Green concrete production incorporating waste carpet fiber and palm oil fuel ash

With the increasing amount of waste generation from various processes, there has been a growing interest in the utilization of waste in producing building materials to achieve potential benefits. This paper highlights the results of an experimental investigation on the performance of concrete incorporating waste carpet fiber (WCF) and palm oil fuel ash (POFA) as partial replacements of ordinary Portland cement (OPC). Six volume fractions varying from 0 to 1.25% of 20-mm-long carpet fiber were used with OPC concrete mixes. Another six mixes were made that replaced OPC with 20% POFA. The specimens were cured in water and tested for fresh and hardened state properties. The combination of WCF and POFA decreased the slump values and increased the VeBe time of fresh concrete. The addition of WCF to either OPC or POFA concrete mixes did not improve the compressive strength or modulus of elasticity. At 91 days, the compressive strength was in the range of 38.1e49.1 MPa. The positive interaction between WCF and POFA, however, leads to high tensile and flexural strengths, thereby increasing the concrete ductility with higher energy absorption and improved crack distribution. The maximum increases in tensile and flexural strengths compared to those of plain concrete were achieved by the addition of 0.5% carpet fiber at the age of 91 days. The ultrasonic pulse velocity (UPV) was examined and was classified as good quality concrete. The study showed that the use of waste carpet fiber and palm oil fuel ash in the production of sustainable green concrete is feasible both technically and environmentally

Protection of buried rigid pipes using geogrid-reinforced soil systems subjected to cyclic loading

YesThe performance of buried rigid pipes underneath geogrid-reinforced soil while applying incrementally increased cyclic loading was assessed using a fully instrumented laboratory rig. The influence of varying two parameters of practical importance was investigated; the pipe burial depth and the number of geogrid-layers. Measurements were taken for pipe deformation, footing settlement, strain in pipe and reinforcing layers, and pressure/soil stress on the pipe crown during various stages of cyclic loading. The research outcomes demonstrated a rapid increase in the rate of deformation of the pipe and the footing, and the rate of generated strain in the pipe and the geogrid-layers during the first 300 cycles. While applying further cycles, those rates were significantly decreased. Increasing the pipe burial depth and number of geogrid-layers resulted in reductions in the footing and the pipe deformations, the pressure on pipe crown, and the pipe strains. Redistribution of stresses, due to the inclusion of reinforcing layers, formed a confined zone surrounding the pipe providing it with additional lateral support. The pipe invert experienced a rebound, which was found to be dependent on pressure around the pipe and the degree of densification of the bedding layer. Data for strains measured in the geogrid-layers showed that despite the applied loading value and the pipe burial depth, the tensile strain in the lower geogrid-layer was usually higher than that measured in the upper layer