The aim of this work is to improve the fresh and hardened concrete properties made from recycled concrete aggregate, by using a non-traditional admixture.As the previous researches concluded, using different ratios of recycled concrete aggregate has a harmful effect on the properties of fresh and hardened concrete. Otherwise, itpresents a cheap, environmental and sustainable concrete by using the waste materials of demolitions to replace the natural aggregate in concrete mixes. Therefore, organic non-traditional admixture is used in this study to improve fresh and hardened concrete properties.The admixture was prepared using a cheap local material mainly from wastes of vegetable oil industries.Six different types of admixtures were prepared to select the best and most homogenous one.The suggested admixture gives best workability and increase thecompressive strengthof concrete mixescontaining recycled concrete aggregate.

The aim of this work is to improve the fresh and hardened concrete properties made from recycled concrete aggregate, by using a non-traditional admixture.As the previous researches concluded, using different ratios of recycled concrete aggregate has a harmful effect on the properties of fresh and hardened concrete. Otherwise, itpresents a cheap, environmental and sustainable concrete by using the waste materials of demolitions to replace the natural aggregate in concrete mixes. Therefore, organic non-traditional admixture is used in this study to improve fresh and hardened concrete properties.The admixture was prepared using a cheap local material mainly from wastes of vegetable oil industries.Six different types of admixtures were prepared to select the best and most homogenous one.The suggested admixture gives best workability and increase thecompressive strengthof concrete mixescontaining recycled concrete aggregate.

The important requirements for civil engineer are economic and technical in the field and this appears in fill work. The civil engineer needs a suitable soil for fill works, so the expansive soil is studied as one of the possible solution. For this research the physical, mechanical and field tests are performed. The purpose of the present paper is examining the distribution of lateral swelling pressure developed in clay soils on retaining walls after adding water and to predict the values and shape of pressures distribution for design purposes. So, five cells of strain gauges were prepared, the distance between them equals 50cm. and they were fixed at wooden sheet on bedroom's wall in one of Assiut el gadida city projects. Prediction of lateral earth pressures has been a problem to civil engineers for a long time. The first rational approach by which lateral earth pressures could be estimated was simple and practical, and they have come to be known as the classical methods of prediction of lateral earth pressure. The behaviour of soil is swelling after adding water then affects on retaining structures. The effect of soil is depending on many factors like water content, depth, the type and quantity of mineral in soil composition, the time, … etc. The results of this research give a good knowledge about the value and the distribution of lateral swelling pressure, and the results showed that the swelling pressure on retaining structure increases by increasing the water content and montmorillonite minerals content in soil. Then, the results enable the civil engineers to attain safe and suitable design for retaining structure without engineering problems...

The important requirements for civil engineer are economic and technical in the field and this appears in fill work. The civil engineer needs a suitable soil for fill works, so the expansive soil is studied as one of the possible solution. For this research the physical, mechanical and field tests are performed. The purpose of the present paper is examining the distribution of lateral swelling pressure developed in clay soils on retaining walls after adding water and to predict the values and shape of pressures distribution for design purposes. So, five cells of strain gauges were prepared, the distance between them equals 50cm. and they were fixed at wooden sheet on bedroom's wall in one of Assiut el gadida city projects. Prediction of lateral earth pressures has been a problem to civil engineers for a long time. The first rational approach by which lateral earth pressures could be estimated was simple and practical, and they have come to be known as the classical methods of prediction of lateral earth pressure. The behaviour of soil is swelling after adding water then affects on retaining structures. The effect of soil is depending on many factors like water content, depth, the type and quantity of mineral in soil composition, the time, … etc. The results of this research give a good knowledge about the value and the distribution of lateral swelling pressure, and the results showed that the swelling pressure on retaining structure increases by increasing the water content and montmorillonite minerals content in soil. Then, the results enable the civil engineers to attain safe and suitable design for retaining structure without engineering problems...

In Egypt, large quantities of coarse solid wastes are generated during the processing of phosphate ores and quarrying operations of marble and granite rocks. These solid wastes are stored in piles around or near mine sites, which cause many environmental problems. Various solutions have been sought for this major environmental problem and the best solution found is recycling. However these wastes, because of their similarity to the natural aggregate, represent a potentially useful source of material for a variety of applications. The main purpose of this research is to investigate the possibility of utilizing over screen reject generated during phosphate ore processing and rock fragments of quarrying marble and granite rocks in concrete production as full replacement of natural gravel in concrete mix. A number of tests were carried out on these wastes to determine there physical, mechanical and chemical properties, according to the ECP 203 of natural aggregate. So, concrete mixes using the above mentioned wastes as coarse aggregate were done, and then tests for fresh and hardened concrete were carried out. The mean value of uniaxial compressive strength of standard concrete cubes after 28 days of curing was found to be in order of 193 Kg/cm2 for phosphate waste, 262 kg/cm2 for marble waste, and 272 kg/cm2 for granite waste, which approach the conventional concrete used in building. The obtained results proved that these kinds of wastes can be used for concrete mix in civil construction. Admixtures may be used to improve the strength of the first one. The positive uses of these wastes are considered beneficial from the economic and environmental points of view.

