Journal of Civil Engineering and Materials Application
Volume:8 Issue: 1, Winter 2024

This study explores the impact of low carbon Rice Husk Ash (RHA) on the rheological and mechanical properties of mortar. RHA, sourced from Nigeria, underwent chemical analysis to ascertain its pozzolanic activity index. Rheological tests conducted on the mortar included standard consistency, initial and final setting times, as well as fresh density of mortar. While mechanical properties such as compressive, tensile, and flexural strength were assessed. Ordinary Portland Cement (OPC) was partially substituted with RHA at varying intervals with 0% RHA serving as the control. Compressive strength was measured after 7, 14, and 28 days of water curing, while tensile and flexural strength were evaluated at the 28th day. The water-to-binder ratio was fixed at 4.85, and binder-to-fine aggregate ratios of 1:2.36 and 1:2.76 were employed. RHA was classified as Class N, indicating high pozzolanic capacity. Results revealed increased consistency, initial and final setting times and a decreased density with RHA addition. The peak compressive strength was observed at 10% RHA, reaching 8.759 and 10.252 MPa for mix ratios 1:2.75 and 1:2.36, respectively. Moreover, at 10% RHA, flexural and tensile strength for mix ratio 1:2.36 exceeded those of plain mortar by 22.5% and 9.6%, respectively. In conclusion, the study highlights the significant role of RHA as a pozzolanic material in enhancing cementitious reactions in mortar systems, though the influence of RHA particle size was not considered.

One of the major concerns of concrete manufacturers is the use of cements resulting from the depot of clinker and remain in cement plants. Depoted clinker is exposed to rain and surface hydration reduces the quality. Therefore, a laboratory operation was designed. During this study, a ton of Portland clinker type 1-425 was prepared and stored in a roofless area. Cementing was performed with a laboratory mill from this clinker at 1 day, 1, 2, 3 and 6 months. For uniformity, fineness was constant in all five cement samples and Blaine index of 3100±100 cm2/gr was considered. Physical tests of cement including blaine, setting time, residue on sieves and strength of mortar were performed on all samples. Concrete mixes with constant slump were also made. At each stage, chemical analysis, microscopic studies and clinker gindability were performed. The results of concrete strength showed that clinker stay for 6 months, a decrease in compressive strength of mortar and 28-day concrete causes about 300%. This comparison for clinker showed that during 6 months the alite phase is reduced by about 14% in chemical analysis and about 40% in microscopic studies. (Due to the small depot volume of this project compared to the actual volumes, these results are quite strict and the use of results must be careful.)

In any transportation planning, including rural transportation, the characteristics of existing supply and demand must be identified. According to this knowledge, the main needs and problems of the villagers in the field of transportation can be identified. In urban transportation planning, travel models are usually built in four stages. In the first stage, travel production and absorption models, in the second stage, travel distribution models, in the third stage, vehicle mode choice models, and in the final stage, route selection and traffic assignment models. In this study, and according to the studies conducted on the difference in behavioral pattern as well as the difference in the way of planning in the village and city, modeling related to the stage of production and absorption of travel is done using backward elimination regression. This study was conducted by case study of a number of villages in Qazvin city and can be generalized to other villages that have similar characteristics. Finally, according to the developed models, it was found that in work trips, the variable of employment rate, in educational trips, the number of students, in shopping trips and ethnics and medicine and in the demand of total travel variable population have the greatest impact on the model. With the current situation demand, it is possible to develop a forecast demand model for different horizons by applying the population growth rate and employment. By estimating the demand for travel, in order to create and build road and rural facilities, road pavement and road maintenance can be planned.

This paper presents the results of an investigation into the influence of aggregate and binding material type on the mechanical properties of hardened concrete. To perform this investigation, four different types of coarse aggregate (Brick Aggregate, Recycled Brick Aggregate, Black Stone and Shingles) and eight types of binding material have been used. Aggregates were collected and prepared according to the grading requirements of ASTM C33-03. Several tests, such as specific gravity, absorption capacity, unit weight and abrasion resistance were performed for coarse aggregate. Cylindrical concrete specimens were made with different W/C ratios and cement contents. A total of 42 different cases were considered for testing. The specimens were tested for UPV, compressive strength, stress-strain curve and Young's modulus at the age of 28 days. The major objective of this study was to investigate the mechanical characteristics of concrete for different types of aggregate and binding materials. From the study it was found that, UPV of concrete specimens made with brick aggregate and recycled brick aggregate found lower than that of made with shingles and black stone. Black stone gave the best combination of high Young’s modulus as well as high compressive strength to the concrete in comparison to others. Shingles gave the best combination of high UPV as well as high compressive strength to the concrete in comparison to others. Young’s modulus and compressive strength of concrete increased with a decrease in the w/c ratio for any type of aggregate and increased with an increase in cement content.

This article focuses on modeling and numerical analysis of the effects of an explosion on the body of an earthen dam in an injection gallery. Earthen dams play an important role in providing water for agriculture, electricity generation, and flood control. However, these dams are exposed to various risks, including explosions that can be caused by military operations and industrial accidents. Even geological activities such as earthquakes occur. An explosion in an earthen dam can have severe and irreparable consequences, including structural damage to the dam, downstream flooding, and even complete dam failure. Therefore, identifying and reducing the risks associated with such incidents is of great importance. _ The researchers in this research aim to investigate the effects of the explosion on the Tezreeq gallery. An earth dam using Abaqus modeling software and numerical analysis with Python. The main goal is to gain a better understanding of the behavior of earthen dams during explosions and provide effective solutions to reduce the associated risks. The problem is defined by presenting the general characteristics of the dam, including its type, the height of the river bed at the dam site, the maximum height of the dam, and other relevant parameters.The details of the construction of the injection gallery, including its length and cross-sectional dimensions, have also been described. In addition, the explosion process and its consequences, such as the rapid release of energy, gas production, and the release of pressure waves, have been explained.