18 research outputs found
Dosage Limit Determination of Superplasticizing Admixture and Effect Evaluation on Properties of Concrete
No full textt— Superplasticizers are commonly known as High Range Water Reducers because it permits low water cement ratio as well asthe workability also affected. In very recent decades, superplasticizers creates milestone in the advancement of chemical admixtures for Portland cement concrete. The dramatic effect of superplasticizer (SP) on properties of fresh and hardened concrete has studied and the properties of concrete inspected are compressive strength and slump test. To determine the optimum dosage for the admixture, an experimental investigation conducted and the effect of over dosage of the SP admixture experimented, together with one control mixed.The viscosity of grout and hence the workability of concrete influenced by the dosage of superplasticizer. From dosages of admixture, the difference between concrete mixes comes, which used at amounts 400 ml/100 kg, 600 ml/100 kg, 800 ml/100 kg, 1000 ml/100 kg and 1200 ml/100 kg of cement were prepared. By dosage 1.0% of SP, compressive strength is improved and after 28 days curing it is 57 N/mm2, which is higher than that of control specimen. This paper shows that, the optimum amount of admixture must be 1.0 %. Over dosage of SP found to deteriorate the properties of concrete with indication of lower compressive strength.<br/
Stochastic Assessment of Unreinforced Masonry Veneer Wall Systems Subjected to Lateral Out-of-Plane Loading
No full textThe research reported in this thesis focused on the experimental and numerical stochastic assessment of unreinforced masonry (URM) veneer wall systems (that is, timber as a flexible backup system is connected to masonry wall via metal ties), representative of those used in the contemporary constructions in Australia, under out-of-plane loading. Previous investigations have identified a need to develop an improved understanding from the detailed examination, by test and analysis, of the behaviour of wall ties and interaction between single masonry leaf and supporting frame. Although consideration of spatial and temporal variability of the material properties for a single leaf of masonry wall has been directed at developing predictive strength models for masonry, no studies have so far been carried out towards the consideration of spatial variability of all components (mortar joints, wall ties and timber studs) of the URM veneer wall system, model error and their effect on wall system strength. This PhD thesis estimates the veneer wall system's failure load from the Monte-Carlo experimental and numerical technique. In doing so, it is hoped that the stochastic finite element models developed in this study will be used to calculate the structural reliability and fragility of masonry wall systems for new and existing construction during a structure's service life. Probabilistic veneer wall tie characterisation is accomplished to generate a nonlinear tie constitutive law for the representation of the tie behaviours in the nonlinear FEA models. A total of 50 brick-tie-timber subassemblies were tested under compression and tension, and elastic stiffness, peak strength and displacement capacity were recorded for each subassembly. The best-fitted distribution, mean and COV for each point (which define the tie constitutive law) was calculated, and correlations between these points were established. Monte-Carlo experimental investigations of 18 full-scale URM veneer wall systems with theoretically identical geometries and properties under out-of-plane loading was conducted. Ten wall systems were tested under inward loading (ties are in compression), and the remaining eight were tested under outward loading (ties are in tension). For inward loading, the airbag was pushed against the veneer wall directly, while for the outward loading, polystyrene blocks were utilised to transmit the pressure from the airbag to the veneer wall. For each loading type, one specimen was tested for semi-cyclic loading to check whether the monotonic loading can capture the overall behaviour of the cyclic response. For each batch of mortar mixed, bond wrench testing was conducted at the same age as the test for the associated wall constructed using that mix. Batch to batch variabilities were statistically analysed, and probability distributions for flexural tensile strength were established. A lognormal distribution with an aggregated mean of 0.40 MPa and 0.42 MPa for inward and outward loading, respectively, was estimated for flexural tensile strengths. From the wall tests, veneer wall system behaviour was observed and measured until the collapse or 20% post-peak drop of the peak load. Tie force history along with the timber stud deflections were also recorded and analysed to understand the veneer system failure mechanism. Parallel to the wall tests, material characterisation tests for masonry were conducted to develop the material model to define the masonry in the nonlinear FEA model. After the wall tests, all timber studs used to build the veneer wall were tested to evaluate the modulus of elasticity and bending strength. Prior to stochastic