Papers by Mostafa A . Masoud
Construction and Building Materials, 2021
h i g h l i g h t s Incorporated boric acid hindered the cement hydration in serpentine concrete.... more h i g h l i g h t s Incorporated boric acid hindered the cement hydration in serpentine concrete. Boric acid addition increased water absorption and porosity of serpentine concrete. Boric acid had deleterious effects on the ITZ and strength of serpentine concrete. Boric acid enhanced the thermal and fast neutron attenuation of serpentine concrete. c-Ray attenuation of serpentine concrete was diminished by boric acid addition.
h i g h l i g h t s Incorporated boric acid hindered the cement hydration in serpentine concrete.... more h i g h l i g h t s Incorporated boric acid hindered the cement hydration in serpentine concrete. Boric acid addition increased water absorption and porosity of serpentine concrete. Boric acid had deleterious effects on the ITZ and strength of serpentine concrete. Boric acid enhanced the thermal and fast neutron attenuation of serpentine concrete. c-Ray attenuation of serpentine concrete was diminished by boric acid addition.
Landslides are one of the natural hazards, which have significant negative effects on both humans... more Landslides are one of the natural hazards, which have significant negative effects on both humans and the environment. Thus, slope stability analyses and stabilization processes are necessary to obviate or mitigate landslides. In this study, the effect of groundwater level fluctuations and the construction of a building (i.e., a recently built church) on slope stability was investigated on the eastern slope of the Avas Hill, at Miskolc, in Northeast Hungary. Soil movements and groundwater levels were monitored and geological and slope stability models were constructed. Furthermore, the possibility of constructing a retaining system was evaluated to minimize the detrimental effects of both groundwater level fluctuations and the construction of the church. The findings showed that the fluctuation in groundwater levels had a destructive effect on slope stability due to porewater pressure, which decreased the soil strength of the slope and slope stability. On the other hand, the church added an external load onto the underlying soil leading to an increase in slope instability. Hence, we suggested constructing retaining structures such as gravity retaining walls to increase the soil shear strength and enhance slope stability in the long term.
h i g h l i g h t s Radiation attenuation properties are investigated for ABC, LBC and CBC. NXcom... more h i g h l i g h t s Radiation attenuation properties are investigated for ABC, LBC and CBC. NXcom program results have an excellent agreement with the experimental data. Serpentine-associating minerals affect radiation attenuation properties. High dolomite ratio turns LOI to a false index for the internal-crystalline water. ABC reveals the best attenuation properties against fast neutrons and c-rays. a b s t r a c t Antigorite, lizardite, and chrysotile are the most important polymorphs of serpentine. In this work, we investigate the physical and radiation shielding properties of three serpentine concrete mixes containing the three serpentine polymorphs. The physical properties were evaluated in terms of density, water absorption and porosity. The shielding characteristics against fast neutrons and c-rays were determined. Attenuation measurements were conducted via the transmission method using a PuBe neutron source, which was utilized as a mixed-field source for fast neutrons and c-rays over the energy regions of 0.8-11 and 0.4-8.3 MeV, respectively. The experimental data were compared with the NXcom program results, and an excellent agreement was observed. This study showed that the antigorite-based concrete has a relatively higher attenuation efficiency against c-rays and fast neutrons compared with the lizardite-and chrysotile-based concretes. This finding is discussed in terms of the effects of minerals associated with serpentine, namely dolomite (CaMg(CO 3) 2) and magnetite (Fe 3 O 4). Further, the contributions from dolomite should be considered for the precise determination of loss on ignition (LOI). These results suggest that associated minerals with serpentine aggregates can lead to a significant variation in the efficiency of c-rays and fast neutrons shielding of serpentine concretes.
h i g h l i g h t s Barite and hematite replaced serpentine by 25 and 50% of its concrete volume.... more h i g h l i g h t s Barite and hematite replaced serpentine by 25 and 50% of its concrete volume. Unlike barite, hematite increased the porosity of serpentine concrete (A) Barite and hematite decreased the mechanical strength of concrete A. 25% hematite revealed the highest Rth for concrete A. 50% barite showed the highest c-ray attenuation properties for concrete A. a b s t r a c t To highlight the impact of barite and hematite addition on selected physical, mechanical, and radiation attenuation properties of serpentine concrete (A), different replacement ratios of barite and hematite aggregates (25, and 50% by volume) were used separately. The physico-mechanical properties of the prepared serpentine-barite (AB25, 50) and serpentine-hematite (AH25, 50) concrete mixes compared to those of the control (A) were evaluated. The radiation shielding properties of these concrete mixes against both c-ray and thermal neutrons were experimentally measured. The linear attenuation coefficient of c-ray, m, and thermal neutron attenuation coefficient, Ʃ th , were determined experimentally by the transmission method in a fine beam geometry setup using 60 Co c-ray source and a moderated PuBe source, respectively. The experimental results of c-rays were verified by the correlation with the theoretical data obtained by the WinXCom program. Besides, many c-ray attenuation parameters, such as a half-value layer, HVL, single-valued, and energy-dependent effective atomic number, Z eff , as well as effective electron density, N eff , were determined. It was found that the addition of barite and hematite aggregates to serpentine concrete increased its bulk density, and decreased its mechanical strength. Moreover, unlike barite, the hematite increased the water absorption and porosity of concrete. In conclusion , this study revealed that the prepared hematite-and barite-serpentine concrete mixes, except for AB50, have acceptable mechanical properties with enhancing radiation shielding performance.
