Hydroxamated polyacrylamide（HPAM） was synthesized from polyacrylamide（PAM） with high relative molecular mass under the optimum reaction conditions（p H 12 and a molar ratio of hydroxylamine to amide groups of 1.5 ...Hydroxamated polyacrylamide（HPAM） was synthesized from polyacrylamide（PAM） with high relative molecular mass under the optimum reaction conditions（p H 12 and a molar ratio of hydroxylamine to amide groups of 1.5 at 50 ℃for 12 h）. The hydroxamate groups of HPAM were verified by Fourier transform infrared spectrum（FT-IR）. 46%（molar fration） hydroxamate groups and 23%（molar fraction） carbonyl groups on HPAM were determined by conductometric titration combined with Kjeldahl＇s microanalysis method. The settling performance achieved at different flocculant dosages was investigated with high goethite-containing red mud slurry of simulated Bayer process synthesized in laboratory. It turns out that the settling performance of high goethite-containing red mud was better with HPAM. The average settling rate of red mud in the first 5 min and the turbidity of supernatant after settling for 30 min are 2.36 m/h and 507 NTU, respectively, at a flocculant dosage of 120 g/t, which is similar to that achieved with Hx-600.展开更多
Cement improves properties of soil materials, such as durability, stiffness, strength and moisture susceptibility. Each of them needs different cement contents that might not be suitable for other properties. Typicall...Cement improves properties of soil materials, such as durability, stiffness, strength and moisture susceptibility. Each of them needs different cement contents that might not be suitable for other properties. Typically, high cement content is desirable for durability, but not for shrinkage and cracking issues on the surface. Thus, improving durability with low cement content while complying with other requirements is an ideal aim, which may be achieved by pozzolanic supplementary products. Pozzolans contribute in hydration reactions and optimise cement consumptions in favour of durable and low shrinkage products. In this paper, the mixes of nano-silica and fly ash are considered to investigate their effect on strength, durability and shrinkage of modified CRB （crushed rock base） material. In the end, the benefits and features of nano-silica as a pozzolanic material will be focused and discussed more for effective cement consumption in soils.展开更多
Industrialization has though brought comfort to our daily lives,but it has placed a lot of pressure on the planet’s natural resources,subsequently,it has adversely affected the environment.As the need for cement in t...Industrialization has though brought comfort to our daily lives,but it has placed a lot of pressure on the planet’s natural resources,subsequently,it has adversely affected the environment.As the need for cement in the construction sector has grown,it has climbed dramatically globally.Around the world,more than 10 billion cubic meters of concrete are produced each year;it is doubtful that this volume will decrease.A significant expected rise in CO_(2) emissions is caused by increased cement demand.According to the UN Environment Program,buildings are responsible for up to 41%of global anthropogenic carbon emissions.The primary source of greenhouse gases utilized in the manufacturing of cement is clinker.Due to the unsustainable supply of fly ash,calcined clay appears to be a better Supplemental Cementitious Material(SCMs).Kaolin clay is widely available in Pakistan.The purpose of this investigation is to describe the mineral and thermal characteristics of Pakistani clays by examining their geographic distribution.Clay samples were gathered from 39 different places throughout Pakistan during a field investigation program.X-ray diffraction,X-ray Fluorescence,Reactivity,and thermogravimetric analyses were used to analyze the clay samples’mineral content and thermal characteristics.This study demonstrates that Pakistan has a substantial amount of kaolin clay reserves close to existing groups of cement plants.Pakistani clays can be utilized as SCM in the production of limestone calcined clay cement(LC^(3))due to the country’s vast kaolin clay reserves.This study further supports the viability of producing LC^(3) in the nation by providing a thorough analysis of the cement business,known deposits of qualifying clay,and the country’s cement production process.展开更多
In the present paper, two models based on artificial neural networks and genetic programming for predicting split tensile strength and percentage of water absorption of concretes containing Cr2O3 nanoparticles have be...In the present paper, two models based on artificial neural networks and genetic programming for predicting split tensile strength and percentage of water absorption of concretes containing Cr2O3 nanoparticles have been developed at different ages of curing. For purpose of building these models, training and testing using experimental results for 144 specimens produced with 16 different mixture proportions were conducted. The data used in the multilayer feed forward neural networks models and input variables of genetic programming models are arranged in a format of 8 input parameters that cover the cement content, nanoparticle content, aggregate type, water content, the amount of superplasticizer, the type of curing medium, age of curing and number of testing try. According to these input parameters, in the neural networks and genetic programming models the split tensile strength and percentage of water absorption values of concretes containing Cr2O3 nanoparticles were predicted. The training and testing results in the neural network and genetic programming models have shown that every two models have strong potential for predicting the split tensile strength and percentage of water absorption values of concretes containing Cr2O3 nanoparticles. It has been found that NN and GEP models will be valid within the ranges of variables. In neural networks model, as the training and testing ended when minimum error norm of network was gained, the best results were obtained and in genetic programming model, when 4 genes were selected to construct the model, the best results were acquired. Although neural network has predicted better results, genetic programming is able to predict reasonable values with a simpler method rather than neural network.展开更多
基金Project(51174231)supported by the National Natural Science Foundation of China
文摘Hydroxamated polyacrylamide（HPAM） was synthesized from polyacrylamide（PAM） with high relative molecular mass under the optimum reaction conditions（p H 12 and a molar ratio of hydroxylamine to amide groups of 1.5 at 50 ℃for 12 h）. The hydroxamate groups of HPAM were verified by Fourier transform infrared spectrum（FT-IR）. 46%（molar fration） hydroxamate groups and 23%（molar fraction） carbonyl groups on HPAM were determined by conductometric titration combined with Kjeldahl＇s microanalysis method. The settling performance achieved at different flocculant dosages was investigated with high goethite-containing red mud slurry of simulated Bayer process synthesized in laboratory. It turns out that the settling performance of high goethite-containing red mud was better with HPAM. The average settling rate of red mud in the first 5 min and the turbidity of supernatant after settling for 30 min are 2.36 m/h and 507 NTU, respectively, at a flocculant dosage of 120 g/t, which is similar to that achieved with Hx-600.
