Aggregation Of Amount Research Articles

Sustainable development of concrete through treated and untreated plastic waste aggregates

This study focused on sustainable and novel development of concrete through treated and untreated plastic waste aggregates. In this study, the surface of Elec-waste coarse aggregates was treated with sulfuric acid, marble dust coating, silica fume coating, and alkaline bleach. Elec-waste aggregates were used in concrete by replacing natural coarse aggregates in amounts of 10%, 20%, and 30%. The 10%, 20%, and 30% Elec-waste replacement ratios resulted in the compressive strength reduction of 8.97%, 27.99%, and 42.01%, respectively. The same percentage of Elec-waste aggregates reduced the splitting tensile strength by 21.77%, 35.89%, and 47.89%, respectively. However, the slump was observed to increase by 41.4%, 52.1%, and 68.8%, respectively. All the considered treatments enhanced the performance of Elec-waste aggregate concrete (E-WAC). Overall, the best improvement in the performance of E-WAC was imparted by silica fume coating, irrespective of the quantity of Elec-waste aggregates. The present study proposed an expression to estimate the reduction of the compressive strength of E-WAC. It was demonstrated that the equation by JCI-08 predicted splitting tensile strength of E-WAC close to experimental results.

Mechanical, Durability, and Gamma Ray Shielding Characteristics of Heavyweight Concrete Containing Serpentine Aggregates and Lead Waste Slag

Heavyweight concrete is used to prevent harmful radiation for the construction of hospital, military, and nuclear power plants and also to increase the durability for the construction of marine concrete structures. In this research, using a combination of serpentine aggregates and lead slag, the mechanical, durability, impact resistance, and shielding properties of heavyweight concrete were examined. The variables included fine and coarse serpentine aggregates, which were replaced with normal fine and coarse aggregates in amounts of 0, 25, 50, and 100 percent, respectively. The lead slag in all samples was considered constant. Slump, compressive strength, flexural strength, water penetration depth, impact resistance (drop hammer), and gamma ray attenuation coefficient tests were conducted. The chemical composition of serpentine aggregates and lead slag were evaluated by X-ray powder diffraction. The results showed that the density and linear attenuation coefficient (LAC) increased with the increase of fine and coarse serpentine aggregates in heavyweight concrete containing lead slag. The highest density and LAC were obtained in a sample in which 100% fine serpentine aggregates and 100% coarse serpentine aggregates were used. Using 25% of serpentine fine aggregates and 25% of serpentine coarse aggregates in heavyweight concrete samples containing lead slag has achieved the highest compressive strength and flexural strength. But with the increase of fine and coarse serpentine aggregates to more than 25%, the upward trend of increasing compressive strength decreased. Silica constitutes a large part of the chemical structure of serpentine aggregates (about 42%). Increasing the amount of serpentine aggregates in concrete mixes leads to excessive release of calcium hydroxide in concrete. This issue can lead to the formation of a weak zone in concrete and decrease the compressive and impact resistance.

Sustainable Design and Engineering: A Relationship Analysis between Digital Destructive and Non-Destructive Testing Process for Lightweight Concrete

The development of sustainable lightweight materials is a promising field solution in this era. The production of sustainable materials by replacing coarse aggregates with some lightweight alternative provides a good quality construction material. In this study, rocky coarse aggregates were replaced by an ultra-lightweight material (i.e., expanded polystyrene beads) to produce an equivalent rock-solid mass of concrete. Using an M15 grade of concrete composition, expanded polystyrene (EPS) beads were added in place of aggregates in amounts ranging from 5% to 40% at a water–cement (w/c) ratio of 0.60. The specimen size as per American Society for Testing and Materials (ASTM) specification was 150 mm in diameter and 300 mm in length. Furthermore, statistical analysis for the relationship study for destructive testing (DT) (i.e., compressive test machine) and non-destructive testing (NDT) (i.e., rebound hammer and ultrasonic pulse velocity (UPV)) has been performed at developed specimens under 7- and 28-day curing conditions. In the end, the results showed that NDT predicts higher compressive strength than that of DT with the addition of EPS beads up to 20% aggregate replacement, after that it is vice versa for up to 40% aggregate replacement. This study will not only help in the production of sustainable lightweight materials, but especially concrete block production can also be performed at a large scale as a sustainable engineering solution.

Properties of concretes produced with waste concrete aggregate

An environmentally friendly approach to the disposal of waste materials, a difficult issue to cope with in today's world, would only be possible through a useful recycling process. For this reason, we suggest that clearing the debris from destroyed buildings in such a way as to obtain waste concrete aggregates (WCA) to be reused in concrete production could well be a partial solution to environmental pollution. For this study, the physical and mechanical properties along with their freeze–thaw durability of concrete produced with WCAs were investigated and test results presented. While experimenting with fresh and hardened concrete, mixtures containing recycled concrete aggregates in amounts of 30%, 50%, 70%, and 100% were prepared. Afterward, these mixtures underwent freeze–thaw cycles. As a result, we found out that C16-quality concrete could be produced using less then 30% C14-quality WCA. Moreover, it was observed that the unit weight, workability, and durability of the concretes produced through WCA decreased in inverse proportion to their endurance for freeze–thaw cycle.