finite element analysis, a deterministic model was developed using Diana FEA 10.3 which considers the mean values for masonry, tie and timber material properties obtained from the laboratory material characterisation tests. The boundary conditions and loading arrangements were established in such a way so that it can replicate the laboratory full-scale veneer wall system tests. As expected, deterministic FEA failed to estimate the wall strength (system peak load) for inward and outward loading. A deterministic FEA with characteristic strength values for all veneer wall components was also evaluated to replicate the design (weaker than average materials) behaviour. Sensitivity analysis (one and two standard deviations below and above the mean) for deterministic FEA was conducted for target input variables, the flexural tensile strength of masonry, tie capacity (stiffness and strength), and timber stiffness to understand how these parameters affect the system peak load. The system peak load is comparatively more sensitive to the masonry bond strength and tie stiffness/strength. Moreover, if the veneer cracks earlier (lower masonry strength) and redistributes the forces in those mid-range ties before the top row of ties failed, the veneer system has the potential to resist a higher magnitude peak pressure. Spatial stochastic finite element analysis considered the spatial variability (unit to unit correlation ρ=0 and 0.4) of the wall components (mortar flexural tensile strength) and compared them with non-spatial analysis. The non-spatial analysis underestimates the wall system failure compared to spatial analysis, and the spatial analysis is considered to more realistically represent the variabilities of the URM veneer wall system. Stochastic sensitivity analysis is conducted in turn to check the sensitivity of the veneer system behaviour to variability in the various input parameters, considering one parameter at a time. Moreover, all the variabilities and uncertainties observed in the laboratory wall testing are reported and quantified to make the Monte-Carlo experimental results comparable with SFEA. From the comparison, it is evident that the stochastic finite element model developed in this study can estimate the behaviour and system peak load reasonably and are considered to be from the same population as test results
Stochastic Assessment of Unreinforced Masonry Veneer Wall Systems Subjected to Lateral Out-of-Plane Loading
No full textThe research reported in this thesis focused on the experimental and numerical stochastic assessment of unreinforced masonry (URM) veneer wall systems (that is, timber as a flexible backup system is connected to masonry wall via metal ties), representative of those used in the contemporary constructions in Australia, under out-of-plane loading. Previous investigations have identified a need to develop an improved understanding from the detailed examination, by test and analysis, of the behaviour of wall ties and interaction between single masonry leaf and supporting frame. Although consideration of spatial and temporal variability of the material properties for a single leaf of masonry wall has been directed at developing predictive strength models for masonry, no studies have so far been carried out towards the consideration of spatial variability of all components (mortar joints, wall ties and timber studs) of the URM veneer wall system, model error and their effect on wall system strength. This PhD thesis estimates the veneer wall system's failure load from the Monte-Carlo experimental and numerical technique. In doing so, it is hoped that the stochastic finite element models developed in this study will be used to calculate the structural reliability and fragility of masonry wall systems for new and existing construction during a structure's service life. Probabilistic veneer wall tie characterisation is accomplished to generate a nonlinear tie constitutive law for the representation of the tie behaviours in the nonlinear FEA models. A total of 50 brick-tie-timber subassemblies were tested under compression and tension, and elastic stiffness, peak strength and displacement capacity were recorded for each subassembly. The best-fitted distribution, mean and COV for each point (which define the tie constitutive law) was calculated, and correlations between these points were established. Monte-Carlo experimental investigations of 18 full-scale URM veneer wall systems with theoretically identical geometries and properties under out-of-plane loading was conducted. Ten wall systems were tested under inward loading (ties are in compression), and the remaining eight were tested under outward loading (ties are in tension). For inward loading, the airbag was pushed against the veneer wall directly, while for the outward loading, polystyrene blocks were utilised to transmit the pressure from the airbag to the veneer wall. For each loading type, one specimen was tested for semi-cyclic loading to check whether the monotonic loading can capture the overall behaviour of the cyclic response. For each batch of mortar mixed, bond wrench testing was conducted at the same age as the test for the associated