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Resistance to acid degradation,sorptivity,and setting time of geopolymer mortars

Frontiers of Structural and Civil Engineering 2022年第6期16卷 781-791页

作者： Osama A MOHAMED Rania AL-KHATTAB Waddah AL-HAWAT College of Engineering Abu Dhabi UniversityAbu DhabiUnited Arab Emirates

Experimental evaluations were conducted to determine the water sorptivity,setting time,and resistance to a highly acidic environment,of mortar with alkali-activated ground granulated blast furnace slag(GBS)binder and also of combinations of fly ash and GBS *** were activated using mixtures of NaOH and Na_(2)SiO_(3)*** molarity of NaOH in the mixtures ranged from 10 mol·L^(−1)to 16 mol·L^(−1),and the Na_(2)SiO_(3)/NaOH ratio was varied from 1.5 to *** samples were produced using three binder combinations:1)GBS as the only binder;2)blended binder with a slag-to-fly ash ratio of 3:1;and 3)mixed binder with 1:1 ratio of slag to fly *** samples were mixed and cured at(22±2)°C till the day of the *** impact of activator solution alkalinity,activator ratio Na_(2)SiO_(3)/NaOH,GBS content on the rate of water absorption were *** 7,28,and 90 d of immersion in a 10%sulfuric acid solution,the resistance of a geopolymer matrix to degradation was assessed by measuring the change in sample *** influence of solution alkalinity and relative fly ash content on setting times was ***-activated mortar with a slag-to-fly ash ratio of 3:1 had the least sorptivity compared to the two other binder combinations,at each curing age,and for mortars made with each of the NaOH alkaline activator *** sorptivity decreased with age and sodium hydroxide concentrations,suggesting the production of geopolymerization *** reduction in weight of sample occurred after immersion in the strong acid H_(2)SO_(4)solution for three months,regardless of binder *** was due to the synthesis of hydration and geopolymerization products in the presence of curing water,which outweighed the degradation of the geopolymer matrix caused by sulfuric acid.

关键词： alkali-activated materials fly ash sorptivity durability of concrete sodium hydroxide sodium silicates reduction in CO_(2)emissions sulfuric acid

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An Analytical Method for Relationship Between Hydraulic Diffusivity and Soil sorptivity

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Pedosphere 2006年第4期16卷 444-450页

作者： WANG Quan-Jiu ZHANG Jiang-Hui FAN Jun State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau Institute of Soil and Water Conservation Chinese Academy of Sciences Yangling 712100 （China） Institute of Water Resources Research Xi＇an University of Technology Xi＇an 710048 （China） Northwest A ＆ F University Yangling 712100 （China）

A simple method was developed to relate soil sorptivity to hydraulic diffusivity and water absorption experiments were conducted utilizing one-dimensional horizontal soil columns to validate the relationship. In addition, an estimation method for hydraulic diffusivity with disc infiltrometer was developed. The results indicated a favorable fit of the theoretical relation to the experimental data. Also, the experiment with disc infiltrometer for estimating the diffusivity showed that the new method was feasible.

关键词： disc infiltrometer hydraulic diffusivity infiltration soil hydraulic parameter sorptivity

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sorptivity and rapid chloride ion penetration of self-compacting concrete using fly ash and copper slag

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AI in Civil Engineering 2023年第1期2卷 63-76页

作者： Sambangi Arunchaitanya Subhashish Dey Civil Engineering Department Gudlavaleru Engineering CollegeGudlavalleruAndhra PradeshIndia

This paper represents experimental work on the mechanical and durability parameters of self-compacting concrete(SCC)with copper slag(CS)and fly ash(FA).In the first phase of the experiment,certain SCC mixes are prepared with six percentages of FA replacing the cement ranging from 5%to 30%.In the second phase,copper slag replaces fine aggregate at an interval of 20%to 100%by taking the optimum percentage value of *** performance of SCC mixes containing FA and copper slag is measured with fresh properties,compressive,split tensile and flexural *** durability metrics,such as resistance against chloride and voids in the concrete matrix,is measured with rapid chloride ion penetration test(RCPT)and sorptivity *** microstructure of the SCC is analyzed by using SEM and various phases available in the concrete matrix identified with XRD *** is found that when replacing cement with 20%of FA and replacing fine aggregate with 40%of copper slag in SCC,higher mechanical strengths will be *** of chloride and voids in the concrete matrix reaches the optimum value at 40%;and with the increase of dosage,the quality of SCC will be ***,it is recommended that copper slag be used as a sustainable material for replacement of fine aggregate.

