Journal of Materials and Engineering Structures
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Effect of Waste Plastic and Fiber Modification on Asphalt Mixture Properties
Full text linkStone Matrix Asphalt (SMA) and Asphalt Concrete (AC) are widely used in road construction due to their excellent mechanical properties and long-term durability. This study investigates the effect of sisal fiber and waste plastic as modifiers to enhance the performance of SMA and AC mixtures. The Marshall mix design method was employed to determine the optimum bitumen content (OBC) and optimum fiber content (OFC), evaluating parameters such as Marshall stability, flow value, air voids, voids in mineral aggregate (VMA), and voids filled with bitumen (VFB). VG 30 grade bitumen was used as a bitumen, and fly ash was utilized as a filler. Sisal fiber was incorporated to reduce bitumen drain down and improve crack resistance, with the optimal fiber content identified as 0.4% by total mix weight. Simultaneously, waste plastic was added to improve workability and mechanical performance, with 2.5% content enhancing handling characteristics and 3% improving drain-down resistance and tensile strength. Results from drain down and moisture susceptibility tests indicated that the combined use of sisal fiber and waste plastic significantly improved the durability and overall performance of the asphalt mixes
An Examination of Reclaimed Asphalt Pavement's Role as Aggregate in the Composition of Structural Concrete: An Extensive Overview
Full text linkThe process of renovating flexible pavement produces an extensive amount of reclaimed asphalt pavement (RAP). These aggregates are frequently discarded, whether through legal or illegal means, in nearby locations, thereby creating various challenges for regulatory bodies. The incorporation of these aggregates into portland cement concrete (PCC) mixtures represents an innovative strategy that could yield significant socio-economic and environmental advantages. Nonetheless, the inclusion of RAP aggregates may also adversely impact both the soundness and performance characteristics of the concrete. This paper delivers a detailed and critical evaluation of the practicality of employing RAP aggregates in concrete production, while also pinpointing several shortcomings that must be rectified to enhance sustainability in construction methodologies. This paper is structured in the following manner: it initiates with a detailed characterization of RAP aggregates, followed by an analysis of the characteristics of fresh concrete containing RAP, and culminates in an exploration of RAP containing concrete mechanical and durability characteristics. According to the literature review, it is evident that aggregates derived from RAP are generally of a lower quality than their natural counterparts. This may not pose a significant issue regarding the characteristics of the fresh concrete. The asphalt film and the presence of agglomerated particles within the RAP were identified as key factors contributing to the diminished strength and durability characteristics. The integration of RAP as aggregates has been associated with notable advantages, including improved toughness. Furthermore, existing research suggests that the performance of concrete containing RAP can be enhanced through the processing of RAP in conjunction with using supplementary cementitious materials (SCMs) or fibres
Novel Glass Fiber Composites Reinforced with Date Seed-Derived Carbon for High-Performance Submarine Hulls
Full text linkThis study examines glass fiber-reinforced polyester composites enhanced with carbon derived from date seeds as potential materials for submarine hull construction. Mechanical, physical, and microstructural properties were evaluated through tensile, flexural, compression, impact, density, and water absorption tests. Composites containing 0.5–2.0 wt% carbon were fabricated and assessed under varied loading and environmental conditions. Results show that the 0.5% carbon composite achieved the highest impact toughness (0.137 J) and flexural modulus (95,639.879 MPa), indicating superior resistance to dynamic and bending stresses. The 2.0% carbon composite recorded the greatest tensile strength (4,844.308 MPa) but lower flexibility, whereas the 1.0% carbon composite displayed the lowest density (0.97 g/cm³), enhancing buoyancy for marine use. All samples exhibited 0% water absorption, confirming excellent moisture resistance. SEM–EDS analysis revealed uniform reinforcement dispersion and strong interfacial bonding, particularly in the 0.5% hybrid composite. Overall, the findings highlight date seed–derived carbon as a sustainable reinforcement capable of improving the strength-to-weight ratio of glass fiber composites. It offers a lightweight, corrosion-resistant alternative to conventional metals for submarine structures, warranting further optimization and field testing for marine deployment