wall constructed using that mix. Batch to batch variabilities were statistically analysed, and probability distributions for flexural tensile strength were established. A lognormal distribution with an aggregated mean of 0.40 MPa and 0.42 MPa for inward and outward loading, respectively, was estimated for flexural tensile strengths. From the wall tests, veneer wall system behaviour was observed and measured until the collapse or 20% post-peak drop of the peak load. Tie force history along with the timber stud deflections were also recorded and analysed to understand the veneer system failure mechanism. Parallel to the wall tests, material characterisation tests for masonry were conducted to develop the material model to define the masonry in the nonlinear FEA model. After the wall tests, all timber studs used to build the veneer wall were tested to evaluate the modulus of elasticity and bending strength. Prior to stochastic finite element analysis, a deterministic model was developed using Diana FEA 10.3 which considers the mean values for masonry, tie and timber material properties obtained from the laboratory material characterisation tests. The boundary conditions and loading arrangements were established in such a way so that it can replicate the laboratory full-scale veneer wall system tests. As expected, deterministic FEA failed to estimate the wall strength (system peak load) for inward and outward loading. A deterministic FEA with characteristic strength values for all veneer wall components was also evaluated to replicate the design (weaker than average materials) behaviour. Sensitivity analysis (one and two standard deviations below and above the mean) for deterministic FEA was conducted for target input variables, the flexural tensile strength of masonry, tie capacity (stiffness and strength), and timber stiffness to understand how these parameters affect the system peak load. The system peak load is comparatively more sensitive to the masonry bond strength and tie stiffness/strength. Moreover, if the veneer cracks earlier (lower masonry strength) and redistributes the forces in those mid-range ties before the top row of ties failed, the veneer system has the potential to resist a higher magnitude peak pressure. Spatial stochastic finite element analysis considered the spatial variability (unit to unit correlation ρ=0 and 0.4) of the wall components (mortar flexural tensile strength) and compared them with non-spatial analysis. The non-spatial analysis underestimates the wall system failure compared to spatial analysis, and the spatial analysis is considered to more realistically represent the variabilities of the URM veneer wall system. Stochastic sensitivity analysis is conducted in turn to check the sensitivity of the veneer system behaviour to variability in the various input parameters, considering one parameter at a time. Moreover, all the variabilities and uncertainties observed in the laboratory wall testing are reported and quantified to make the Monte-Carlo experimental results comparable with SFEA. From the comparison, it is evident that the stochastic finite element model developed in this study can estimate the behaviour and system peak load reasonably and are considered to be from the same population as test results
Stochastic assessment of unreinforced masonry veneer wall systems subjected to lateral out-of-plane loading
No full textThe research reported in this thesis focused on the experimental and numerical stochastic assessment of unreinforced masonry (URM) veneer wall systems (that is, timber as a flexible backup system is connected to masonry wall via metal ties), representative of those used in the contemporary constructions in Australia, under out-of-plane loading. Previous investigations have identified a need to develop an improved understanding from the detailed examination, by test and analysis, of the behaviour of wall ties and interaction between single masonry leaf and supporting frame. Although consideration of spatial and temporal variability of the material properties for a single leaf of masonry wall has been directed at developing predictive strength models for masonry, no studies have so far been carried out towards the consideration of spatial variability of all components (mortar joints, wall ties and timber studs) of the URM veneer wall system, model error and their effect on wall system strength. This PhD thesis estimates the veneer wall system's failure load from the Monte-Carlo experimental and numerical technique. In doing so, it is hoped that the stochastic finite element models developed in this study will be used to calculate the structural reliability and fragility of masonry wall systems for new and existing construction during a structure's service life. Probabilistic veneer wall tie characterisation is accomplished to generate a nonlinear tie constitutive law for the representation of the tie behaviours in the nonlinear FEA models. A total of 50 brick-tie-timber subassemblies were tested under compression and tension, and elastic stiffness, peak strength and displacement capacity were recorded for each subassembly. The best-fitted distribution, mean and COV for each