| December 1, 2012

tuffsand is designed for use in the construction of unbound pavements. It permits the slight movement of paving elements; a necessity for the long term health of all unbound pavement construction. tuffsand swells on saturation with water to allow realignment of aggregate particles within the joints to self-heal following the application of an overbearing load or fatigue caused by over-trafficking. In its normal state, or once healed, tuffsand provides significantly stiffer restraint of the paving elements than pavior sand. Normal New Zealand annual rainfall is sufficient to facilitate the self-healing cycle of tuffsand.

tuffsand is water permeable but not free draining. The permeability of a pavement jointed with tuffsand is dependent on several factors including, but not limited to, saturation, width and depth of joint, dimensions of paving elements, depth and permeability of bedding, base and foundation layers. Rate of water absorption of tuffsand is dependent on several factors including, but not limited to, density of compaction, joint dimensions and existing level of saturation.

tuffsand is highly elastic in compression and in normal conditions, used as a stabilised substitute for unbound jointing sand, may not be sufficiently overloaded to fail in compression.

tuffsand is highly resistant to abrasion resulting from mechanical cleaning, however resistance can vary according to changes in ambient temperature and moisture levels. Joints eroded by extreme weathering, excessive mechanical cleaning or accidental damage may be topped up by repeat applications of tuffsand in accordance with the method statement.

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Category: Enviropave

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