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Go to Editorial ManagerOpen graded asphalt mixture is becoming more widespread where it is applied for various purposes, e.g. drainage of rainwater effectivity, traffic safety (high skid resistance), and controlling pollution noise. However, it has many other disadvantages, of which low stability, high stripping, and moisture sensitivity. The research aims to study the effect of styrene butadiene styrene SBS addition on the volumetric and mechanical properties of open graded mixture. In this research one type of aggregate with gradation (12.5 mm NMAS), asphalt of penetration grade (40/50), and cement as filler were used. Optimum asphalt content was selected based on the criteria of air voids content, asphalt drain down, permeability, and abrasion resistance (for aged and un-aged) samples. Other properties of open-graded mixtures, such as indirect tensile strength (ITS), moisture susceptibility, Marshall stability and flow were evaluated. The results show that addition of polymer (SBS) leads to an enhancement in the properties of the modified mixtures. There is an improvement in Marshall parameters. Also, a slight decreasing is noticed for permeability and air voids. For Cantabro abrasion loss (aging and un-aging condition), the abrasion resistance is increased, the drain down of asphalt is decreased from original mixture by addition of SBS. Finally, the moisture sensitivity is improved indicating that modified mixes becomes more resistant to water damage.
Bio-cement built on microbial induced carbonate precipitation MICP, be able to consolidate the loose grains and can applied for soil reinforcement. In this study, the performing of an ureolytic Sporosarcina Pasteurii for sand stabilization was estimated. The S. Pasteurii Could effectively consolidates sand particles through urea hydrolysis and the successive production of calcite. The bio improved sands had relative great compressive strength after 60 days exposure to bacterial cells injections cycles. The compressive strength of bio stabilized sands was reliant on the utilized cell concentrations and density of urea and CaCl2. High bacteria cell masses decreased the compressive strength. The optimal density of cell, was OD600 0.5, when cost and performance were taken into account. The study shows that bio cementation of sand built on microbial induced carbonate precipitation (MICP) has ability for the reduction of sand permeability through pore clogging with precipitated carbonate.
A dam failure results in losses in terms of economy and infrastructure, in addition to the loss of many lives and assets. Inadequate seepage control procedures are typically the cause of seepage failure in earth-fill dams. For an earthen dam to be waterproof and to minimize seepage, non-homogeneous dams with a clay core are one kind of embankment dam used. As water moves through the dam's core, friction causes it to lose a lot of energy. Both vertical and inclined cores can be used in the design and construction of zoned embankment dams. As a result, choosing the proper materials and dimensions for the earth dam's core is critical. The main objective of this study is to investigate different seepage control strategies for an earth dam (HORAN DAM) using the Finite Element Method (FEM). We modeled and analyzed nine cases of various seepage control techniques that have been modeled and analyzed using SEEP/W, a FEM-based software. The modeling results show using chimney filters reduces pore water pressure more effectively than using toe rock and horizontal filters. Regarding seepage, trapezoidal cores perform better than inclined cores, and the milder slope is preferred over steeper core slopes. The results show when the core permeability decreases, the seepage quantity also decreases. Toe rock decreases seepage more than horizontal filters and chimney filters. Additionally, it has been shown that using a toe rock filter together with a trapezoidal core with a mild slope performs better than using a different filter and a different internal clay core shape.
Concrete is considered the most important and widely used building material in the world of construction and building due to its durability, high efficiency in shaping, and relatively reasonable cost. The main component of concrete is cement, and one of the most important problems related to cement is the environmental problems associated with cement manufacturing, as the cement manufacturing process releases a large amount of carbon dioxide. Despite the essential role of concrete in construction, we cannot ignore its environmental impact. Some claim that exploring alternative materials or innovative building techniques would reduce the carbon footprint and enhance sustainability in the industry. Partial cement replacement with pozzolanic materials like zeolite is a key technique to reduce carbon dioxide emissions. Zeolite, which reduces permeability, is a typical concrete ingredient that strengthens and lasts. Recently, natural zeolite has become a prominent concrete pozzolanic component. For environmental preservation and sustainable development, various experiments were done on concrete with pozzolanic components partially substituting cement and compared to ordinary concrete. A partial replacement of cement with zeolite improves the properties of concrete up to a certain age and mixing ratio. More than 44 relevant articles from 2004–2024 were selected from 762 papers evaluated for this paper. This paper reviews natural zeolite research in real applications. Additionally, it provided a cutting-edge review of natural zeolite literature through a critical analysis of various previous investigations. It also helped to understand how zeolite influences concrete mixture workability, strength, and durability. Since zeolite is a major concrete ingredient, it should be promoted as a sustainable resource.