Effect the Local Fly Ash on Cement Mortar Properties

من المفيد التخلص من النواتج العرضية لمعامل الطابوق لتفادي التلوث البيئي، لكن التحدي الكبير هو استخدام هذة النواتج العرضية وأستغلالها في تحسين مواصفات المواد الانشائية للبناء لمواكبة التطور الحاصل في تصنيع هذه المواد. هذه الدراسة البحثية تتناول احد النواتج العرضية للطابوق المحلي وهو الرماد المتتطاير لمعامل انتاج طابوق الاصلاح الواقعه في مدينة الناصرية في جنوب العراق.تم استخدام النواتج هذه المعامل المحلية لتقييم تأثيرها على مواصفات ملاط الاسمنت وذلك بعد استبدال نسبة وزنية من الاسمنت بهذة المادة.ان نسب الاستبدال اخذت كالتالي 5%،10%،15%،و 20% من وزن الاسمنت. وتم مقارنة النتأئج مع ملاط الاسمنت القياسي. ان عملة التحقق البحثية شملت ,مقاومة الانضغاط،زمن التجمد،حرارة الاماهة والكثافة.حيث أن النتأئج اوضحت ان زيادة نسبة استبدال الرماد المتطاير في ملاط الاسمنت يزيد زمن التجمد الابتدائي بصور مميزة وكذلك يزيد زمن التجمد النهائي.ومن جهة اخرى يقلل حرارة الاماهة المبكره والقصوى.أيضا الكثافة تظهر تناقص متناسب بزيادة نسبة الاستبدال للرماد المتطاير.في حين مقاومة الانضغاط في العمر المبكر ،3أيام، أظهرت انخفاض عن قيمة الملاط القياسي لجميع نسب الاستبدال لرماد المتطاير، ولكن المقاومة في العمر المتأخر ،28 يوم، أظهرت زيادة ملحوظة لبعض النسب من الملاط القياسي وهما النسبتان 5% و 10% والنسبة التي أظهرت اعلى مقاومة أنضغاط هي 10%.It is good to disposal the byproducts of bricks factories because of pollution of the environment. But the big challenge is to use these byproducts while imposing the properties of construction material and keeping pace with materials technology progress. So, in this study a byproduct (fly ash) of Al Aslaah bricks factories in the south Iraq is used to evaluate the effects for physical properties of the Portland cement mortar. Mortar cubes of 7cm were cast with fly ash partial replacement of cement weight (5%, 10%,15% and 20%) and compared against standard cement mortars cubes. The investigations involved the compressive strength, setting time, heat of hydration and density. While the results illustrate that the increasing of fly ash replacement percentage has significant increase in initial and final setting time and reduces the early and peak temperature of hydration. Also the density got proportionally less values with increasing the fay ash replacement. However, at early ages, 3days the compressive strength values were declined for all the fly ash percentages, but the situation changed for percentage 5% and 10% fly ash replacement at later age and the compressive strength were passed the standard cement mortar values at age 28days

Prediction of the Compressive Strength of Fly Ash Geopolymer Concrete by an Optimised Neural Network Model

This article presents a regression tool for predicting the compressive strength of fly ash (FA) geopolymer concrete based on a process of optimising the Matlab code of a feedforward layered neural network (FLNN). From the literature, 189 samples of different FA geopolymer concrete mix-designs were collected and analysed according to ten input variables (all relevant mix-design parameters) and the output variable (cylindrical compressive strength). The developed optimal FLNN model proved to be a powerful tool for predicting the compressive strength of FA geopolymer concrete with a small range of mean squared error (MSE = 10.4 and 15.0), a high correlation coefficient with the actual values (R = 96.0 and 97.5) and a relatively small root mean squared error (RMSE = 3.22 and 3.87 MPa) for the training and testing data, respectively. Based on the optimised model, a powerful design chart for determining the mix-design parameters of FA geopolymer concretes was generated. It is applicable for both one- and two-part geopolymer concretes, as it takes a wide range of mix-design parameters into account. The design chart (with its relatively small error) will ensure cost- and time-efficient geopolymer production in future applications

Proposed simplified method of geopolymer concrete mix design

The research aims to determine the best combination of the controlling factors that govern geopolymer concrete’s mechanical and physical properties by utilizing industrial waste. Therefore, a review on the controlling factors was conducted. Firstly, it is to identify the controlling factors, namely chemical composition, alkali activation solution, water content, and curing condition. Secondly, understanding the relationship between these controlling factors and the properties of geopolymer concrete. These factors are analysed to the mix proportion components. Finally, a new proportion method is proposed based on combining ACI 211 standard and recommended molar ratios of oxides involved in geopolymer synthesis. The effect of aggregate has been taken into account by applying the absolute volume method in mix design. Based on the results of the study, it is expected to determine the optimal mix proportions based on multi-responses

Prediction of the Compressive Strength of Fly Ash Geopolymer Concrete by an Optimised Neural Network Model

