2013 Archive

Physical and mechanical property of EPS

1.1The density

The density of EPS is decided by the expansion of the forming stage of polystyrene particles multiples, generally between 10 ~ 45 / m3, as used in the engineering of EPS apparent density generally in 15 ~ 30 / m3. Currently used as the light in the road eng

ineering packing density of the EPS is 20 / m3, 1% ~ 2% for the common way of packing. Density is an important indicator of EPS, almost all the various mechanical properties and its density is proportional to the relationship.

1.2 Deformation characteristics

According to the test, the EPS in three-way under uniaxial stress st

 

ate and stress state of the compression process of basic similar, when axial strain epsilon a = 5%, the stress strain curve appear obvious turning point, EPS began to show the elastoplastic. When the confining pressure is small, the stress-strain relationship and the influence of the yield strength is limited. When the confining pressure more than 60 kpa, yield strength decreased obviously, obviously with the change rule of different soil. When the axial strain epsilon a 5% or less, regardless of the confining pressure is, the volume strain epsilon v epsilon is close to the axial strain a, the lateral deformation is small, the EPS is poison’s ratio is small. Bulk density of gamma = 0.2 ~ 0.4 kN/m3 EPS of elastic modulus Es between 2.5 ~ 11.5 MPa.

1.3 Independence

EPS independence is strong, the high slope stability is good. The rules and regulations of Sweden bridge design, active, static lateral pressure coefficient was 0 and

 

 0.4, respectively, need not calculate the passive side pressure. Because of EPS after vertical compression of lateral pressure is small, the EPS used in the bridge section of subgrade filling, can greatly reduce the abutment back earth pressure, the abutment stability is good.

EPS blocks and the friction factor f of sand, to dry sand f 0.58 (close) to 0.46 (loose), on the wet sand f 0.52 (close) to 0.25 (loose); F between EPS block to block in the range of 0.6 ~ 0.7.

1.4 water and temperature characteristics

EPS of the closed cavity insulating structure determines its good stays, it is used for thermal insulation material the biggest characteristic is its low thermal conductivity, all kinds of EPS board its thermal conductivity is 0.024 W/m.K ~ 0.041 W/m.K.

EPS to hot plasticity resin, should be used under 70 , so as to avoid heat deformation and intensity is reduced. Using this feature can be used at the same tim

 

e heating wire processing. 1.5 The durability

EPS in the water and soil chemical properties of stability, cannot be microbes; The cavity structure of EPS also make water infiltration extremely slow; For a long time by ultraviolet irradiation, EPS surface will be changed from white to yellow, brittle and materials to some extent presented; In most of the solvent EPS nature is stable, but soluble in gasoline, diesel, kerosene, toluene, acetone and other organic solvents. This suggests that the EPS packing need good protective layer.