Journal of Civil Engineering and Materials Application
Volume:6 Issue: 4, Autumn 2022

With the growth of the urban population and the development of cities, water distribution systems have become very important. Considering the complexity of these systems and the large scale of decision-making in analysis, design, operation and maintenance, the need for computer modelling of networks has become more important. The most important issue in modelling is consistency between calculated and measured data. The amount of unaccounted water in a distribution system can be determined by conducting water balance studies in the system or in an enclosed measurement area. It can be seen that determining the optimal pattern of unaccounted water to complete the data of total water consumption in the network in a seta model, in a situation where the results of unaccounted water studies are not available, is still needed as one of the main elements in model calibration. . In order to solve this problem, the current research was carried out in order to review and improve the continuous model of water distribution network by introducing, checking and implementing an optimal integrated experimental approach of the unaccounted water model. The use of the option of the inverse model of the customers' consumption is not considered as a water model; for calibrating the hydraulic model of the distribution network, it provided a more acceptable simulation in the maximum range from 30% to 4% and in the average maximum difference from 23% to 3%.

Grading is one of the most important characteristics of cement, which has a great impact on its performance in concrete. The most common methods of monitoring are determination of residues on sieves, Blaine and LD. In this study, introduce the main parameters of cement grading, optimal limits and its effects. Also 204 samples of Portland cement were prepared to determine their physical and mechanical properties and performance of Laboratory concrete mixtures. One of the most important results is the clear effect of increasing the share of 3 - 30 µ particles and cement uniformity coefficient on the compressive strength of concrete and mortar and providing relationships. The results of LD- PSD experiments were well correlated with the experiments remaining on the sieve by alpine method. With increasing uniformity or the amount of particles of 3 - 30 microns, the setting time of cement paste increases (becomes longer); which is not always desirable

Self-Compacting Concrete is a revolutionary concrete that has taken Europe, the America and Asia by storm following its development by Prof. Okamura’s research team in the late 20th century. Since then, it has been revolutionized into various improved forms either by tinkering with the constituents and mix design towards perfecting it or by use of locally available secondary cementitious materials and fillers that are ecofriendly and economical, thereby reducing the carbon footprint as well as enhancing its properties. This research looks into the possibility of using Microbial Induced Calcite Precipitation on the engineering properties of calcined clay and Limestone powder blended ternary Self-Compacting Concrete, with emphasis on the evaluation of the fresh state properties as well as strength and durability. Calcined clay was used as Supplementary Cementitious Material at 15% replacement of cement and Limestone powder as filler, with Sporosarcina Pasteurii as MICP bacteria at different bacterial cell densities of 1.5x108cfu/ml, 1.2x109cfu/ml, and 2.4x109cfu/ml, (McFarland turbidity scale of 0.5, 4.0 and 8.0 respectively) and calcium lactate (nutrient) concentration of 0.5%, 1.0% and 2.0% by weight of cement incorporated into the ternary blend. The strength is evaluated using compressive strength (at 7, 28 and 56 days curing) and split tensile strength (at 7 and 28 days) while the durability characteristics are evaluated using water absorption (7, 28 and 56 days) and sorptivity (7, 28 and 56 days) and the microstructure investigated using Standard electronic microscopy. The result indicates an overall improvement in the properties of the Self-compacting concrete.

In this research, with the aim of reducing the costs of maintenance and use of construction machinery in the road construction sector, the methods of increasing the time intervals for changing the engine oil of these machines have been discussed. Accordingly, as a case study, this goal was achieved in an excavator of the Komatsu PC220-7 model using SAA6D102E-2-C engine oil by means of an engine oil condition monitoring system that was used at intervals of 55, 110 and 165 hours of operation. Machines have been investigated in construction and road construction projects. The main parameters of this research include viscosity at 40 degrees Celsius, alkaline number, erosive elements (iron, chromium, aluminum, copper, lead), oil additives (zinc, phosphorus, calcium), oil contaminants (calcium, sodium and Boron) and Particle Quantifier for each of which a standard index has been considered and the change of these parameters in three periods of 55, 110 and 165 hours of vehicle engine operation has been investigated. Also, as an economic discussion, the cost parameters in Iran for these conditions have been investigated. The results of this research showed the good performance of the oil during 165 hours of engine operation.

Recent earthquakes indicate that the welding connections of steel moment-resisting frames (SMRFs) are so brittle. Then, huge damages are generated by cracking the weld between the beam flange and column face. After the 1994 Northridge and the 1995 Kobe earthquakes, reduced beam section (RBS) connections were proposed to reduce the damages by forming a plastic hinge outside the panel zone. Thus, with the great effect of seismic performance and ductility of the panel zone, RBS moves the formation of the plastic hinge at a suitable distance from the column face. In this regard, in order to evaluate the behavior of SMRF with RBS connections under fire conditions, four types of steel frame connections, including RBS with radial, rectangular, triangular, and trapezoidal cuts, were modeled in ABAQUS software. Due to the fact that fire is an unpredictable phenomenon, both in terms of size and fire load, it has special complexities. The fire load was simulated either by a steady state method to reach a fully-developed fire or by a transient state method following the standard temperature–time curve. The results of this study showed that by increasing the temperature of the heated area, the transferring of the plastic hinge is conducted better. Meanwhile, based on the obtained outputs of displacement-time coefficients, the Frame-RBS-01 sample had the most ultimate strength compared to other samples up to 748.34 ° C temperature, and the least ultimate strength is related to the Frame-RBS-Rectangle-02 sample up to 526/90 ° C temperature.