In Egypt, large quantities of coarse solid wastes are generated during the processing of phosphate ores and quarrying operations of marble and granite rocks. These solid wastes are stored in piles around or near mine sites, which cause many environmental problems. Various solutions have been sought for this major environmental problem and the best solution found is recycling. However these wastes, because of their similarity to the natural aggregate, represent a potentially useful source of material for a variety of applications. The main purpose of this research is to investigate the possibility of utilizing over screen reject generated during phosphate ore processing and rock fragments of quarrying marble and granite rocks in concrete production as full replacement of natural gravel in concrete mix. A number of tests were carried out on these wastes to determine there physical, mechanical and chemical properties, according to the ECP 203 of natural aggregate. So, concrete mixes using the above mentioned wastes as coarse aggregate were done, and then tests for fresh and hardened concrete were carried out. The mean value of uniaxial compressive strength of standard concrete cubes after 28 days of curing was found to be in order of 193 Kg/cm2 for phosphate waste, 262 kg/cm2 for marble waste, and 272 kg/cm2 for granite waste, which approach the conventional concrete used in building. The obtained results proved that these kinds of wastes can be used for concrete mix in civil construction. Admixtures may be used to improve the strength of the first one. The positive uses of these wastes are considered beneficial from the economic and environmental points of view.

Using of false ceilings (FC) for decoration and covering different ducts in modern buildings is spreading so much nowadays. This paper tries to find a new employment and other benefits for using false ceilings (FC).A one dimensional transient mathematical model has been established to study the effects of using false ceiling on reduction of heat gained from concrete roof of controlled temperature space. The effect of using false ceiling (FC), with and without adding reflector sheet on its upper side facing to concrete roof on the room cooling load is studied by modeling and solving the transient heat transfer processes in the different components of the space. The results showed that using of false ceiling only without reflector sheet reduces heatgain introduced to space through 24 hours by 66.8%, while using of false ceiling with reflector sheet increases the reduction percent of heat gained from concrete roof to be 81.6% for the same period.

This paper attempts to investigate the horizontal conductor lightning striking distance estimation. An electromagnetic model was proposed to model a vertical downward lightning leader and an infinite grounded horizontal conductor by using the charge simulation method (CSM) to calculate the lateral striking distance. A formula between the lateral striking distance, the lightning current, and the horizontal conductor height was estimated. The proposed formula was compared with electromagnetic model and previous formulas. By the use of a similar methodology, a horizontal conductor voltage coefficient had been proposed and estimated. The proposed voltage coefficient was used to modify the electrogeometric model in order to study lightning striking rates of an unshielded horizontal conductor for different heights at either AC or DC voltages.

Cyclostationary feature detection is one of the most powerful spectrum sensing techniques used for cognitive radio (CR) systems. This is because of its robustness against noise uncertainties. However, this technique needs high sampling rates, which is limited by the state-of the-art analog to digital converters (ADCs), especially in wideband regime. Comressive sensing (CS) was used by many researchers for solving this problem via sub-Nyquist sampling rates. However CS solves the high sampling rate problem, but it does not reduce complexity considerably. This is because spectrum sensing is performed in three steps: sensing compressed measurements, then reconstructing the Nyquist rate signal, and finally performing cyclostationary detection (CD) on the reconstructed signal. In this paper we suggest performing CD directly on the compressed measurements skipping the reconstruction step which is the most complex step in CS. This can be realized by designing the sensing matrix with constraints different from those used in the conventional CS. Results show that performance is improved relative to applying CD on the Nyquist rate signal. This is in addition to reduction in receiver complexity resulting from reducing sampling rates. A detection probability of 78.7% can be achieved with only 7% of samples used by the conventional cyclostationary detection technique that achieves a detection probability of 32.7%.

Cyclostationary feature detection is one of the most powerful spectrum sensing techniques used for cognitive radio (CR) systems. This is because of its robustness against noise uncertainties. However, this technique needs high sampling rates, which is limited by the state-of the-art analog to digital converters (ADCs), especially in wideband regime. Comressive sensing (CS) was used by many researchers for solving this problem via sub-Nyquist sampling rates. However CS solves the high sampling rate problem, but it does not reduce complexity considerably. This is because spectrum sensing is performed in three steps: sensing compressed measurements, then reconstructing the Nyquist rate signal, and finally performing cyclostationary detection (CD) on the reconstructed signal. In this paper we suggest performing CD directly on the compressed measurements skipping the reconstruction step which is the most complex step in CS. This can be realized by designing the sensing matrix with constraints different from those used in the conventional CS. Results show that performance is improved relative to applying CD on the Nyquist rate signal. This is in addition to reduction in receiver complexity resulting from reducing sampling rates. A detection probability of 78.7% can be achieved with only 7% of samples used by the conventional cyclostationary detection technique that achieves a detection probability of 32.7%.