Dr. Emmanuel B. Yamb
University of Bamenda, Republic of Cameroon, P.O Box 8842 Douala, yamb_bell@yahoo.fr;

Dr. Christian A. Bock Hyeng
North Carolina A&T State University, School of Technology, 1601 East Market Street, Greensboro NC, 27411, 336-334-7199, cbhyeng@ncat.edu

ABSTRACT

      Industrial wastes produced from civil engineering projects can lead to severe environmental impacts. One of such waste is heavy metal like mercury (Hg), cadmium (Cd), and lead (Pb) which may have to be disposed of after demolition. However, the disposal of heavy metals at landfills could lead to the migration of metal ions into the surrounding soils, in the form of insoluble hydroxides, such as chromium hydroxides, aluminum hydroxide, iron hydroxides, and thereby posing health risk. Consequently, it is of uttermost importance for heavy metals to be reused in civil construction in order to reduce the volume that could be brought to the landfills or disposal sites. This paper uses analytical concepts to study the ecological, and environmental impacts of heavy metal disposal at landfills, and how their reuse could significantly address the issue of metal leachate into the soil as well as the reduction of its impact on global warming and the environment as a whole. Thus, these heavy metals have been extensively studied and their effect on the environment, and on human health regularly reviewed by international bodies such as WHO with more emphasis on proper discarding of these materials rather than reuse.

An article published inside the International Journal of Materials Engineering and Technology © 2017 Pushpa Publishing House, Allahabad, India
Website:http://www.pphmj.com ; http://dx.doi.org/10.17654/MT016120001
(Volume 16, Numbers 1-2, 2017, Pages 1-20 ISSN: 0975-0444 )

Received: December 20, 2016; Accepted: February 5, 2017

Abstract

       We study the geotechnical parameters (void ratio and hydraulic conductivity) of two types of mixtures of particles (crushed gravel and rounded gravel), and determine the porosity n (or the void ratio e)
along with the permeability or hydraulic conductivity by the weight mass method. A progressive evolution of the void ratio of the three granular classes is established starting with completely crushed gravel to the fully rounded gravel. We establish a dependency of the void ratio in function of the size range for each grain size.
       The study of the permeability or the hydraulic conductivity enables to see a decrease in the evolution of the permeability of different granular classes in function of the shape of the grains. Fully crushed gravels have a higher permeability. We rely on the fact that the values of permeabilities do not follow that of the void ratio and we have established a difference between porosity and drainage which is a function of the stack and grain shape. And then we have established a relationship between the measured values and the predictive values of
Chapuis [4].

Keywords and phrases: void ratio, permeability, rounded gravel, crushed gravel, weight mass.

An article published inside the International Journal of Civil Engineering and Technology (IJCIET)
Website:http://www.iaeme.com/ijciet/issues.asp?JType=IJCIET&VType=8&IType=8 ,
(ISSN Print: 0976-6308 and ISSN Online: 0976-6316 )

Volume 8, Issue 8, August 2017, pp. 1662–1673, Article ID: IJCIET_08_08_181

B. Bahel
Civil Engineering Department, Faculty of Engineering, University of Douala
E. Yamb
Civil Engineering Department, University of Douala
S. Owona and G. E. Ekodeck
Department of geology, Faculty of Sciences, university of Douala

ABSTRACT

          We studied the clogging in the granular layers of drainage formed with the mixing of gravel (rounded and crushed) by leachate from the percolation of solid household waste with clogging index. A series of curves of the clogging index have been plotted according to the constitution of the layer of gravel beginning with one of the curve obtain with the entirely rounded gravel and another with the entirely crushed gravel and the rest from a progressive mixtures of particles of crushed gravel in rounded one. Also we established a relation between the void index or porosity in function of the percentage mixing of rounded gravel and crushed gravel in the various granular layers for drainage. Thereafter a relation between the clogging index, the porosity or
void index and the drainage layers according to the percentage mixing of gravel rounded and crushed were plotted.
       The study on the clogging index allowed us to observe a pattern of the curves depending on the nature of the gravel having identical appearance and some mingled. It is therefore apparent that the sample with 40% of the rounded gravel clogged faster than the others. But what we noted is that the clogging index does not change significantly according to the different types of layers and approaches the results of Blond 2012. Also these results showed us that rationalize management of the gravel can serve as a level to take environmental phenomena in consideration when constructing or exploiting the Center of Storage of the Household Waste (CSHW).

Key words: Clogging index, mixing gravel, Leachate, Waste storage center

An article published inside the International Journal of Emerging Technology and Advanced Engineering
Website: www.ijetae.com (ISSN 2250-2459, ISO 9001:2008 Certified Journal, Volume 3, Issue 6, June 2013)

Emmanuel Yamb¹, Christian Bock Hyeng², François Ngapgue³
1-University of Bamenda, Cameroon; P.O. Box: 8842 Douala, Cameroon
2-North Carolina Agricultural and Technical State University, 1601 E. Market St., Greensboro, NC 27411, USA
3-University of Dschang, Cameroon; P.O. Box: 134, Cameroon

Abstract

The preoccupation with an improvement of constructions in civil engineering leads to the adoption of the more powerful systems according to resistance, safety, the technology of implementation and also to the cost. The calculation of the steel-concrete elements was based beforehand on the experimental established formulae. This article proposes theoretical bases for the calculation of the interior forces, the normal and tangential constraints in the element as well as the acceptable load estimating in the steel-concrete plates. These formulae are justified by experimental data obtained. The divergence between these experimental values and the theoretical results obtained does not exceed 13,9%.

Keywords: Anchors, Bearing capacity, Steel-concrete plate, Ultimate load, Ultimate moment.