关键词： Copper slag RCPT sorptivity Self compacting concrete

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Analytical Methods for Prediction of Water Absorption in Cement-Based Material

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China Ocean Engineering 2009年第4期23卷 719-728页

作者：王立成 State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology

The capillary absorption of water by unsaturated cement-based material is the main reason of degradation of the structures subjected to an aggressive environment since water often acts as the transporting medium for damaging contaminants. It is well known that the capillarity coefficient and sorptivity are two important parameters to characterize the water absorption of porous materials. Generally, the former is used to describe the penetration depth or height of water transport, which must be measured by special and advanced equipment. In contrast, the sorptivity represents the relationship between cumulative volume of water uptake and the squareroot of the elapsed time, which can be easily measured by the gravimetric method in a normal laboratory condition. In the present study, an analytical method is developed to build up a bridge between these two parameters, with the purpose that the sorptivity or the gravimetric method can be used to predict the penetration depth of water absorption. Additionally, a new model to explain the dependence of sorptivity on initial water content of the material is developed in order to fit the in situ condition. The comparison of predicted results by the analytical method with experimental data or numerical calculation results, as well as some previous models, validates the feasibility of the methods presented in this paper.

关键词： water, absorption capillarity coefficient sorptivity cement-based material initial water content

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Investigation of cement mortar incorporating Bacillus sphaericus

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International Journal of Smart and Nano Materials 2016年第2期7卷 91-105页

作者： Kirti Kanta Sahoo Aparna K.Sathyan Chandni Kumari Pradip Sarkar Robin Davis Department of Civil Engineering National Institute of Technology RourkelaOdishaIndia

Ureolytic-type bacteria has been used to improve the strength of cement mortar by the precipitation of calcium *** the present study Bacillus sphaericus has been used to improve the properties of cement mortar such as setting time,compressive strength and *** setting time is found to be unaffected by the presence of *** is found that compressive strength at both 7-days and 28-days of mortar cube increases with the increase of bacteria *** the optimum bacteria dosage of 107 cells/ml,the average compressive strength increases by 58%(at 7 day)and 23%(at 28 day)over the control *** sorpitivity coefficient decreases as the concentration of bac-terial cells *** mineralogy and morphology of the cal-cium carbonate precipitation have been tested by XRD and FESEM.

关键词： bacteria setting time compressive strength calcite precipitation sorptivity

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Estimation of Infiltration Models’ Parameters Using Regression Analysis in Irrigation Fields of Northern Ghana

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Open Journal of Soil Science 2021年第3期11卷 164-176页

作者： Abdallah Salifu Felix. K. Abagale Gordana Kranjac-Berisavljevic Department of Agricultural Mechanisation and Irrigation Technology Faculty of Agriculture Food and Consumer Sciences University for Development Studies Tamale Ghana West African Centre for Water Irrigation and Sustainable Agriculture University for Development Studies Tamale Ghana

The quantification of soil infiltration is necessary for the estimation of water accessibility in soils for plant growth and development. Field infiltration tests runs were conducted on agricultural soils in three irrigation sites of Northern Ghana. The field data were fitted into Green and Ampt, Kostiakov, Philip, Holtan, Soil Conservation Service and Horton infiltration models for the determination of the unknown model parameters. Regression analysis at 95% confidence level using GraphPad Prism 8. Laboratory and field data on infiltration were used for the model fitting and the unknown parameters were determined using the calibrated models. The k and n parameters of Kostiakov model at Bontanga study site were found to be k = 28.0027 and n = 0.5902, k = 17.0294 and n = 0.4504 for Golinga and k = 23.0356 and n = 0.6339 for Libga. For all the models, the coefficient of determination ranged from 0.7612 to 0.9876 indicating strong relationships. Only Holtan model gave different values at all the three study sites. The parameter GIa and ic of the Holtan model drawn from hydrologic soil group were the same at all the study sites because of the same vegetative cover and surface conditions. The study observed the values of the parameters to have influenced the models’ performance.

