Comparison between Composite Column Using Limestone and Basalt Concrete

This research is conducted to study the experimental behavior of composite steel-concrete columns with basalt additives. Various percentages of basalt are added to the concrete mixes to investigate its effect on the total axial compressive capacity of the columns. Expected failure scenarios of the columns are: concrete compressive failure, buckling of steel section, and de-bonding between steel and concrete sections. A conventional limestone composite column was used as base mix. The results of the study indicate a significant improvement in structural behavior and strength of the columns by increasing the percentage of basalt content.

The Use of Fine Blast Furnace Slag in Improvement of Properties of Concrete

Concrete properties can be improved using Fine Blast Furnace Slag (BFS). The latter was used to replace cement in concrete at 10%, 15%, 20%, 25%, and 30% proportions and properties of both fresh and hardened concrete improved. Best workability (evaluated by slump and Table tests) was recorded at 30% of BFS addition. VEBE-time, an indication of workability of concrete, decreased to its lowest value (about 4 seconds at 30% BFS) and compaction factor attained its maximum value of 99% at BFS 25%. For density and unit weight, 30% of fine BFS in concrete mix resulted in maximum density of 2180 kg/m3 for fresh concrete, and 2430 kg/m3 for hardened concrete. Unit weight of concrete achieved a maximum of 23.9 kN/m3 at 30% BFS has achieved specified strength at 1st week and 28 days, also the late strength is high at 56 and 84 days. Bond and flexure loads come high of BFS use. The data of compressive, bond, and flexural strengths are highly related. Results of research are useful and may be applied using fine BFS to improve the properties of concrete materials.

Inspection and Assessment of Highway Bridges in Jordan along the Desert Highway: A Case Study

Bridges, especially highway bridges, are a key factor in nations’ development and flourish. Thus, great care should be taken to maintain and inspect their safety and serviceability. An immediate repair will prevent the loss of life and vehicles damage while crossing underpass and overpassing the heavy deteriorated bridges. Reinforced or pre-stressed concrete bridge girders become structurally deficient because of severed reasons including, increasing in the load requirements, corrosion of pre-stressing strands or reinforcement bars and collision of over-height trucks with the bulb of the concrete girders. The purpose of this case study is to evaluate and assess the damages of the highway bridges in Jordan. Since there is no mandatory program in Jordan for inspection of bridges and evaluating their conditions, this paper presents an inspection and assessment of two highway bridges along the desert highway which is the essential nerve connecting Jordan cities, and it also serves as an international road between many middle east countries. These two Bridges have never been investigated or checked since their construction in the late 1980s. The study results showed that the main factor causing the deterioration of these bridges is the collision of the over-height trucks with their elements. Relying on the collected data, solutions and repair methods were introduced to rehabilitate these bridges and assure their structural safety.

Dynamic Modulus of Elasticity of Some Mortars Prepared from Selected Jordanian Masonry Cements

In light of the highly demanding cement market in Jordan, comprehensive studies should be undertaken to investigate the properties of the different cement types. This paper studies the Dynamic modulus of elasticity (DME) at 2, 7 and 28 days in mortars using six cement Jordanian types with CaO contents less than that of the ordinary Portland cements. It was found that the DME has strong relation with compressive strength. At the age of 28 days the mortars had some different values of DME. One important result of our work is that DME at the age of 28 days can be derived from those of the two days mixes. To account for the differences in dynamic modulus of elasticity with time, it is highly recommended to study in detail the mortars petrography under the light microscope. Using the scanning electron microscope (SEM), usually with attachment for chemical analysis at the crystal scale, in addition to X-ray diffraction technique may help characterization of the cement phases qualitatively and quantitatively.

Local Aggregate in Production of Concrete Mix in Jordan

Concrete properties such as unit weight and compressive strength are highly dependable on the properties of aggregate. Current research aims to study the effect of aggregate properties on concrete considering the resource of aggregate. The properties of aggregate and fine sand were studied (specific gravity, density, absorption, and abrasion). Also, the properties of concrete were studied (density, unit weight, and compressive strength). Samples of coarse and medium aggregates, and fine sand were collected from different areas in Jordan (Ajloun, Amman, Aqaba, Irbid, Jerash, Karak, Ma’an, Madaba, Salt, Zarqa, and Tafila) to be tested and used in concrete mix. Aggregate from South of Jordan has higher values in specific gravity and bulk density (Aqaba, Ma’an, and Karak aggregates). Also, the same aggregate samples have lower values in absorption and abrasion (Ma’an, Aqaba, Karak, and Tafila). For the properties of concrete that include density, unit weight, and compressive strength, all samples have achieved the design properties and strength in the current study. For density and unit weight, samples from South of Jordan have higher values (Ma’an and Aqaba). And for compressive strength, Ma’an, Irbid and Amman concrete samples have the highest values at 7-day, while the 28-day compressive strength comes highest for Zarqa, Ma’an, Irbid and Amman. From the results of the current study, the compressive strength at 7-day and 28-day is related to the density of coarse and medium aggregate, abrasion, and absorption. The higher the density, the higher the compressive strength. And the lower abrasion and absorption, the higher the compressive strength of concrete. Current research will be useful in selecting the source of aggregate to produce a considerable concrete strength.

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 relationship 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 petrography and X-ray diffraction and fluorescence techniques.