Dr. Saeed Khalaf Rejeb د. سعيد خلف رجب -

Gender	MALE
Place of Work	Polytechnic College Mosul
Position	Assist. Prof.
Qualification	Ph.d
Speciality	Civil Engineering, Concrete Technology
Email	saeed_kh@ntu.edu.iq
Phone	07702022048
Address	Northern Technical University, Mosul Technical Institute, Civil Technologies Department, Assist. Prof., Mosul, Iraq

The Effects of Waste Ceramic Powders and Waste Glass Powders on the Rheological and Mechanical Properties of Self-Compacting Concrete

May 5, 2024

Journal Tikrit Journal of Engineering Sciences

publisher Tikrit Journal of Engineering Sciences

DOI https://doi.org/10.25130/tjes.31.2.7

Issue 2

Volume 31

Two key axes dominated this experimental research. The first was developing self-compacting concrete from ceramic waste powder (CWP) and glass waste powder (GWP), which met and followed the recommended European specification and guidelines for self-compacting concrete (EFNARC) standards. The second axis indicated the self-compacting concrete's rheological and mechanical performance. Sixteen different mixtures were produced using supplementary cementitious materials (SCMs) to replace cement partially. The replacement levels of SCMs were 5%, 10%, and 15% (by weight of cement), divided into three series: Series A (containing ceramic waste powder), Series B (containing glass waste powder), and Series C (containing combinations of ceramic waste powder and glass waste powder). The SCC rheological properties for all mixtures with different levels of SCMs replacement in the mixture gradually decreased as the substitution ratios increased. The reduction in flowability for substitution, ranging from 5% to 35%, was approximately 0% to 12%, respectively. However, the reduction was insignificant; the fresh properties remained within the limits specified by EFNARC. Regarding the mechanical properties, at an early age, the strength of mixtures decreased with increasing alternative ratios. However, after 90 days, the strength increased by about 11% and 9% of the compressive and flexural strengths, respectively, over the control mix, indicating that SCMs improve the concrete strength over time and are suitable to contribute to an eco-friendly concrete industry without compromising strength.

Read Publication

Proportioning of the mortar phase of self-compacting concrete by using binary and ternary cementitious materials

Dec 15, 2023

Journal AIP Conference Proceedings Volume 2862: (2023)

publisher AIP Conference Proceedings

DOI https://doi.org/10.1063/5.0171433

Issue 1

Volume 2862

The main aim of this study is to develop a sustainable self-compacting-equivalent mortar by partial replacement of cement with supplementary cementitious materials (SCMs) such as ceramic waste powder (CWP) and glass waste powder (GWP). The replacement levels of SCMs are 5%, 10% and 15% (by weight). A total of sixteen mixes were cast, including a control mix, three mixes each for GWP and CWP, and nine mixes for a combination of GWP and CWP. Two tests were done in the fresh state: slump flow and flow time. The compressive strength, flexural strength, and ultrasonic pulse velocity (UPV) of equivalent mortar mixes were tested to investigate their hardened properties. The beneficial influence on fresh characteristics was measured using GWP and CWP, and the majority of the values were observed to be within an acceptable range according to the EFNARC standard. The equivalent mortar mix prepared with a combined usage of 5% GWP and 5% CWP (i.e., 5-5-2 mix) demonstrated the greatest strength, which increased to 20% more than the reference strength. The increased SCC performance was mostly due to SCMs pozzolanic behavior and finer particle size, as well as better filling property. The study indicated that CWP could be used up to 5% and GWP could be used up to 10% as a partial replacement of cement in SCC, respectively. which not only reduces costs but also provides sustainability.

Read Publication

Properties of High-Strength Concrete Containing Polypropylene and Glass Fibers

Nov 8, 2022

Journal AIP Conference Proceedings 2394, 040032 (2022)

publisher Published by AIP Publishing. 978-0-7354-4243-6/$30.00

DOI https://doi.org/10.1063/5.0121795

Issue 1

Volume 2394

High strength concrete (HSC) posses more problems, since it has less ductility in comparison with normal strength concrete (NSC). To overcome this problem was reinforced with fibers and hybrid fibers. The effects of fibers and hybrid fibers upon the properties of high-strength concrete mixtures containing superplasticizing admixtures have been investigated. The properties of fibrous high-strength concrete and high-strength concrete are compared. Results showed that decrease in workability of all concrete mixtures containing polypropylene, glass and hybrid fibers compared with control mix. It was found that the addition polypropylene fibers increase the suitable w/c ratio to save the workability from 0.24 to 0.26, 0.27 and 0.29 at 0.5, 1.0 and 1.5 volume fraction respectively. While the w/c ratio increased to 0.35 when the 0.4% glass fiber was added. HSC with 1.5% polypropylene fibers showed superior splitting and flexural strengths over the other concrete without or with fibers, compared with HSC without fibers the increasing were 30.76% and 25.61% respectively. At 28-day age, fibrous high-strength concrete showed higher compressive, splitting and flexural strengths than the high-strength concrete, depending upon the types and volume fraction of fibers. The results obtained demonstrate that the addition of the hybrid fibers to the high strength concrete showed that the ratio of (0.7% polypropylene + 0.12% glass fibers) at volume fraction 0.82% gives better fresh and hardened properties than the ratio (0.3% polypropylene + 0.28% glass fibers) at volume fraction 0.58%. The maximum increase in compressive strength, splitting strength and flexural strength of high strength concrete contains (0.7% polypropylene + 0.12% glass fibers) were 9.57%, 15.38% and 14.04% respectively.

Read Publication

Strength performance of alkali activated structural lightweight geopolymer concrete exposed to acid

Mar 1, 2022

Journal Ceramic International

publisher sciencedirect

DOI https://doi.org/10.1016/j.ceramint.2021.11.240

Issue 5

Volume 48

This study investigates the performance of structural lightweight geopolymer concrete (SLWGC) exposed to chemical attack. The objective of this study is validation the ability of using light weight geopolymer concrete for structural purpose under hard conditions. The alkali activator was produced using sodium silicate, sodium hydroxide and water. Flay ash and slage as waste materials were replaced by 90% of ordinary Portland cement to produce the geopolymer concrete. Also, ordinary cement concrete produced to comparison. Three types of lightweight aggregate were used instead of normal aggregate represented by pumice stone, expanded clay and construction waste clay brick to produce SLWGC. The unit weight of produced SLWGC were in the range (1800–2100) kg/m3. Normal weight geopolymer concrete and SLWGC were produced simultaneously to compare their performance each with other. The geopolymer concrete mixes treated by heat curing at 65 °C for 24 h after removing the molds. The specimens of all mixes exposed to sulfuric acid with concentration 5% and 10% for 8 weeks. The investigated mechanical properties represented by compressive strength and flexural tensile strength. The results indicate that the geopolymer concrete exhibit better resistance for acid attack compared to OPC concrete where the strength deterioration for SLWGC lower than ORC light weight concrete after exposed to acid, crushed clay bricks exhibit superior mechanical and durability performance compared to other LWA. Finally, the results proved the ability of producing light weight geopolymer concert for structural purposed with acceptable performance of strength and durability under hard chemical conditions.

Read Publication