文摘Cement improves properties of soil materials, such as durability, stiffness, strength and moisture susceptibility. Each of them needs different cement contents that might not be suitable for other properties. Typically, high cement content is desirable for durability, but not for shrinkage and cracking issues on the surface. Thus, improving durability with low cement content while complying with other requirements is an ideal aim, which may be achieved by pozzolanic supplementary products. Pozzolans contribute in hydration reactions and optimise cement consumptions in favour of durable and low shrinkage products. In this paper, the mixes of nano-silica and fly ash are considered to investigate their effect on strength, durability and shrinkage of modified CRB （crushed rock base） material. In the end, the benefits and features of nano-silica as a pozzolanic material will be focused and discussed more for effective cement consumption in soils.
基金support from China National Key R&D Program‐International Scientific and Technological Innovation Cooperation Key Project(Grant No.:2018YFE0106300)The research was mainly supported by the Higher Education Commission of Pakistan(National Research Program for Universities—NRPU Project No.14074).
文摘Industrialization has though brought comfort to our daily lives,but it has placed a lot of pressure on the planet’s natural resources,subsequently,it has adversely affected the environment.As the need for cement in the construction sector has grown,it has climbed dramatically globally.Around the world,more than 10 billion cubic meters of concrete are produced each year;it is doubtful that this volume will decrease.A significant expected rise in CO_(2) emissions is caused by increased cement demand.According to the UN Environment Program,buildings are responsible for up to 41%of global anthropogenic carbon emissions.The primary source of greenhouse gases utilized in the manufacturing of cement is clinker.Due to the unsustainable supply of fly ash,calcined clay appears to be a better Supplemental Cementitious Material(SCMs).Kaolin clay is widely available in Pakistan.The purpose of this investigation is to describe the mineral and thermal characteristics of Pakistani clays by examining their geographic distribution.Clay samples were gathered from 39 different places throughout Pakistan during a field investigation program.X-ray diffraction,X-ray Fluorescence,Reactivity,and thermogravimetric analyses were used to analyze the clay samples’mineral content and thermal characteristics.This study demonstrates that Pakistan has a substantial amount of kaolin clay reserves close to existing groups of cement plants.Pakistani clays can be utilized as SCM in the production of limestone calcined clay cement(LC^(3))due to the country’s vast kaolin clay reserves.This study further supports the viability of producing LC^(3) in the nation by providing a thorough analysis of the cement business,known deposits of qualifying clay,and the country’s cement production process.
文摘In the present paper, two models based on artificial neural networks and genetic programming for predicting split tensile strength and percentage of water absorption of concretes containing Cr2O3 nanoparticles have been developed at different ages of curing. For purpose of building these models, training and testing using experimental results for 144 specimens produced with 16 different mixture proportions were conducted. The data used in the multilayer feed forward neural networks models and input variables of genetic programming models are arranged in a format of 8 input parameters that cover the cement content, nanoparticle content, aggregate type, water content, the amount of superplasticizer, the type of curing medium, age of curing and number of testing try. According to these input parameters, in the neural networks and genetic programming models the split tensile strength and percentage of water absorption values of concretes containing Cr2O3 nanoparticles were predicted. The training and testing results in the neural network and genetic programming models have shown that every two models have strong potential for predicting the split tensile strength and percentage of water absorption values of concretes containing Cr2O3 nanoparticles. It has been found that NN and GEP models will be valid within the ranges of variables. In neural networks model, as the training and testing ended when minimum error norm of network was gained, the best results were obtained and in genetic programming model, when 4 genes were selected to construct the model, the best results were acquired. Although neural network has predicted better results, genetic programming is able to predict reasonable values with a simpler method rather than neural network.