point (which define the tie constitutive law) was calculated, and correlations between these points were established. Monte-Carlo experimental investigations of 18 full-scale URM veneer wall systems with theoretically identical geometries and properties under out-of-plane loading was conducted. Ten wall systems were tested under inward loading (ties are in compression), and the remaining eight were tested under outward loading (ties are in tension). For inward loading, the airbag was pushed against the veneer wall directly, while for the outward loading, polystyrene blocks were utilised to transmit the pressure from the airbag to the veneer wall. For each loading type, one specimen was tested for semi-cyclic loading to check whether the monotonic loading can capture the overall behaviour of the cyclic response. For each batch of mortar mixed, bond wrench testing was conducted at the same age as the test for the associated wall constructed using that mix. Batch to batch variabilities were statistically analysed, and probability distributions for flexural tensile strength were established. A lognormal distribution with an aggregated mean of 0.40 MPa and 0.42 MPa for inward and outward loading, respectively, was estimated for flexural tensile strengths. From the wall tests, veneer wall system behaviour was observed and measured until the collapse or 20% post-peak drop of the peak load. Tie force history along with the timber stud deflections were also recorded and analysed to understand the veneer system failure mechanism. Parallel to the wall tests, material characterisation tests for masonry were conducted to develop the material model to define the masonry in the nonlinear FEA model. After the wall tests, all timber studs used to build the veneer wall were tested to evaluate the modulus of elasticity and bending strength. Prior to stochastic finite element analysis, a deterministic model was developed using Diana FEA 10.3 which considers the mean values for masonry, tie and timber material properties obtained from the laboratory material characterisation tests. The boundary conditions and loading arrangements were established in such a way so that it can replicate the laboratory full-scale veneer wall system tests. As expected, deterministic FEA failed to estimate the wall strength (system peak load) for inward and outward loading. A deterministic FEA with characteristic strength values for all veneer wall components was also evaluated to replicate the design (weaker than average materials) behaviour. Sensitivity analysis (one and two standard deviations below and above the mean) for deterministic FEA was conducted for target input variables, the flexural tensile strength of masonry, tie capacity (stiffness and strength), and timber stiffness to understand how these parameters affect the system peak load. The system peak load is comparatively more sensitive to the masonry bond strength and tie stiffness/strength. Moreover, if the veneer cracks earlier (lower masonry strength) and redistributes the forces in those mid-range ties before the top row of ties failed, the veneer system has the potential to resist a higher magnitude peak pressure. Spatial stochastic finite element analysis considered the spatial variability (unit to unit correlation ρ=0 and 0.4) of the wall components (mortar flexural tensile strength) and compared them with non-spatial analysis. The non-spatial analysis underestimates the wall system failure compared to spatial analysis, and the spatial analysis is considered to more realistically represent the variabilities of the URM veneer wall system. Stochastic sensitivity analysis is conducted in turn to check the sensitivity of the veneer system behaviour to variability in the various input parameters, considering one parameter at a time. Moreover, all the variabilities and uncertainties observed in the laboratory wall testing are reported and quantified to make the Monte-Carlo experimental results comparable with SFEA. From the comparison, it is evident that the stochastic finite element model developed in this study can estimate the behaviour and system peak load reasonably and are considered to be from the same population as test results
Evaluation of Stabilized Soil Blocks with the inclusion of ‘Plastic Fibre’ as Sustainable Building Material: A Complete Review
No full textNow-a-days, huge amount of waste plastics is one of the major and important environmental hazards in Solid Waste Management (SWM) sector. So an efficient and effluent use or management is necessary to recycle thesejungles of waste plastics. Through a fundamental research, use of these waste plastics in the specific form offibres in making block may prove more efficient and undoubtedly a great feedback to Solid Waste Management.The significant effects of Plastic Fibre (which is embedded from waste plastic) on stabilized mud blocks as wellas performance effect as a sustainable building material is highlighted and reviewed in this research paperthrough a systematic investigation process. By adding Portland cement, Lime and their combination was usedfor preparing stabilized soil. Plastic carry bags (locally known as plastic bazar bags), plastic juice bottles andmineral water bottles in chopped form were the major source of Plastic Fibre. These fibres were added 0.1% &0.2% by weight of soil as reinforcement. The blocks mix compositions are different in percentage of cement andpercentage of lime with different percentage (0.1% by weight of soil & 0.2% by weight of soil) of plastic fibres.The failure patterns of the blocks were analyzed along with tested for density as well as compressive strength inMPa. From investigation it was found that, strength increases about 3% to 10% for different cement and limepercentage for blocks prepared with 0.1% of plastic fibres. From failure pattern observation it was also visiblethat, uses of fibres reinforcement improve ductility which was compared with raw block
