Laserfiche WebLink
EPS Geofoam 2001, 3rd International Conference, Salt Lake City,December 2001 4 <br /> sign of variation in material strength whether the retrieved specimens are tested wet or dry.This indicates that water <br /> pickup over years in the ground will not affect material strength. <br /> UNIT DENSITY <br /> The only change in design rules that have been introduced in Norway since the first fill in 1972 is that the design <br /> unit weight for EPS blocks placed in a drained position is reduced from y=1.0 kN/m3(p=100 kg/m3)toy=0.5 <br /> kN/m3(p=50 kg/m)when stability and settlement calculations are performed.For blocks placed in a submerged or <br /> semi-submerged position the value of y=1.0 Mrnm (p=100 kg/m3)is maintained.The change mentioned above is <br /> based on tests data from existing fills. <br /> EPS placed in the ground will absorb water in two ways.One is by water entering possible voids between spheres <br /> due to water pressure or capillary rise.Since water vapour may diffuse through the polystyrene when there is a <br /> temperature gradient,the <br /> 150 water vapour will condense <br /> "; in the spheres if there is a <br /> N s drop in temperature below <br /> 140 the dew point.However,in <br /> Z gg an EPS block of 500 mm <br /> 4 3E� �'iuz i �R { <br /> 130 lt� AT thickness or an EPS fill of <br /> �. ♦ Soibotmoan greater thickness the <br /> ff <br /> = 120 'a * lr ■ Flom temperature difference over <br /> r �f the block or fill will be very <br /> H =i'�� • Lan hus small:Possible water <br /> m <br /> 11U le, <br /> absorption due to water <br /> H } ♦ Lenken vapour diffusion is therefore <br /> y <br /> 100Sande expected to be small. <br /> CL <br /> s U <br /> YY <br /> E <br /> ,f �' Normal qual. <br /> V 90 Water absorption due to <br /> �l 7 <br /> f <br /> waxer pressure or capillary <br /> 80 rise depends on unit density <br /> 18 20 22 24 26 28 30 and how well the spheres are <br /> welded together.A number <br /> Density dry(kg/m3) ( )Year after construction of tests,mainly on small <br /> samples in laboratories,have <br /> Figure 4.Compressive strength on retrieved samples from EPS fills been peed in several <br /> countries in order to study <br /> water absorption effects. <br /> Both the quality of these tests and the results vary somewhat.Tests performed on samples retrieved form existing <br /> fills in Norway are in agreement with some of the laboratory tests. <br /> Tests performed on samples retrieved from three EPS fills placed in a drained position,i.e.blocks are located above <br /> the highest groundwater or flood level,all show water contents below 1 %by volume after more than 20 years in the <br /> ground(fig.5). <br /> Long term performance and durability of EPS as a lightweight filling material <br />