Bricks whose solid ingredient is 100% fly ash have been manufactured. The manufacturing process uses techniques and equipment similar to those used in clay brick factories. The bricks produced were about 28% lighter than clay bricks. The bricks manufactured from fly ash possessed compressive strength higher than 40 MPa. This exceeds some of the best of load carrying clay bricks available by mor...

A nonlocal generalization of Weibull theory is presented to predict the probability of failure of unnotched structures that reach the maximum load before a large crack forms, as is typical of the test of modulus of rupture. The probability of failure at a material point is assumed to be a power function of the average strain in the neighborhood of that point. For normal sizes, the deterministic...

A copula-based approach is used to estimate the dependence among three lumber strength properties: modulus of elasticity ( MOE ), rupture MOR and ultimate tensile UTS ). are destructive measurements so they cannot be obtained simultaneously for specimens. The modeling possible under an appropriate experimental design with i) a shoulder group rupture, ii) tension, iii) other groups proof loaded ...

The effect of growth rate on weight density and strength properties of three Norway spruce cutting clones growing on three different sites in different geographic locations was studied. The purpose was to follow variation in wood physical and mechanical properties and in quality between fast-growing clones grown in environments differing in nutritional and soil properties and climate within the...

Numerical simulation is used to explore the behavior of concrete beams of different sizes and different notch lengths, loaded in three-point bending. The entire range of notch depth is studied. One limit case is type 1 fracture, which occurs when the notch depth is zero and the crack initiates from a smooth surface (this is the case of the modulus of rupture test). Another limit is type 2 fract...

The objective of this research was to investigate the utilization of olive mill sludge (OMS) as an alternative to wood in the manufacture of the medium density fiberboard (MDF). The MDF panels were manufactured using standardized procedures that simulated industrial production at the laboratory. Six panel types were made from various mixtures of hardwood fiber/dried OMS flour, 100/0, 90/10, 80/...

A HALF-PLANE CRACK propagates dynamically, nominally in the x direction. along the plane _V = 0 in an unbounded solid subjected to remote loading equivalent to a static stress intensity factor K*. The crack front at time t lies along the arc x = c,,t+a_/‘(z, t) where a,) is a constant velocity, J’(z, t) is an arbitrary function, and E is a small parameter. The crack front speed thus varies alon...

7 Soil structure is often said to be the key to soil productivity since a fertile soil, with desirable 8 soil structure and adequate moisture supply, constitutes a productive soil. Soil structure 9 influences soil water movement and retention, erosion, crusting, nutrient recycling, root 10 penetration and crop yield. The objective of this work is to study, humic acid (HA) 11 application on some...

This paper examines the feasibility of using calcium-based biocement to form an impermeable crust on top of a sand layer. The biocement used was a mixture of calcium salt, urea, and bacterial suspension, which hydrolyzed urea with production of carbonate and an increase of the pH level. Applying 0.6 g of Ca per c m 2 of sand surface, the permeability of the biocemented sand can be reduced from ...

the application of stepwise multivariate-linear regression models for determination of particleboard properties based on structural factors was studied. poplar (populus alba), beech (fagus orientaleis) and hornbeam wood (carpinus betulus) with dry density of 460, 630 and 790 kg/m3,respectively, were used as raw materials. three levels of boards target density (520, 620 and 720 kg m-3) and urea ...