关键词： Parameter Infiltration Model Regression sorptivity Transmissivity

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Effectiveness of Rice Husk and Sugarcane Bagasse Ashes Blended Cement in Improving Properties of Concrete

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Journal of Modern Physics 2023年第8期14卷 1-19页

作者： Johnson Adegaye Adebola Catherine Mayowa Ikumapayi Chinwuba Arum Civil Engineering Department Federal University of Technology Akure Nigeria

This paper emphasized the use of rice husk ash (RHA) and sugarcane bagasse ash (SBA) in improving concrete properties, and also their combined effects on workability, compressive strength, flexural strength, permeability and water absorption capacity. Thus, in this study, the water-to-cement ratio was kept constant (0.45), the binder materials content for conventional mix was kept constant at (350 kg/m3) and the partial replacement of cement with RHASBA used was 5%, 10%, 15%, 20%, 25%, and 30% by weight of cement. The maximum compressive strength was noted at a 5% replacement level of cement with RHASBA. The Results showed that the optimum replacement of cement with RHASBA in concrete was 5%, which was found to increase the compressive strength by 15%, flexural strength by 3.4%, lowered permeability by 50%, lowered sorptivity by 11.34% as compared with control concrete at 90 days of curing time. The micro-structural test results further established that RHA and SBA have a high content of SiO2 which enables them to be more reactive in concrete and also revealed that the presence of RHASBA depletes Ca(OH)2 crystals, converting it into CaH2O4Si (C-S-H gel) leading to the strengthening of bond within the concrete matrix.

关键词： Concrete Rice Husk Ash Sugarcane Bagasse Ash Compressive Strength Permeability sorptivity

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Estimation of Soil Hydrodynamic Parameters Related to Agricultural Practices -Case of the Tougou Experimental Site （Burkina Faso）

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Journal of Environmental Science and Engineering(A) 2017年第10期6卷 527-534页

作者： Dial Niang Mahamadou Koita Amadou Keita Medogbe Christelle Manuela Houndayi Cheick Oumar Zoure Amagana Emmanuel Dara Department of Civil Engineering and Hydraulics. the International Institute for Water and Environmental Engineering Laboratory of Hydrolog v and Water ResourcesRue de la Science-BP 594 Ouagadougou 01 Burkina Faso

This study aims to estimate the hydrodynamic properties of soils under various agricultural practices in the Tougou catchment in northern Burkina Faso. The methodology adopted is based on the determination of the unsaturated hydraulic conductivity and capillary sorptivity close to saturation. This method relies on the measurement of the transient infiltration flux at the soil surface with imposed hydraulic head varying from -60 to -20 mm. These tests are carried out on control, stony line, half-moon and zai plots. The results show a difference in hydrodynamic parameters according to the agricultural practices. The unsaturated hydraulic conductivity is 33.1 cm/h, 13.1 cm/h, 20.3 cm/h and 4.0 cm/h for zai, control, stony line and half-moon plots respectively. The unsaturated hydraulic conductivity is 33.1 cm/h, 13.1 cm/h, 20.3 cm/h and 4.0 cm/h for zai, control, stony line and half-moon plots respectively. The pores participating to water transfer also differ. The mean size of drainable pores is 43.7, 56.2, 22.3 and 87.2 pm on control, stony line, half-moon and zai plots respectively.

关键词： Agricultural practice unsaturated hydraulic conductivity sorptivity soil Tougou Burkina Faso.

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