate with hoses, seals, and elastomers that often contain plasticizers. Migration and aging over time lead to embrittlement, cracking, and reduced low-temperature flexibility. This is safety-relevant:
- Media compatibility: Observe plasticizer compatibility with hydraulic fluid (including rapidly biodegradable fluids).
- Temperature management: High oil temperatures accelerate plasticizer loss and aging.
- Environmental influences: UV, ozone, and solvent vapors promote cracking.
- Maintenance: Visual inspection for cracks, tackiness, swelling; age-based replacement of hoses and seals.
A planned replacement of wear parts stabilizes performance and contributes to safe application in concrete demolition and special demolition.
Plasticizers in concrete chemistry: plasticizers and flow agents
On construction sites, plasticizing admixtures are often casually referred to as “plasticizers.” Technically, a distinction is made between traditional plasticizers (e.g., lignosulfonate-based) and high-range water-reducing admixtures (e.g., polycarboxylate-based). They enable low water-cement ratios, improve pumpability and surface finish, and can influence setting and strength development.
Relevance for deconstruction
- Higher density and strength lead to altered fracture surfaces with concrete demolition shear; crack propagation is often more linear but requires higher working forces.
- Lower porosity makes it harder to set effective split wedges with concrete splitter; precise positioning and, if necessary, pilot borehole quality become more important.
- Admixtures can modify the moisture balance and cohesion of the cement matrix—consider the impact on dust generation and fragment size.
Material identification and separation in deconstruction
For strip-out and cutting it is helpful to distinguish plasticized plastics from rigid plastics. Clues include haptics (soft, rubbery), smell (typical plastic odor), markings (material codes), and behavior in cold and under bending. Plasticized sealants and films in composite assemblies should be identified early and routed separately to facilitate source-separated disposal and recycling.
Temperature, aging, and migration behavior
Plasticizers can migrate out of the material over time. Consequences include embrittlement, a tendency to crack, and reduced energy absorption. In cold environments, formerly flexible components become fracture-prone; in warm environments, the surface can become tacky and bind dust. During thermal processing (e.g., separating, cutting), the tendency to emit increases. An adapted process strategy supports clean work and minimizes emissions.
Occupational safety and environmental aspects
When downsizing plasticizer-containing construction materials, dusts and vapors may be released. Proven measures include local dust extraction, sufficient ventilation, appropriate respiratory and skin protection, and low-dust working methods. Legal requirements for handling potentially problematic plasticizer types can vary by region; general precautionary principles, proper storage, separate collection, and documented disposal routes are advisable. In case of uncertainty, the applicable technical rules and regulatory requirements should be observed.
Use cases: impacts at a glance
- Concrete demolition and special demolition: Varying concrete compositions (with plasticizing admixtures) influence the effectiveness of concrete demolition shear and rock and concrete splitters; built-ins made of plasticized plastic require adapted gripping.
- Strip-out and cutting: Plasticizer-containing floor coverings, cable jackets, and sealants change cutting behavior; clean separation cuts and controlled feed rates reduce smearing.
- Rock excavation and tunnel construction: Plasticizers are primarily relevant in seals, hoses, and shotcrete-related admixtures; keep an eye on material aging of hydraulic components.
- Natural stone extraction: Low relevance in the rock itself; significance lies in the hydraulic periphery and sealing systems of the equipment used.
- Special operation: In industrial facilities, plasticized linings, hoses, and seals may occur; when working with tank cutters and steel shear, manage emissions and waste carefully.
Terminology distinctions and typical misconceptions
“Plasticizer” is not a single substance but a group of substances with different properties and risk profiles. In concrete, “plasticizer” does not mean softening chemicals in the sense of polymer chemistry but plasticizing admixtures. This distinction helps interpret material behavior correctly and choose the appropriate method for concrete demolition shear, hydraulic splitter (wedge), or multi cutters.
Practical guidelines for planning and execution
- Survey: Identify plasticizer-containing components (coverings, seals, cables, films) early and separate them.
- Parameterization: Adjust gripping pressure, bite sequence, and split position to material toughness and concrete properties.
- Maintenance: Renew hoses and seals of the hydraulic power pack based on condition; check media compatibility.
- Minimize emissions: Use low-dust methods, limit process temperature, employ suitable dust extraction.
- Disposal: Collect plasticizer-containing fractions separately and route them to compliant disposal.