Chloride content and pH value in the pore solution of concrete under carbonation

A new method involving the extraction of various ions from hardened cement pastes by anhydrous ethanol is presented to determine the pH value and ionic concentration during the first 28 days. The volume content of pore solution extracted by ethanol in the leachate reached 12% or above and the pH values calculated by alkali ions are more than 12, even up to 12.73. The results were compared with those from parallel, conventional pore water expression experiments. All of these comparisons verified the feasibility of the proposed method. However, the application of this method to pore solution analysis needs further improvement.

Download Full-text

Detection of the critical chloride threshold of carbon steel rebar in synthetic concrete pore solutions.

RILEM Technical Letters ◽

10.21809/rilemtechlett.2018.70 ◽

2019 ◽

Vol 3 ◽

pp. 75-83 ◽

Cited By ~ 4

Author(s):

Ibrahim Gbolahan Ogunsanya ◽

Carolyn M. Hansson

Keyword(s):

Carbon Steel ◽

Pore Solution ◽

Input Parameter ◽

Highway Bridges ◽

Chloride Content ◽

Reinforcing Bars ◽

Current Standard ◽

Existing Structures ◽

Essential Input ◽

The Many

Knowledge of the critical chloride content in concrete required to initiate corrosion of reinforcing steel is economically beneficial for the assessment and maintenance of existing structures. Also, many building codes now specify a service life of 75 – 100 years for highway bridges and the critical chloride content is an essential input parameter in the models used in design of structures. There have been numerous studies aimed at determining this parameter but there is no consensus because of the many factors influencing the corrosion. The current standard methods, e.g. ASTM G109, require many weeks or months of testing and are not appropriate for testing large numbers of specimens in different conditions. This project has demonstrated that a fairly rapid potentiodynamic polarization technique can be applied to carbon steel reinforcing bars in synthetic concrete pore solution to determine the critical value, as illustrated in the figure. The importance of selecting the appropriate synthetic concrete pore solution for this application is demonstrated by the different critical values obtained for different solutions. The success of this test will allow the influence of different reinforcing alloys and different cementitious material mixes on the critical chloride content to be determined in a reasonable period of time.

Download Full-text

Influence of Lithium Carbonate on C3A Hydration

Advances in Materials Science and Engineering ◽

10.1155/2018/6120269 ◽

2018 ◽

Vol 2018 ◽

pp. 1-8 ◽

Cited By ~ 1

Author(s):

Weiwei Han ◽

Tao Sun ◽

Xinping Li ◽

Zhonghe Shui ◽

Youzhi Chen ◽

...

Keyword(s):

Pore Solution ◽

Ph Value ◽

Setting Time ◽

Lithium Ion ◽

Mineralogical Composition ◽

Lithium Carbonate ◽

Initial Setting Time ◽

Initial Setting ◽

High Alkalinity ◽

Cement Setting

Lithium salts, known to ameliorate the effects of alkali-silica reaction, can make significant effects on cement setting. However, the mechanism of effects on cement hydration, especially the hydration of C3A which is critical for initial setting time of cement, is rarely reported. In this study, the development of pH value of pore solution, conductivity, thermodynamics, and mineralogical composition during hydration of C3A with or without Li2CO3 are investigated. The results demonstrate that Li2CO3 promotes C3A hydration through high alkalinity, due to higher activity of lithium ion than that of calcium ion in the solution and carbonation of C3A hydration products resulted from Li2CO3. Li2CO3 favors the C3A hydration in C3A-CaSO4·2H2O-Ca(OH)2-H2O hydration system and affects the mineralogical variation of the ettringite phase(s).