Experimental study on transverse behavior of concrete box girder bridges with strutted wing slabs
Full text linkIn 2023, the first box girder bridge with strutted wing slabs in Vietnam was put into use in the Ring Road II Viaduct Project in Hanoi. As this is an innovative type of traditional box girder bridges and completely new in Vietnam, prior to the commencement of the project, an experimental program was conducted to check the construction technology and obtain valuable experimental data for design and further numerical analyses. A full-scale girder segment with a width of 18.7 m, a length of 6 m and height of 2.5 m, incorporating steel pipe struts, was fabricated. Three distinct load cases were conducted to investigate the transverse behavior of strutted wing slabs, steel pipe struts and connections under the most unfavorable load conditions at Service Limit State. This paper presents a detailed experimental program with test results. It is shown that with applied loads varying from 1.2 to 1.5 times the service load, both the deck slab and steel pipe struts still exhibited linear manner, maintaining sufficient load-bearing capacity. However, with increased applied load in Load Case 2, cracks occurred along the construction joint region, indicating that attention to construction joint quality in real projects is needed to pay great attention to ensure the integrity of structures. Based on the conducted experiment, some recommendations are proposed for future implementation of such bridge typologies
Investigating the effects of aggregate gradations on the compressive strength and the cost of concrete using two proportioning methods
Full text linkOptimizing aggregate gradation in concrete mixtures has an impact on concrete properties such as strength, durability and sustainability. Many aggregate proportioning methods have been proposed to solve aggregate gradation issues. The Tarantula Curve is a recently developed aggregate proportioning technique that can evaluate aggregate gradations and can give insights of the quality of the gradations. Since the Tarantula Curve have been having great success in the United States in producing concrete mixtures with outstanding performances and lower cost, this work aims to validate the gradation boundaries of the Tarantula Curve using local aggregates in Saudi Arabia by measuring the compressive strength and the workability. This work also provides a comparison between the Tarantula Curve method to the ACI 211. The results showed a reduction in the compressive strength and poor workability when the 20% limit is exceeded for the coarse aggregate retained on a single sieve. Similarly, as the limits of sieve sizes 150 µm and 75 µm were exceeded, the compressive strength decreased, and poor workability performance was observed in the mixtures. Harsher mixtures were produced as the 2.36 mm sieve limit was exceeded. It was found that the Tarantula Curve produced mixtures with a 35% higher in compressive strength and 6% lower in cost as opposed to the ACI 211 mixtures. These data and tests provide recommendations and framework for further comparative testing in the durability testing in the futur
Effect of the fineness of mineral additions on the behavior of low impact environment self-compacting mortars
Full text linkThe aim of this experimental work is to analyze the effect of mineral additions fineness on the hydration of self-compacting mortars, as well as their behavior in the fresh and hardened states. To do this, cement was partially replaced with a fixed rate of 20% for natural pozzolan and 30% for slag. The additions were ground to three different fineness. The results showed that the use of slag is favourable to the formulation of self-compacting mortars, the workability has been considerably improved, the increase in its fineness, meanwhile, reduces the dosage of superplasticizer up to 46%. For the pozzolan, on the other hand, not only was the workability reduced, but the increase in fineness implies an additional demand for superplasticizer up to 16%. Mortars based on additions release less heat, nevertheless, this reduction is accompanied by a drop in compressive strength at a young age. However, the increase in fineness lets to accelerate the initial hydration, inducing additional strength, and to generate heat comparable to that of the reference mortar. Nonetheless, in the case of excessive grinding, the heat release must be taken into account in order to avoid the thermal cracking
Research on the use fly ash and bottom ash from coal-fired power plants for making concrete lagging at underground mines