Stochastic Assessment of Unreinforced Masonry Veneer Wall Systems Subjected to Lateral Out-of-Plane Loading
No full textThe research reported in this thesis focused on the experimental and numerical stochastic assessment of unreinforced masonry (URM) veneer wall systems (that is, timber as a flexible backup system is connected to masonry wall via metal ties), representative of those used in the contemporary constructions in Australia, under out-of-plane loading. Previous investigations have identified a need to develop an improved understanding from the detailed examination, by test and analysis, of the behaviour of wall ties and interaction between single masonry leaf and supporting frame. Although consideration of spatial and temporal variability of the material properties for a single leaf of masonry wall has been directed at developing predictive strength models for masonry, no studies have so far been carried out towards the consideration of spatial variability of all components (mortar joints, wall ties and timber studs) of the URM veneer wall system, model error and their effect on wall system strength. This PhD thesis estimates the veneer wall system's failure load from the Monte-Carlo experimental and numerical technique. In doing so, it is hoped that the stochastic finite element models developed in this study will be used to calculate the structural reliability and fragility of masonry wall systems for new and existing construction during a structure's service life. Probabilistic veneer wall tie characterisation is accomplished to generate a nonlinear tie constitutive law for the representation of the tie behaviours in the nonlinear FEA models. A total of 50 brick-tie-timber subassemblies were tested under compression and tension, and elastic stiffness, peak strength and displacement capacity were recorded for each subassembly. The best-fitted distribution, mean and COV for each point (which define the tie constitutive law) was calculated, and correlations between these points were established. Monte-Carlo experimental investigations of 18 full-scale URM veneer wall systems with theoretically identical geometries and properties under out-of-plane loading was conducted. Ten wall systems were tested under inward loading (ties are in compression), and the remaining eight were tested under outward loading (ties are in tension). For inward loading, the airbag was pushed against the veneer wall directly, while for the outward loading, polystyrene blocks were utilised to transmit the pressure from the airbag to the veneer wall. For each loading type, one specimen was tested for semi-cyclic loading to check whether the monotonic loading can capture the overall behaviour of the cyclic response. For each batch of mortar mixed, bond wrench testing was conducted at the same age as the test for the associated wall constructed using that mix. Batch to batch variabilities were statistically analysed, and probability distributions for flexural tensile strength were established. A lognormal distribution with an aggregated mean of 0.40 MPa and 0.42 MPa for inward and outward loading, respectively, was estimated for flexural tensile strengths. From the wall tests, veneer wall system behaviour was observed and measured until the collapse or 20% post-peak drop of the peak load. Tie force history along with the timber stud deflections were also recorded and analysed to understand the veneer system failure mechanism. Parallel to the wall tests, material characterisation tests for masonry were conducted to develop the material model to define the masonry in the nonlinear FEA model. After the wall tests, all timber studs used to build the veneer wall were tested to evaluate the modulus of elasticity and bending strength. Prior to stochastic finite element analysis, a deterministic model was developed using Diana FEA 10.3 which considers the mean values for masonry, tie and timber material properties obtained from the laboratory material characterisation tests. The boundary conditions and loading arrangements were established in such a way so that it can replicate the laboratory full-scale veneer wall system tests. As expected, deterministic FEA failed to estimate the wall strength (system peak load) for inward and outward loading. A deterministic FEA with characteristic strength values for all veneer wall components was also evaluated to replicate the design (weaker than average