EFFECTS OF SOIL pH ON MECHANICAL PROPERTIES OF GLASS REINFORCED PLASTIC PIPES

Abstract

Influence of soil pH on the mechanical characteristics of glass reinforced plastic (GRP) pipes type was often investigated in different situations encountered in the field. GRP degradation is directly proportional to the exposure to soil with non-neutral reaction. The theoretical and experimental results lead during time to design standards, which allow the application of GRP pipes in water and soil, so as minimum interferences with the materials used in the manufacture of pipes would appear. Samples of GRP pipe of a certain size are buried in the different areas of the field where the pH is alkaline, acidic, or neutral. After 24 months, samples were dug up / recovered and then subjected to laboratory determinations in GRP pipe factory Subor in Turkey in July 2016, and in Dresden Amitech Factory Laboratory in September 2016. Some other analyses were performed in the OSPA, Iaşi, Romania Laboratory. For the analysis of such large volume of experimental data, we used the Pearson correlation coefficient. The dependencies among variables were quantified by proposing the index pipe damage. The degradation of the pipeline is directly proportional with the difference between the actual value of soil pH and the neutral pH value. The mechanism of degradation is different in basic and acidic soils. The results obtained in this study can be used in practice to avoid the negative effects of the types of land on GRP pipes behavior.

System for Increasing the Seismic Safety of Pipelines in the Water Supply and Distribution Networks

“…Based on experience in the seismic actions of the water supply and distribution networks, the following statistical elements were broken down: In a large proportion, pipe failure occurs through transverse rupture, and ruptures in the stiffening areas (anchorage massifs, manholes, and building foundations) [6]. A conclusion can be drawn that most of the damage suffered by pipelines was where the route coincided with the direction of seismic wave propagation.…”

Experimental Study on the Behaviour of Seismic Actions on a Flexible Glass-Reinforced Plastic Structure Used in Water Transport Pipes

“…Most often, the observed ruptures are based on other forces, which produce longitudinal stresses of the pipe, such as tension-compression caused by axial forces or longitudinal bending, generated by bending moments and shear forces in the cross-sections of the pipe. These stresses in the cross-sections indicate a bent bar or beam behaviour and result in the appearance of normal axial stresses in the pipe walls [ 28 , 29 ]. One of the major causes that produce a stressed bar or beam behaviour upon axial bending of the pipes is the movement of the ground due to external forces, such as seismic action or other dynamic stresses.…”

The Influence of the Environment for Glass-Reinforced Plastic Composite Material Used for Ground Water Transport Pipes

“…They are used in various applications and fields, such as water and sewerage pipes, tanks, the automotive industry, aeronautics, petrochemicals, energy, sports products, construction, etc. The chemical composition of the material is at least 98% silicon dioxide (quartz sand), calcium alumina silicates (fibreglass) and thermally hardened resins [4].…”