This study investigated the effect of adding different
percentages of sand to several types of clay soils, Which used as
liners at solid waste landfill sites in order to find the best mixing
ratio (sand - clay).
This research aims to study the effect of adding inorganic waste (Marble powder -
glass powder) on the volumetric and longitudinal shrinkage curves at unsaturated polyester
resin, tests showed that samples exposed to volumetric and longitudinal shr
ink and
occurrence of consecutive gradients in volumetric shrinkage values. Whatever the ratio of
the added materials (marble powder - the glass powder) will effect the behaviour of the
unsaturated polyester hardening, that means it will effect the volumetric shrinkage.
It is necessary to study the volumetric and longitudinal shrinkage values because
they affect the product size to be dealt with, this value should be taken into account in the
design so that should be added this amount of volumetric shrinkage to the dimensions to
designed templates in order to avoid potential variations occurring in the final product.
Preliminary results showed that the value of volumetric shrinkage got up (5%) and the
curves tend to stability, almost three weeks after the initial hardening incident.
In this research the influence of the fineness of natural
pozzolana and lime on the properties of compaction ,
unconfined compressive strength and linear shrinkage of
clayey soil was experimented the finessess of natural pozzolana
used in this re
earch were 3500,4000,4500 cm²/g , finessess of
lime 4000 , 5000 , 6000 cm²/g.
Being critical, the stability of clayey soil, is a priority for the
civil engineer in constructions of roads and buildings. This
experimental study comes in the context of examination of the
effectiveness of menial stabilizers. Lime (L), Natural P
ozzolana
(NP), and Combinations of both, were examined to enhance the
characteristics of compaction, consistency and to restrict the
shrinkage behavior of clayey soil.
Fiber reinforced polymer (FRP) plates have gained popularity in the strengthening of reinforced concrete (RC) members due to the high strength to weight ratio, the ease of installation and low maintenance costs compared to other systems such as steel
plates. Also, external bonding of fiber reinforced polymer (FRP) plate has been proven to be an effective method to strengthen and damage RC structures. However, not much attention has been given to the long-term behavioral aspects of FRP-strengthened RC members. It is difficult to accurately predict the long-term deflection, crack width and behavior of FRP-strengthened RC members.
This study presents a method for predicting the deflections at any time of the service life of normal and high strength concrete structures, loaded at any age, creep coefficient and shrinkage strain and the participation of the compressive steel for RC beams, and for RC beams strengthened with FRP plates.
The accurate prediction of deflections is a complex problem which requires the use of non-linear and time-dependent analytical methods. These methods are, in general, time consuming and require great effort[6-13]. However, at the design stage, simple but reliable methods which take into account the most important parameters influencing the long-term deflections may be very useful to adequately design the structure. For that purpose, many simplified methods have been developed [1-2-3-4-14]. Equations have been programmed to access the method combines the simplicity and accuracy and provides valuable information about the influence of each parameter on the increasing deflections with time.
The analytical values are compared to the experimental results from some existing papers [8-9], and to the results obtained from ACI code [1]. It is found that the analytical method is in a good agreement with the experimental results from some existing papers
[8-9].
Cracks are considered important defects in concrete elements, it was noticed after constructing the reinforced concrete walls related to the Foundation, that after a short time after the hardening of concrete and without any overloading on the wall,
there have been vertical cracks of regular distances along each wall we noticed this phenomenon it had happened in many construction projects. We have described the situation, we have also explained, analyzed it by examining its reasons. By a thorough study of three projects carried out in lattakia including scale decanter, building of a tourist hotel and a trade centre, which crack width ranging from 1.25 mm to 3 mm, the height differed in each case studied. Ultimately we have found the practical solutions to avoid this phenomenon including adoption of longitudinal joints for reinforced concrete walls, spacing is about thirty times the wall thickness in order to avoid cracks caused by shrinkage and thermal stress where the depth of joint about 20 mm and the width ranging between 15 mm to 20 mm implemented on both sides of the wall internal and external. After hardening of concrete and lifting the wooden template fill the joints with filler flexible materials.
Background& Objective: Acrylic resin, poly-methacrylate provisional materials, have been no longer used
because of low strength, poor marginal fit, low resistance, and color stability. New resin systems, such as
higher (meth) acrylates, and di-meth
acrylate were developed to improve the mechanical and physical
properties.
Investigate polymerization shrinkage-strain, and Exo-thermic peak-temperatures of three new provisional
materials based on di-methacrylate, and one of mono-methacrylate.