materials) behaviour. Sensitivity analysis (one and two standard deviations below and above the mean) for deterministic FEA was conducted for target input variables, the flexural tensile strength of masonry, tie capacity (stiffness and strength), and timber stiffness to understand how these parameters affect the system peak load. The system peak load is comparatively more sensitive to the masonry bond strength and tie stiffness/strength. Moreover, if the veneer cracks earlier (lower masonry strength) and redistributes the forces in those mid-range ties before the top row of ties failed, the veneer system has the potential to resist a higher magnitude peak pressure. Spatial stochastic finite element analysis considered the spatial variability (unit to unit correlation ρ=0 and 0.4) of the wall components (mortar flexural tensile strength) and compared them with non-spatial analysis. The non-spatial analysis underestimates the wall system failure compared to spatial analysis, and the spatial analysis is considered to more realistically represent the variabilities of the URM veneer wall system. Stochastic sensitivity analysis is conducted in turn to check the sensitivity of the veneer system behaviour to variability in the various input parameters, considering one parameter at a time. Moreover, all the variabilities and uncertainties observed in the laboratory wall testing are reported and quantified to make the Monte-Carlo experimental results comparable with SFEA. From the comparison, it is evident that the stochastic finite element model developed in this study can estimate the behaviour and system peak load reasonably and are considered to be from the same population as test results
Magnitude and Impact Analysis of Road Traffic Noise Pollution at Port City Chittagong, Bangladesh
No full textChittagong is the biggest and only port city of Bangladesh. Though Dhaka is the capital but heavy traffic noise pollution is a common phenomenon in port city Chittagong, as it is the commercial capital of Bangladesh. This study provides road traffic noise pollution analysis of Chittagong as well its effects on inhabitants of the city. For computing the magnitude of the traffic noise this big city is divided into 11 segments according to the pressure and magnitude of vehicle based on past 10 year experience. Statistical noise index L10 (18 hour) was measured and computed at these 11 segments which consist of 12 stations. The average of two nearby stations is taken as the noise levels of particular segment. British standard of Calculation of Road Traffic Noise (CRTN) method was used to finalize the present and future noise levels at these 12 stations. CRTN method is very effective for predicting noise levels in Chittagong because the CRTN emphasizes those factors which are very much related to this city. Studies showed that Chittagong is environmentally polluted with noise continuously and the ranges of noise levels are 75.29 to 90.12 dB (A) which exceeds the maximum allowable limit of 65 dB (A). By CRTN method future noise levels also predicted and which is undoubtedly higher than the present. To evaluate the impacts on community and inhabitants, a social survey was carried and from the survey it was evident that the community, who lives in Chittagong city, is very much worried about this noise pollution as many of them live beside the main roads. Noise pollution is an important factor for transformation of city dwellers to any quieter areas
Menstrual Hygiene Condition of Adolescent Schoolgirls at Chittagong Division in Bangladesh
No full textIn developing countries like Bangladesh, menstrual hygiene and management is not prime concern in the sector of reproductive health and water, sanitation and hygiene. To achieve Millennium Development goals (MDGs) within right time a study on women reproductive health of Bangladesh is very necessary as it ensures environment sustainability, gender equality and women empowerment. A typical and systematic study on adolescentschool girls of greater Chittagong Division of Bangladesh on menstrual hygiene and management condition were carried to identify the prevailing knowledge and experiences and their implications. Chittagong division consists of 11 districts including total land area 33,771.18 Sq. Km. where the total land area of Bangladesh is 1,47,570 Sq. Km. By using mixed methods both quantitative and qualitative, data was collected from 1373 adolescent school girls from 22 schools of 11 districts. The survey includes some pre-questionnaires and focus group discussions and interviews. Knowledge and beliefs, experiences during menstruation, seclusion and absenteeism and finally hygiene practices were analysed through this descripti ve cross sectional study. Data wasn‟t fluctuated very much in different district except Khagrachhari, Rangamati and Bandarban. Maximum number of survey respondents (96%) reported that they had known about menstruation before their menarche, 90% respondents were facing abdominal pain and mental stress is another key thing due to extra thinking about her menstruation and maintain secrecy from others, 95% of them maintaining some restrictions due to religious issue and for other significant reason. Almost 39% of total respondents was being absent in school at least one day, during menstruation period and reasonbehind this circumstances were also evaluated. Re-usable cloths were preferred by the tribal girls (Khagrachhari, Rangamati and Bandarban district) whereas sanitary pad was preferable by rest of the district. In total 49% used re-usable cloths and use rate of old piece of cloth was higher at rural area. Absorbent material used, bath taken, cleaning and changing, availability of toilet, disposal of absorbent material in last menstruation were analysed toidentify their hygiene practice. Finally some recommendations are proposed after analyzing the focus group discussions and intervie
