The selection of fill material in highway and infrastructure projects directly affects the lifespan, carrying capacity, and long-term maintenance cost of the structure. Aggregates of calcite and dolomite origin are widely used in road paving and fill applications thanks to the hardness values they carry, their homogeneous grain distribution, and high wear resistance. At Alpay Doğaltaş, we supply fill aggregate by the ton to construction firms and infrastructure contractors from various dolomite and calcite deposits across Turkey, principally from Marmara Island Saraylar.
The sub-asphalt fill layer is a critical layer that transfers the load of the road structure to the ground. The aggregate used in this layer is expected to compact well, have controlled water permeability, and not deform under traffic loads. Generally, graded mixed aggregates in the 0-20 mm or 0-40 mm range are preferred. In such mixtures, the fine and coarse grains coming together in the right ratio minimize the void ratio after compaction and provide high carrying capacity. The calcite-based mixed aggregates we supply are prepared at our partner processing facilities in compliance with standard grading curves.
In concrete road layers, the purity and strength values of the aggregate become more prominent. Concrete roads, while longer-lasting than asphalt, require stricter quality criteria during production and application. The aggregate used in these applications must directly contribute to concrete strength. Calcite Aggregate in the 7-12 mm and 12-22 mm grain classes is the preferred range in concrete road mixtures. A high CaCO3 ratio combined with low absorption values increases the concrete's resistance to freeze-thaw cycles.
The use of aggregate as fill material is not limited to road projects. Infrastructure trench fills, retaining wall back fills, drainage line construction, and ground improvement works also feature aggregate as a fundamental material. In trench fills, especially the fine-grained aggregate laid around pipes protects the pipe from mechanical impacts while at the same time allowing water drainage. The 3-7 mm range is frequently preferred in these applications. In retaining wall back fills, coarse-grained aggregate allows the discharge of water without creating soil pressure.
The relationship between grain size and compaction is the technical foundation of fill performance. In a well-graded mixture, smaller grains fill the voids between larger grains, so the unit volume weight after compaction increases and the fill gains a stronger structure. In poorly graded mixtures, compaction remains insufficient, and over time settlement, cracks, and deformation may appear on the road surface. For this reason, we share basic grading data with each shipment of fill aggregate, directing the right product according to the project's technical specifications.
