دانلود رایگان مقاله انگلیسی مقایسه ساختار های مواد بتن سبک با پلی اتیلن تصفیه شده و رس متراکم - الزویر 2017

Abstract

The article discusses the possibility of using high and low density polyethylene waste as aggregate in lightweight concrete with high strength cement mortar. Research is dedicated to experimental investigation and comparison of material properties of concrete made of polyethylene waste and expanded clay aggregates. Hydration kinetics studies of concrete specimens with different aggregates are performed using measurements of ultrasonic pulse velocity. For the experimental investigation high and low density polyethylene plastic waste aggregates with low water absorption and hydrophobic surface were used. It is stated that concrete with low water absorption plastic waste aggregates after 7 days of curing showed significant decrease in strength growth rate. The specimens had a density of 1950 – 2050 kg/m3 with a compressive strength of at least 40 MPa. Using pre-wetted expanded clay aggregate with similar mix composition, concrete density was 1900 kg/m3 with a compressive strength up to 70.2 MPa. Although having similar mechanical properties as the waste plastic aggregate, pre-wetted expanded clay allows better cement hydration process, resulting in lower water absorption of lightweight concrete.

6. Concluding remarks

x It was found that UPV methodology allows to observe cement hydration process peculiarities of concrete with different water absorption aggregates. After 7 days of curing concrete with plastic waste aggregates (which have a very low water absorption), a significant decrease in growth of strength properties is observed in comparison to concrete with pre-wetted expanded clay aggregate.

x Concrete composition having a density of 1950 to 2050 kg/m3 with plastic waste aggregates HDPE and LPDE has 28 days compressive strength higher than 40 MPa. Using pre-wetted expanded clay aggregate with same cement mortar resulted in the density of 1900 kg/m3 with a compressive strength up to 70.2 MPa.

x Although having similar mechanical properties as the waste plastic aggregate, higher porosity pre-wetted expanded clay aggregate creates optimal conditions for cement hydration, which results two times lower water absorption.

x Additional mechanical treatment of HDPE beads did not influence compressive strength and water absorption of concrete.

x It was found that the application of silica fume microfillers in concrete mixture at the same W/S ratio gives higher compressive strength and lower water absorption in comparison to ground quartz microfiller.