The Use of Basalt Aggregates in Concrete Mixes in Jordan

The purpose of this research is to investigate the feasibility of using basalt aggregates in concrete mixes. The researcher has designed an elaborate experimental program that included a variation of basalt percentages in concrete mixes. The laboratory investigation included measurements of compressive strength, indirect tensile strength, flexural strength, thermal conductivity, permeability, shear strength and modulus of rupture. A conventional limestone mix was used as a control mix. The results of this investigation indicate a general improvement in mix properties with the introduction of basalt aggregates in the mix

Comparison between Composite Beam of Limestone and Basalt Concrete

The purpose of this study is to investigate the effect of limestone and basalt content in steel-concrete composite beams. An experimental program is set up to test the effect of basalt content on the behavior of composite beams. The properties measured in this research are the deflection of the composite beams, bonding between steel and concrete, compressive strength, flexural strength and load-strain curves for both negative and positive strain. In addition, theoretical analysis or comparison was conducted to validate experimental results. The results show significant improvement in composite beams rigidity and strength as the percentage of basalt increases in the composite beam. Deflection decreased by about 36% to 51%, bond stress increased by 28% to 63%, compressive strength increased significantly from 9% to 43% and flexural strength of the composite beam increased from 5% to 23 when the percentage of basalt was increased from 0 to 100%. The negative strain in compression in the top fiber decreased from 56% to 26% as basalt percentage was increased from 0% to 100%. However, the positive strain in tension for the bottom fiber also decreased from 43% to 17%. Validation of results through theoretical computation was conducted for comparison purposes. It was determined that composite beams were stiffer than limestone in most cases

Torsional Strength of Reinforced Concrete Beams with Brine and Olive Oil Mill Wastewater

The authors conducted a comprehensive research study on adding olive oil mill and brine wastewater to the concrete mix to investigate torsion, bending stress, shear, and compressive strength. The total number of specimens were 33 beams 100 mm (depth) × 100 mm (width) × 500 mm (length). Three beams were used as control samples, and thirty beams were divided into two groups: fifteen samples were from an olive oil mill, and the other fifteen were brine wastewater with different percentages of additive material (olive oil mill and brine wastewater), with 2.5, 5.0, 7.5, 10.0, and 15.0 % of each. The beams were reinforced with 4 ϕ 8 mm as longitudinal steel bars and ϕ 4 mm stirrups spaced at 20 mm. All specimens were tested at 28 days. It was found that the torsional strength of the samples containing brine wastewater when added at the best percentage, which is 10%, was 5.46 MPa. As is the case when adding olive oil mill wastewater with the best percentage, which is 7.5%, it was 5.16 MPa. These data are greater than the torsional strength in the reference samples, which were 4.38 MPa, meaning that the torsional strength when adding brine wastewater and olive oil mill wastewater increases by 24% and 17%, respectively. Doi: 10.28991/CEJ-2023-09-03-012 Full Text: PD

Studying the Flexural Behavior of Reinforced Concrete Beams under the Effect of High Temperature: A Finite Element Model

The strength of concrete elements can be greatly affected by elevated temperature as in fires, and so a great concern must be taken regarding its behavior under such condition. In this paper, a finite element model was built up using ABAQUS software to investigate the flexural behavior of reinforced concrete (RC) beams subjected to service load under elevated temperature. The beam was simply supported and was loaded at one-third and two-third of span length. The study consisted of three RC beams models; the first model simulated a control beam specimen at ambient temperature 20℃, while the other two models demonstrated damaged beams specimens according to two high temperatures 400℃ and 800℃, respectively. Each RC beam had 2 m span length, 300 mm height and 200 mm width. The steel reinforcement configuration was 3∅16 mm (Grade 60) main bars at the positive moment region in the beam bottom, 2∅14 mm (Grade 60) secondary bars at the beam top, and ∅10 mm /150 mm closed stirrups. The model was validated by comparing its results with the theoretical results from ACI code and literature. Several mechanical properties were investigated including concrete compressive strength, modulus of elasticity, and reinforcing steel yielding strength. The test results showed a reduction in the flexural capacity of the RC beams, tested at 400℃ and 800℃, of 17.6% and 88.2%, respectively, with respect to the control beam. The maximum service load carried by the beam, at one-third and two-third of the span length, decreased by 17.1% and 88.1% for the 400℃ and 800℃ high temperature, respectively. The results also showed an increase in deflection when the temperature increased due to the loss in stiffness

Compressive Strength of Jordanian Cement Mortars

Mortars have been prepared from six cement Jordanian brands and tested for their compressive strengths at 2, 7 and 28 days. The strength has been related to some physical parameters. It has been concluded that the compressive strength and its development with age has some variations between the different cement brands. There is an inverse linear rela-tionship between compressive strength and water absorption, and a weaker positive relation with density. There is no clear relation between consistency and compressive strength. Inverse linear relations exist between less than 63 microns size fraction and strength. To account for the differences in compressive strength at different ages and using different cement brands, it is very important to identify the type and amount of cement mineral phases using concrete petrogra-phy and X-ray diffraction and fluorescence techniques