This paper presents the finite element (FE) analysis of double-bolt shear-out (DBSO) fracture failure. The DBSO fracture shape consists of two oppositely: inclined outer main shear fractures, inner main shear fracture, outer shear lips, and curved inner curved fractures. The DBSO begins with two outer main shear fracture initiations under shear, vertical compressive bending, and sideways bending deformations/stresses followed by the two inner main shear fracture initiations under shear and vertical compressive bending deformations. The outer shear lips occurred under vertical compression bending, shear, and sideways tensile bending stresses/deformations while the two inner curved fractures occur under rotational deformation.

Adobe or mud brick building technique is an ancient technique dating back at least to 8300 BC. The oldest continually inhabited structures in the world are made in adobe. Adobe brick have revealed many advantages such as low cost, simple construction, excellent thermal and acoustic properties. Dispute these advantages, adobe buildings experience many problems, like water effect and low brick strength, among others. The objective of this study was to assess the strength of adobe brick made from natural soils and stabilized using laterite, fine sand and fibrous grass. The study first checked the quality of all used materials components, and then with reference to the USCS, the classification and quality of those materials were determined. Afterwards, the controlling brick sample made of natural soil, and the stabilized brick made of natural soils with stabilizers were manufactured using the mix ratio of 50% natural soil, 30% of laterite, 15% of fine sand and 5% of fibrous grass. After the bricks curing, the compressive strength test was performed. It was observed that the adobe brick strength was improved from 1.04 N/mm2 to 2.128 N/mm2 after its stabilization. Further studies were recommended regarding the improvement of adobe bricks performance using other soils mixture content, or other types of stabilizers with target to achieve the strength of stabilized soil bricks with cement or even the strength of burnt bricks.

The development of local construction industry has resulted in the high demand for cement, used not only for structural but also non structural applications, such as finishing. As a consequence cement has been far from being an affordable material for the good part of the population, especially in the rural areas where financial means are still limited. Regarding the finishing exercise, those people have been using soil mortar alone or reinforced with grasses without any strategy about mixture content. The objective of this study was to assess the performance of cohesive soil mortar mixed with cow dung and establish recommended mix content for plastering works. Twelve samples of soil mortar with 10%, 20%, 30% and 40% of cow dung, were prepared and subjected to drying period of 28 days before they were tested for water absorption, shrinkage, weathering resistance, specific gravity and Atterberg limit tests. The tests showed good results for checked properties with 20% of cow dung, and therefore it could be considered as a low-cost alternative plastering material to cement mortar for some structural members under normal weather conditions. In order to avoid the earlier shrinkage and cracks in this mortar due to spontaneous drying by sun, the mortar should be protected and not be left in open area at earlier stage. Keywords: Cohesive Soil, Cow dung, Mortar, Shrinkage, Water absorption, Weathering resistance

The waste generation from old rubber tires has been increasing and causing environmental degradation with the escalation of vehicles number especially in the cities. Bitumen is extensively used in flexible pavement construction and as its manufacturing industries were still growing, the cost has not been much affordable. This study aimed at evaluating the possibility of a partial replacement of ordinary bitumen by tire rubber waste, with the purpose to reduce not only the amount of rubber wastes dispersed in the nature, but also the material cost, while keeping or improving the bitumen product performance. The study used rubber waste powder as partial replacement to ordinary bitumen by 5%, 10%, 15%, and 20% of its weight and, with adequate samples, properties of the bitumen product were investigated, after checking the standard quality of used bitumen 60/70 grade. It was established that more adequate results were achieved at 5% of replacement, which showed the penetration value of 61.66 tenths mm, the softening point value of 52.750C, and the viscosity of 134 sec. Regarding the cost estimation of this new bitumen, a cost reduction of around 5.3% was realized. Therefore, the use of rubber waste powder would contribute not only to the reduction of the quantity of respective waste in the environment, but also influence on the material affordability. The use of other grades of bitumen than 60/70, as well as the strength and durability performance may be a good scope for further studies.

Worldwide, the medium density fiberboard (MDF) materials have been extensively used for furniture as well as a normal building material. The MDF production is based on wood materials that are obtained from the tree cutting, and this process may conduct to gradual deforestation. Different works have shown the advantages of using other renewable biomass sources for MDF manufacturing. This study aimed at assessing the potential of using the African couchgrass, as one of worldwide available grass, and which has been one of the most worrying weeds for agriculture areas. The test with the manufactured MDF checked such material properties like density, moisture content, water absorption, and thickness swelling. The established results were 727.143 kg/m3, 5.81%, 9.18%, and 7.6% respectively. All those results are in the range of standard values recommended by ASTM D1037, and they give optimism for the application of couchgrass in the manufacturing of MDF. This new material was planned to be used as a partition component. Therefore, further studies should evaluate other important properties, like fire and sound resistance, while a proposal for potential replacement of the used industrial wood glue is also welcome.