PDF Publication Title:
Text from PDF Page: 008
The reported residual post-cracking to peak strength ratios achieved by the HDPE FRC are satisfactory as they reach approximately 50% of the equivalent RL/Fcr strength ratio for steel fibre reinforced concrete and are about equal to the ratios reported for concrete reinforced with PP fibres [15, 31]. These results demonstrate that, even for structural applications, the performance of the recycled plain HDPE fibres is comparable to that of the commercial PP fibres which are produced with the optimised shapes to develop higher bond strength. It was observed from the failure surfaces that HDPE fibres developed large elongations before their bond strength, provided by pure friction to concrete, was exceeded. The fibres were only pulled out of concrete when the prism deflections became larger than 2.0 mm (d ≈ 4 · dcr ) and without the occurrence of the fibre tensile rupture. Further improvements to the strength properties of concrete may be achieved by introducing (recycled) HDPE fibres with the optimised geometric shape in order to develop higher bond strength to concrete. With the advances in processing of recycled HDPE, the application of mechanically and/or chemically improved fibres with the increased bond strength could result in the more resilient structural concrete capable for developing larger residual capacities. 3.3. Water permeability of FRC Concrete is a porous material whose durability is intrinsically affected by its permeability. Factors such as the increase of the fineness of cement and aggregate and the lowering of the water/cement ratio, W/C, can reduce the permeability of concrete making it more resistant to the deteriorating processes like the carbonation or the freeze-and-thaw action. To assess the influence of HDPE fibres on the permeability of concrete, three 150 mm cubes from each mix were cured for 14 days and left to dry on room temperature until the age of concrete was 45 days. Following the Euronorm 12390:8 [29] procedure, the cubes were then subjected to the constant 5 bar water pressure applied against the wire-brushed side for the duration of 72 h. Table 5: Serviceability properties of plain and fibre reinforced concrete. Test specimen Ø 0.25 mm f ibres Ø 0.40 mm f ibres readingsUnits age C1 C2 C3 C4 C5 C6 C7 Water permeability tests Hw mm 45days 43 25 36 28 33 25 26 Vi mL = Plastic shrinkage cracks wcr (max) mm 24 hours wcr mm = Crack reduction ratio: 75 50 68 63 50 50 47 0.550 0.350 0.175 0.100 0.285 0.150 0.125 0.275 0.180 0.075 0.045 0.125 0.080 0.065 CRR = [1 − wcr (Ci)/wcr (C1)] · 100% n/a 34.5% 72.7% 83.6% 54.5% 70.9% 76.4% The averaged results of the standard water permeability tests provided in Table 5 are the height of the water penetration, Hw, (measured after the cubes were split at the end of the 72 h test) and the volume of the water intake from the calibrated tanks, Vi. In all cubes with HDPE fibres, water permeability, as considered through the depth of penetration, was reduced in comparison to the plain concrete cubes in the range from 35% to ∼ 80% with the improving 7PDF Image | Mechanical properties of concrete reinforced with recycled HDPE
PDF Search Title:
Mechanical properties of concrete reinforced with recycled HDPEOriginal File Name Searched:
concrete-reinforced-plastics.pdfDIY PDF Search: Google It | Yahoo | Bing
Development of a solar powered Electric Ship The Electricship website originally started off as a project to develop a comprehensive renewable, affordable, modular electric ship... More Info
Modular Boat Hull Composite The case for a unsinkable, modular composite hybrid boat hull... More Info
MS Burgenstock Hybrid Electric Catamaran Lake Lucerne Unique shuttle servicing Lucerne to the Burgenstock Resort... More Info
Ground Power Unit GPU Powered by Lithium Ion Batteries The goal of the Ground Power Unit is to provide a readily accessible, modular, ready-to-power solution for remote power... More Info
CONTACT TEL: 608-238-6001 Email: greg@electricship.com (Standard Web Page)