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Elasto-plastic deformation and failure
Published in M.L. Jeremic, Rock Mechanics in Salt Mining, 2020
The unconfined compressive strength test is most common for determination of salt strength. The test is exposed to the uniaxial loading of a cylinder or prism of salt to failure. The salt specimens usually fail in shear, as indicated by the characteristic cones formed on the conjuncted planes of failure. The compressive strength so obtained depends to some degree on a certain number of variable factors such as the sample shape, size, porosity, moisture, mineral composition and others. Further consideration of unconfined compressive strength in regard to three factors is discussed. The relationship between size effects and strength has been studied since the end of the last century by some investigators. Their investigations suggest a number of seemingly different predictive equations.
Stress and strain
Published in William Bolton, Engineering Science, 2020
The compressive strength is the maximum compressive stress the material can withstand without becoming crushed. The unit of strength is that of stress and so is the pascal (Pa), with 1 Pa being 1 N/m2. Strengths are often millions of pascals and so MPa is often used, 1 MPa being 106 Pa or 1 000 000 Pa. Typically, carbon and low alloy steels have tensile strengths of 250 to 1300 MPa, copper alloys 80 to 1000 MPa and aluminium alloys 100 to 600 MPa.
Materials and components for masonry
Published in Peter Domone, John Illston, Construction Materials, 2018
Clay bricks probably have the widest range of strengths of any of the manufactured masonry materials, with compressive strengths ranging from 10 MPa for an under-fired soft mud brick to as much as 200 MPa for a solid engineering brick. The common shapes and terminology are shown in Fig. 33.1. The compressive strength is measured by a crushing test on whole units with the stress applied in the same direction as the unit would be loaded in a wall. Solid and perforated units are tested as supplied, but frogs are normally filled with mortar as they would be in a wall. The European test method EN772-1 (2000) uses either mortar capping or face grinding to achieve even loading. The quoted strength is the average of six to ten determinations of stress based on the load divided by the area of the bed face. The flexural strength and modulus of elasticity are not normally designated test parameters in unit standards, but it is important to obtain data for finite element analysis models. A standard three-point bending method is included in RILEM LUM A.2 (1994), with linear elastic analysis used for the calculation of the maximum flexural stress.
Effects of biocementation on some properties of cement-based materials incorporating Bacillus Species bacteria – a review
Published in Journal of Sustainable Cement-Based Materials, 2019
Karanja D. Mutitu, Mulwa O. Munyao, Muthengia J. Wachira, Romano Mwirichia, Karanja J. Thiong'o, Mwiti J. Marangu
Compressive strength is the capacity of a material or structure to withstand loads tending to reduce size. Several studies have documented compressive strength improvements on bacterial containing cementitious material of between 9% and 25% by 28th day of curing [38,60]. Different researchers have documented both positive and negative effects on compressive strength depending on bacterial strain, cell concentration or concrete age [38,61]. These nutrients affect compressive strength and cement hydration. Wang [23] found out that calcium nitrate as a bacterial nutrient accelerated cement hydration while yeast extract significantly delayed the hydration and resulted in a lower hydration degree at the 7th day of curing and a reduced compressive strength at the 90th day of age.
Feasibility of transforming lightweight aggregate made of pulp and paper mill sludge into insulating concrete
Published in Journal of the Chinese Institute of Engineers, 2020
Compressive strength is a crucial index for the resource recovery of sintered aggregates and is decided by aggregate components. Factors affecting compressive strength can be porosity, pore size, and crystallization type and pattern; these factors affect one another. Moreover, molding pressure can affect compressive strength (Feng 2002).The compressive strength of lightweight aggregates varies with raw materials. The strength ranges between 20.8 and 880 kgf/cm2. Aggregates with high strength can be used to manufacture construction materials, whereas those with low strength can be adopted to produce nonconstruction materials.
Thermal behavior of acidic and alkali activated laterite based geopolymer: a comparative study
Published in Geosystem Engineering, 2022
Raphael Belinga Essama Boum, Francois Mvondo Owono, Cyriaque Rodrigue Kaze, Juste Constant Essomba Essomba, Bakary Souleymanou, Juvenal Giogetti Deutou Nemaleu, Marie Joseph Ntamak-Nida
Compressive strength is measured during the crushing of 28-day-old specimens, respectively, untreated and treated at 200°C, 400°C, 600°C, 800°C and 1000°C. The test consists in subjecting the specimens to a continuous and progressive load using an ELE International hydraulic press until they are crushed. The compressive strength is the ratio of the breaking load to the cross-sectional area of the specimen, calculated from the relationship: