CHANGES IN SPECIFIC PROPERTIES OF PVC DRAINS UNDER VARIOUS STORAGE-CONDITIONS

Corrugated PVC drains should meet minimum requirements to prevent brea kage during installation and trench backfilling. Storage can alter spe cific properties of drains so that the minimum requirements are not me t anymore. To investigate the influence of storage on the properties o f corrugated PVC drains, tubes from five manufacturers were stored for 5 years in three different ways: (1) outdoors, (2) indoors uncovered, and (3) indoors covered. Specific mass and elongation were determined yearly, while impact strength and brittleness were only determined at delivery and at the end of the 5 years storage period. Specific mass and elongation did not undergo noticeable changes. Impact strength and brittleness decreased when stored outdoors, while, indoor storage did not affect these properties. Batches of drain tubing from two manufac turers, provided each year for 7 consecutive years, were also stored f or 5 years. After each year of storage the impact strength and brittle ness were determined. The average breakages of impact strength and bri ttleness of the seven batches of both products increased linearly with storage time. Impact strength and brittleness were affected significa ntly after an outdoor storage period of 1 year in humid temperate regi ons. On average, degradation is completed after about 8 years of outdo or storage. (C) 1998 Elsevier Science B.V. All rights reserved.