Strength Evaluation of Mortar by Inclusion of Stone Dust as a Cement and Sand Replacing Material
No full textMortar, a matrix of concrete which is a masonry product, composed of binder and fine aggregates. It is an essential associate in any reinforced structural construction. The strength of mortar is a special concern to the engineer because mortar is responsible to give protection in the outer part of the structure as well as at a brick joint in masonry wall system. The lack of mortar strength sometimes throws the whole structure in a great danger. Cement, sand and water are the key parameters of mortar which are dealing with the strength directly. The purpose of this research is to investigate the compressive and tensile strengths of mortar by replacing the cement and sand by stone dust. This research is focused on the comparison between fresh mortar and modified mortar. For sand replacement, the gradation and fineness modulus of stone dusts was kept similar to that of sand. Stone dusts passing by No. 200 sieve was used as cement replacing material. The portion of dusts which was retained on No. 100 sieve was separated to substitute sand and the remaining part of dusts was made finer by abrasion machine. Then the stone dusts were screened again by No. 200 sieve and the dusts passing by No. 200 was used as the cement. The compressive and tensile strengths of modified mortar were investigated by replacing of 20%, 30% and 40% of fine aggregates as well as replacing of 5% of cement by stone dusts. Several numbers of cube and briquette samples were cast with aforementioned proportions to investigate compressive and tensile strengths at 7 days and 28 days of curing. From tested results, it was found that the compressive strength of samples of 30% of sand replacing stone dust with 0% of cement replacing stone dust increases by 12% and 17% at 7 and 28 days while for the tensile strength it was increased by 8.7%. However, the mechanical properties of mortar with stone dusts as replacement of cement shows no satisfactory results
Menstrual Hygiene Condition of Adolescent Schoolgirls at Chittagong Division in Bangladesh
No full textIn developing countries like Bangladesh, menstrual hygiene and management is not prime concern in the sector of reproductive health and water, sanitation and hygiene. To achieve Millennium Development goals (MDGs) within right time a study on women reproductive health of Bangladesh is very necessary as it ensures environment sustainability, gender equality and women empowerment. A typical and systematic study on adolescentschool girls of greater Chittagong Division of Bangladesh on menstrual hygiene and management condition were carried to identify the prevailing knowledge and experiences and their implications. Chittagong division consists of 11 districts including total land area 33,771.18 Sq. Km. where the total land area of Bangladesh is 1,47,570 Sq. Km. By using mixed methods both quantitative and qualitative, data was collected from 1373 adolescent school girls from 22 schools of 11 districts. The survey includes some pre-questionnaires and focus group discussions and interviews. Knowledge and beliefs, experiences during menstruation, seclusion and absenteeism and finally hygiene practices were analysed through this descripti ve cross sectional study. Data wasn‟t fluctuated very much in different district except Khagrachhari, Rangamati and Bandarban. Maximum number of survey respondents (96%) reported that they had known about menstruation before their menarche, 90% respondents were facing abdominal pain and mental stress is another key thing due to extra thinking about her menstruation and maintain secrecy from others, 95% of them maintaining some restrictions due to religious issue and for other significant reason. Almost 39% of total respondents was being absent in school at least one day, during menstruation period and reasonbehind this circumstances were also evaluated. Re-usable cloths were preferred by the tribal girls (Khagrachhari, Rangamati and Bandarban district) whereas sanitary pad was preferable by rest of the district. In total 49% used re-usable cloths and use rate of old piece of cloth was higher at rural area. Absorbent material used, bath taken, cleaning and changing, availability of toilet, disposal of absorbent material in last menstruation were analysed toidentify their hygiene practice. Finally some recommendations are proposed after analyzing the focus group discussions and intervie