Full text linkVietnam currently has 26 coal-fired power plants in operation, emitting a total amount of coal ash about 16 million tons/year of Fly Ash (FA) and Coal Bottom Ash (CBA). FA and CBA increase the costs of landfill space, and negatively affect the environment. Now, concrete lagging with steel arches is the biggest proportion of the type of current structural support in underground mining (about 70÷80%) in Quang Ninh coal area, Vietnam. The main objective of this research is to propose an optimized proportion of the FA and CBA of thermal power plants used in concrete mixture on making concrete lagging in SVP steel arches. This paper also presents the results of an experimental study using FA and CBA for making concrete lagging with the optimized proportion as cement and sand by the Advantest 9 (Control- Italy) system at the Laboratory of Underground and Mining Construction of Hanoi University of Mining and Geology (HUMG). The study result can be concluded that cement and sand replacement by FA and CBA are useful in lower grades of concrete such as M200 in making laggings of SVP steel arches of the underground mines in Quang Ninh coal area and in contributing to the environment protection
Research on heat resistance of A60 fire-resistant doors used on ships using CFD numerical simulation
Full text linkTypically, the design of fire doors on ships is mainly to meet thermal requirements, while thermal deformation can also significantly affect the safety performance of the door. When the fire temperature is high, the door tends to warp and deviate from the supporting frame due to uneven temperature distribution, which may lead to the spread of fire and smoke on ships. To evaluate their performance, fire doors must undergo a standardized fire test. Realistic simulation of this fire test can be of great benefit during the design phase in order to reduce the number of prototypes to be manufactured and tested. This article researches the testing process of A60 fire-resistant doors installed on ships. The A60 fire-resistant door consists of two steel plates, each measuring 1600x600x45 mm, with a 42 mm thick layer of mineral wool insulation placed between them. Test sample were heated in a gas-fired furnace for 60 minutes. The findings are given in the form of a temperature-time chart showing that the test sample meets the requirements for fire-resistant doors used for ships. This study holds significant importance for the development of the shipbuilding industry in Vietnam in the near future
Strength, microstructure, and environmental assessment of mortar containing stone waste and admixtures
Full text linkThe swiftness in the speed of construction work is the present scenario's need to meet the infrastructure demand due to rise in industrialization and urbanization. Various admixtures are being used to produce mortar/concrete with acceleration in stiffening of cement composites and requisite strength at early age. However, due to industrialization, the generation and dumping of stone wastes in different forms from stone industries has become menace to the ecosystem. To overcome their ill effects, a possible solution can be reuse of these wastes into the construction sector as it can absorb huge waste. This study used stone slurry powder as cement substitution; calcium nitrate and triethanolamine as additives in different proportions individually and in combination to investigate their practicality in cement mortar. The environmental assessment of additives in mortar mixes was also carried out along with the microstructural analysis. Results demonstrated that water cured specimens had higher compressive strength and air cured specimens had higher electrical resistivity values. The stone powder was predominant among all additives in the performance enhancement in terms of strength, chemical resistance and environmental assessment of mortar mixes as compared to other additives
Effect of Coarse Recycled Concrete Aggregate on the Microstructural and Durability Properties of Self Compacting Concrete
Full text linkThis paper presents the influence of different amounts of Coarse recycled concrete aggregate (CRCA) obtained from a Construction and Demolition Waste (CDW) Plant in Delhi, on the durability properties of a 40 MPa Self Compacting Concrete (SCC). Aggregate Packing (bulk) Density (APD) method was adopted to obtain an aggregate mixture exhibiting maximum bulk density/least void content (45%) with which the SCC mixes was prepared. In addition, SCC was also made using aggregate mixtures in which the Natural coarse aggregate (NCA) was replaced with CRCA at 0% and 100 % (of the total coarse aggregate content). It has also been observed with the Mercury intrusion porosimetry (MIP) and Scanning electron microscopy (SEM) analysis that the incorporation of fly ash in SCC mixtures containing different contents of CRCA, resulted in the production of SCC-CRCA mixtures, with higher/comparable performance to that of control SCC mixture. The test results indicated that the SCC mixtures SCC mixtures exhibited very low chloride ion permeability at 28 days, lower carbonation depth. SCC made with CRCA up to 45% replacement can be used for structural concrete which is higher than that recommended in Indian specification (20 %) for normal concrete