This article presents a regression tool for predicting the compressive strength of fly ash (FA) geopolymer concrete based on a process of optimising the Matlab code of a feedforward layered neural network (FLNN). From the literature, 189 samples of different FA geopolymer concrete mix-designs were collected and analysed according to ten input variables (all relevant mix-design parameters) and the output variable (cylindrical compressive strength). The developed optimal FLNN model proved to be a powerful tool for predicting the compressive strength of FA geopolymer concrete with a small range of mean squared error (MSE = 10.4 and 15.0), a high correlation coefficient with the actual values (R = 96.0 and 97.5) and a relatively small root mean squared error (RMSE = 3.22 and 3.87 MPa) for the training and testing data, respectively. Based on the optimised model, a powerful design chart for determining the mix-design parameters of FA geopolymer concretes was generated. It is applicable for both one- and two-part geopolymer concretes, as it takes a wide range of mix-design parameters into account. The design chart (with its relatively small error) will ensure cost- and time-efficient geopolymer production in future applications

The Attitude of Load-Deflection for Concrete Beams with Polymer Reinforcement

In this research, the load-deflection behavior is explored for concrete beams reinforced with FRP bars (polymer reinforcement). An experimental test is done for a total of five beams subjected to 4-point loading. The tested specimens are of dimensions; 2100 mm (length), 200 mm (width) and 300 mm (depth), while the used compressive strength for concrete is f’c = 60 MPa. Four beams were longitudinally reinforced by various CFRP rebar numbers, and the last beam was reinforced only by steel bars as control beam. Relationships for load-deflection were drawn and the influence of several factors was debated on this relationship. It was exhibited that the failure of FRP reinforced samples was generally ruled by the concrete strength. When the ratio of reinforcement rising by 50%, 100% and 150%, the ultimate load increased by 15%, 29% and 38%, respectively, while the recorded deflection at ultimate load decreased by 7%, 16% and 24%, respectively. For the ultimate load of the studied beams, outcomes exhibited that the equations of the American code ACI 440.1R give very close values with the test values, while they give very conservative values to the deflection at ultimate load which are smaller than the test values by about (37%-45%)

Fresh and hardened properties for a wide range of geopolymer binders – An optimization process

The objective of this study was to identify the optimal geopolymer binder compositions produced from local industrial by-products and compare them with commercially available materials. The first part investigated the optimal binder composition by studying 27 mixtures. In this part of the research, three series of binders were created: the first series of 18 mixtures was Na-based fly ash-slag, the second series consisted of 8 mixtures of K-based fly ash-slag, and the third series were a mixture of metakaolin-slag based geopolymer. The compressive strengths of the mixtures at the age of seven days ranged from 2.18 to 96.23 MPa. The strength development is clearly defined by the components and proportions of the blends. Geopolymers reach about 80% of their 28-day strength in seven days. The 25% water content was optimal for slag-fly ash geopolymers. The strength of the material increased from 68.08 to 96.23 MPa when the Blaine surface area of the slag increased from 3500 to 4500 cm2/g. The optimal proportions of the alkali solution were the intermediate ratios: SiO2/Na2O = 2.0 and SiO2/K2O = 1.5. In the case where Visonta fly ash is prepared for blending, the fly ash content can be maximized by 30%–50% in addition to the blast-furnace slag. In the second part of the research, mortars were prepared from the selected binders: 4 mixtures were prepared with two different binders. In one of these mortars, the solid part of the binder consisted of local raw materials originating from Hungary. This mixture was prepared with 43 m% fine aggregates. The optimal composition of the tested 27 binders tested was selected as the geopolymer matrix for the production of three further mortar mixtures. In these geopolymer mortars, 55, 65, and 75 m% of aggregate applied. The flowtable values of fresh mortars decreased when the proportion of sand increased. The lower the additive content was, the higher the strength of the geopolymer mortar. The 28-day compressive strengths of filtered fly ash-slag mortar sample with 55%, 65%, and 75% of fine aggregate (F–S-a55, F–S-a65, and F–S-a75) made with the selected optimised filtered fly ash-slag geopolymer binder of group A-I.3 (F–S-A-I.3) varied between 11.39 and 40.15 MPa, whereas the Visont fly ash-slag mortar sample with 43% of fine aggregate (V–S-a43) has been 25.05 MPa. For 28 days, the density ranged between 1870 and 2204 kg/m3. The V–S-a43 is found to be the lowest-density blend. The chloride migration test revealed that geopolymer mortars with higher slag content have higher resistance to Cl− ions

A Review of Optimization Algorithms in Solving Hydro Generation Scheduling Problems

The optimal generation scheduling (OGS) of hydropower units holds an important position in electric power systems, which is significantly investigated as a research issue. Hydropower has a slight social and ecological effect when compared with other types of sustainable power source. The target of long-, mid-, and short-term hydro scheduling (LMSTHS) problems is to optimize the power generation schedule of the accessible hydropower units, which generate maximum energy by utilizing the available potential during a specific period. Numerous traditional optimization procedures are first presented for making a solution to the LMSTHS problem. Lately, various optimization approaches, which have been assigned as a procedure based on experiences, have been executed to get the optimal solution of the generation scheduling of hydro systems. This article offers a complete survey of the implementation of various methods to get the OGS of hydro systems by examining the executed methods from various perspectives. Optimal solutions obtained by a collection of meta-heuristic optimization methods for various experience cases are established, and the presented methods are compared according to the case study, limitation of parameters, optimization techniques, and consideration of the main goal. Previous studies are mostly focused on hydro scheduling that is based on a reservoir of hydropower plants. Future study aspects are also considered, which are presented as the key issue surrounding the LMSTHS problem