Download Full-text

Corrosion Behavior of Steel Reinforcement in Simulated Concrete Pore Solutions with Various pH and Chloride Contents

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.629-630.168 ◽

2014 ◽

Vol 629-630 ◽

pp. 168-172

Author(s):

Shao Heng Hsieh ◽

Ran Huang ◽

Mao Chieh Chi ◽

Pokuei Liang

Keyword(s):

Corrosion Rate ◽

Corrosion Behavior ◽

Pore Solution ◽

Chloride Content ◽

Chloride Ions ◽

Test Results ◽

Weight Loss Measurement ◽

Half Cell ◽

Cell Potential ◽

Significant Factors

Corrosion of rebar in reinforced concrete is a major problem affecting the integrity and loading capacity of the structures. Usually concrete pore solution provides high alkaline environment to protect steel from corrosion. However, the ingress of chloride ions or carbon dioxide would reduce the alkalinity and destroy the stable oxide film which could accelerate the corrosion process of rebar. This study was aimed to evaluate the combined effect of pH and chloride contents on corrosion behavior of rebar using simulated concrete pore solutions. Weight-loss measurement were performed to obtain the corrosion rate. Meanwhile, explore the effect of carbonation and chloride contents to Half-cell potential value on mortar and concrete. Test results show that both pH and chloride content are significant factors influencing the corrosion behavior of rebar. Higher corrosion rate was found in the rebar immersed in the solutions with smaller pH and higher chloride content.

Download Full-text

Sewage Quality Assessment of Various Places in Bilaspur City

International Journal of Sustainable Water and Environmental Systems ◽

10.5383/swes.7.02.008 ◽

2015 ◽

Vol 07 (2) ◽

Author(s):

Ashish Kumar Parashar

Keyword(s):

Suspended Solids ◽

Ph Value ◽

Oxygen Demand ◽

Chloride Content ◽

Temperature Threshold ◽

Test Results ◽

Industrial Growth ◽

Aquatic Life ◽

Physical Tests ◽

And Behavior

The quantity, strength and type of sewage depends upon the population, Life style of people and the existence of different types of industries respectively and the amount of treatment required to be given to sewage depends very much upon the source of disposal. In Bilaspur the source of disposal of municipal as well as industrial waste water is Arpa River (Non perennial) which is known as life line of Bilaspur city. The climatic change has already turned the perennial Arpa River into non Perennial River and at this time the Urbanization, Industrial growth and improved standard of living of people of Bilaspur have increased the strength and quantity of sewage in recent years to a point where dilution alone can no longer be relied upon to prevent the undesirable effect of pollution. Hence it is absolutely necessary to study the characteristics and behavior of sewage, to ensure its safe disposal. This study will help us in determining the degree and type of treatment required to a given sewage according to its characteristics and thus to avoid the pollution of the source of its disposal i.e. Arpa river so that the adverse effect of pollution on human health, aquatic life, animals and plants can be eliminated. For the present study we have selected 4 places in Bilaspur City for collection of sewage hence Sample 1 was collected at Vasant Vihar S.E.C.L. Colony, The sample 2 was collected from M/S Narmada Drinks Pvt. Ltd. Sirgitti, The sample 3 was collected at Pachrighat drain. The sample 4 was collected from Nalla near Bannak Chowk Sirgitti. The Chemical tests namely Suspended Solids, Dissolved Solids, Chloride Content, Chemical Oxygen Demand and Physical tests namely pH value, Temperature, Threshold Odour Number (TON) had been performed and the tests results were compared with Indian standards permissible limits. Priority of this journal is to provide our important and valuable information to all people who show interest. The test results indicated that the Sample-1Vasant Vihar is less polluted, Sample-2 Narmada Drinks only requires neutralization of Chloride Content, Sample-3 Pachrighat was polluted and required treatment in summer season for reducing Solids whereas Sample-4 Bannak Nalla was highly polluted and required throughout treatment of higher degree. Out of the four samples the Sample-4 (Nalla near Bannak Chowk) was found to be most polluted sample in terms of Suspended solids, Chloride content, C.O.D., B.O.D. & T.O.N. and the drain containing this sample is being used by local public and is being discharged untreated into Arpa River. This Wastewater must be treated to prevent the Environment and the water bodies.

