Laterlite Asphalt Concrete Mixtures with Expanded Clay LWA
ASPHALT CONCRETE MIXTURES WITH EXPANDED CLAY LWA
ASPHALT CONCRETE MIXTURES WITH EXPANDED CLAY LWA
Asphalt mixtures are composed of bituminous hydrocarbon binders and a “granular fraction”, i.e. a combination of aggregates of different sizes and characteristics, mixed to obtain an asphalt concrete.
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CHARACTERSTICKS
Laterlite expanded clay lwa, used as a component of the bituminous mixture to replace part of the natural aggregates, significantly improves its technical characteristics.
BRAND
Laterlite
PRODUCT TYPE
Mixture
BASE
Asphalt concretes based on laterlite expanded clay lightweight aggregates are hot mixed in conventional asphalt batch mix plants: the absolute quantity of hydrocarbon binder per cubic metre of bituminous concrete, remains the same as that used for traditional bituminous mixes, as well as the manufacturing process, the aggregates being non-adsorbent.
USE
Construction
ENVIRONMENT
Outdoor
RECYCLED ASPHALT
Better grip and anti-skid characteristics of recycled asphalt, more homogeneous and stable mix, possibility to increase the percentage of binder according to the needs.
GRIP
High grip over time better lateral friction coefficients for anti-skid road surfaces and lower wear with respect to the best basalts, either for open-graded permeable friction courses or fine-graded surface courses.
OPTIMISATION
Depending on the percentage of expanded clay aggregate used and the choice of particle size, as well as the optimisation of the binder, these mixtures have characteristics of noise reduction, drainage, high adherence, or lightness.
CLAY
A variable percentage of expanded clay included in the mix, from 11% – 13% by weight, significantly increases the sound absorption (by 3 dB)
DETAIL
SOUND-ABSORBING ASPHALT PAVEMENT : LIGHTWEIGHT ASPHALT
Low density asphalt concrete can be produced by replacing a higher percentage of natural aggregates with lightweight expanded clay aggregates. Lightened bituminous mixes can be used both as a binder course and as a wearing course on top of existing structures, especially in the case of maintenance and repair of bridges and viaducts, or in car parks on slabs or on decks, existing or new, to avoid overloading.
PERMEABLE AND ANTI-SKID ASPHALT : LIGHTWEIGHT ASPHALT
Accelerated polishing coefficient (a.P.C.) of the aggregates used. This characteristic does not remain constant over time: in fact, due to contact with the tyres and the aggregates a gradual process of polishing of the asphalt mix surface occurs.
This phenomenon, which take place after a few months of road use, tends to progressively reduce the skid resistance of the road (reduction of the coefficient of lateral friction).The use of expanded clay, thanks to its a.P.C., gives the bituminous mix higher coefficient of lateral friction values than can be obtained with the best basalts (either in open-graded permeable friction courses or fine-graded surface courses) and constant over time.
HOT ASPHALT RECYCLING : LIGHTWEIGHT ASPHALT
Expanded clay is used in hot in-place asphalt recycling, adding a maximum of 10% of the weight of the aggregates, to provide the wearing courses with high performance in terms of surface grip (coefficient of lateral friction > 57).
Another important function of laterlite expanded clay is to stabilise the bituminous mix by preventing the accumulation of fine particles and by regulating the distribution of the bituminous binder.The addition of expanded clay allows, if necessary, the use of higher percentages of binders, without the risk of backflow, and improves the chemical and physical characteristics of the conglomerate thanks to its high “buffering” characteristics. Hot asphalt recycling with expanded clay can be carried either for open-graded permeable friction courses or fine-graded surface courses.