To modify some properties of serpentine-based concretes, serpentine aggregate (S) was partially r... more To modify some properties of serpentine-based concretes, serpentine aggregate (S) was partially replaced with either hematite aggregate (H) or barite aggregate (B) at levels of 25% and 50%, by volume. To evaluate the impact of these aggregates, selected physical properties of the prepared serpentine-barite (AB 25 , 50) and serpentine-hematite (AH 25, 50) concretes were measured and compared to those of the control serpentine concrete (A). In addition, the fast neutrons and gamma-rays shielding properties of these concretes in comparison with those of the control (A) were experimentally measured using a 239 Pu-Be source and stilbene detector. These shielding properties were determined by measuring the neutron and gamma-ray attenuation coefficients (Σ R ðE n Þ and μðE γ Þ, respectively), as well as parameters of relaxation length (λ) and half value length (HVL) at different energies. It was found that incorporation of B and H had a negative impact on the physical properties of the serpentine-based concretes except for density. On the other hand, this incorporation improved the attenuation properties of serpentine-based concretes. This improvement was more effective in the case of using B rather than H in the equivalent ratios. Finally, 50% B was the best ratio in enhancing the shielding of fast neutrons and gamma-rays.
This work is the first attempt to study the
possibility of incorporating three different types of... more This work is the first attempt to study the
possibility of incorporating three different types of
Egyptian serpentine aggregates (antigorite, lizardite
and chrysotile) with different serpentinization grades
as fine and coarse aggregates for normal concrete
production. The results of physical and mechanical
tests for each type of aggregate were compared to the
others. In addition, the effect of serpentinization grade
on their mineralogical composition, physico-mechanical
and morphological properties of was evaluated
and compared. The results were analyzed by using
sophisticated tools such as X-ray diffraction, thermogravimetry/
differential thermogravimetry and
scanning electron microscopy. The results revealed
that the physical, mechanical and microstructural
properties of serpentine-based concretes were negatively
influenced by the progress of serpentinization
and deformation processes. The antigorite aggregate
showed the lowest serpentinization grade compared to
the others (i.e. lizardite and chrysotile). Thus, the
antigorite-based concrete revealed better physical and
mechanical properties as well as a condensed interfacial
transition zone than those of lizardite- and
chrysotile-based. Therefore, the results of this study
indicated that antigorite is the most appropriate
serpentine aggregate to be used in normal concrete
production, however, more tests on the durability of
such concrete are needed
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Papers by Mostafa A . Masoud
possibility of incorporating three different types of
Egyptian serpentine aggregates (antigorite, lizardite
and chrysotile) with different serpentinization grades
as fine and coarse aggregates for normal concrete
production. The results of physical and mechanical
tests for each type of aggregate were compared to the
others. In addition, the effect of serpentinization grade
on their mineralogical composition, physico-mechanical
and morphological properties of was evaluated
and compared. The results were analyzed by using
sophisticated tools such as X-ray diffraction, thermogravimetry/
differential thermogravimetry and
scanning electron microscopy. The results revealed
that the physical, mechanical and microstructural
properties of serpentine-based concretes were negatively
influenced by the progress of serpentinization
and deformation processes. The antigorite aggregate
showed the lowest serpentinization grade compared to
the others (i.e. lizardite and chrysotile). Thus, the
antigorite-based concrete revealed better physical and
mechanical properties as well as a condensed interfacial
transition zone than those of lizardite- and
chrysotile-based. Therefore, the results of this study
indicated that antigorite is the most appropriate
serpentine aggregate to be used in normal concrete
production, however, more tests on the durability of
such concrete are needed
possibility of incorporating three different types of
Egyptian serpentine aggregates (antigorite, lizardite
and chrysotile) with different serpentinization grades
as fine and coarse aggregates for normal concrete
production. The results of physical and mechanical
tests for each type of aggregate were compared to the
others. In addition, the effect of serpentinization grade
on their mineralogical composition, physico-mechanical
and morphological properties of was evaluated
and compared. The results were analyzed by using
sophisticated tools such as X-ray diffraction, thermogravimetry/
differential thermogravimetry and
scanning electron microscopy. The results revealed
that the physical, mechanical and microstructural
properties of serpentine-based concretes were negatively
influenced by the progress of serpentinization
and deformation processes. The antigorite aggregate
showed the lowest serpentinization grade compared to
the others (i.e. lizardite and chrysotile). Thus, the
antigorite-based concrete revealed better physical and
mechanical properties as well as a condensed interfacial
transition zone than those of lizardite- and
chrysotile-based. Therefore, the results of this study
indicated that antigorite is the most appropriate
serpentine aggregate to be used in normal concrete
production, however, more tests on the durability of
such concrete are needed