Download Full-text

Changes of pore structure and chloride content in cement pastes after pore solution expression

Cement and Concrete Composites ◽

10.1016/j.cemconcomp.2019.103465 ◽

2020 ◽

Vol 106 ◽

pp. 103465 ◽

Cited By ~ 2

Author(s):

Xiang Hu ◽

Caijun Shi ◽

Qiang Yuan ◽

Jian Zhang ◽

Geert De Schutter

Keyword(s):

Pore Structure ◽

Pore Solution ◽

Chloride Content ◽

Cement Pastes

Download Full-text

Physicochemical Analysis and Microbial Diversity of Yamuna Water and Industrial Effluents

International Journal of Applied Sciences and Biotechnology ◽

10.3126/ijasbt.v2i2.10352 ◽

2014 ◽

Vol 2 (2) ◽

pp. 199-205 ◽

Cited By ~ 3

Author(s):

Poonam Gupta ◽

Monika Asthana ◽

Avnish Kumar ◽

Siddhartha Barun

Keyword(s):

Ph Value ◽

Environmental Concern ◽

Bacterial Species ◽

Industrial Effluents ◽

Chloride Content ◽

Physicochemical Analysis ◽

Tannery Effluent ◽

Tannery Effluents ◽

Textile Effluents ◽

Standard Values

Pollution has arisen as a serious environmental concern to the present world after industrialization of human societies. It has severely affected our air, soil and water sources. Looking to its global, national, regional and local dimensions, it is now imperative to check it at each and every level. In the present study, 8 samples (3 Yamuna water samples, 3 tannery effluent samples and 2 textile effluent samples), were collected from different sites of Yamuna and exit points of textile and tannery Industries. Water and effluent samples were analysed for various physicochemical parameters (pH, TDS, hardness, chloride and BOD) using conventional methods. Afterwards these samples were utilized for isolation of the native bacterial species. All the samples were showing higher than the standard values for TDS (500mg/l), hardness (80-100 mg/l), chloride (250mg/l) and BOD (30mg/l). It was observed that the tannery effluents were showing maximum TDS values(1190-1240mg/l), followed by textile effluents (1190 and 1210mg/l) and Yamuna water (530-1180mg/l).Similarly, in case of chloride content, highest concentration range(828.8-1598mg/l)was shown by tannery effluents. pH value was nearly neutral for Yamuna water, slightly acidic in case of textile effluents and more acidic for tannery samples. Highest range of hardness values were observed for the tannery effluents (860-880mg/l) followed by textile effluents (760 and 860mg/l). The BOD values were nearly similar for all the samples with maximum values being observed for tannery effluents (42-48 mg/l). Thus it can be inferred that all the samples were highly polluted and need to be treated by suitable methods. There were 11 cultures purified, that could be employed in bioremediation purposes.DOI: http://dx.doi.org/10.3126/ijasbt.v2i2.10352Int J Appl Sci Biotechnol, Vol. 2(2): 199-205

Download Full-text

Influence of the nature of organic compounds on fine soil stabilization with cement

Canadian Geotechnical Journal ◽

10.1139/t02-002 ◽

2002 ◽

Vol 39 (3) ◽

pp. 535-546 ◽

Cited By ~ 128

Author(s):

Hélène Tremblay ◽

Josée Duchesne ◽

Jacques Locat ◽

Serge Leroueil

Keyword(s):

Organic Matter ◽

Shear Strength ◽

Organic Compounds ◽

Soil Stabilization ◽

Pore Solution ◽

Ph Value ◽

Organic Matter Content ◽

Undrained Shear Strength ◽

Chemical Analyses ◽

Undrained Shear

It is well known that organic matter may affect the cementing process in soils, but what happens when cement is added to an organic soil? Both the organic matter content and the nature of this organic matter affect the properties of a treated soil. It appears that some organic compounds delay or even inhibit the hydration process of cement, while others do not affect the reaction at all. This paper presents some results of a laboratory study in which 13 different organic compounds were added separately to two different soils, and then treated with 10% cement. To assess the cementing process, undrained shear strength was measured on the different specimens, and some chemical analyses were performed on the pore liquid. The results indicate that the organic acids producing a pH lower than 9 in the pore solution strongly affect the development of cementing products and almost no strength gain was noted. Also, oils and hydrocarbons, which are insoluble in water, delay the cement hydration but do not affect the final strength. Finally, the pH value and the SO4 concentration in the pore solution are good indicators of the cementing effectiveness of the treated specimens.Key words: soil stabilization, organic compounds, undrained shear strength, cement, chemical analyses.

Download Full-text

Effect of Composition of Cementitious Materials on Alkalinity of Pore Solution and Strength of Cement Paste

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.671-674.1732 ◽

2013 ◽

Vol 671-674 ◽

pp. 1732-1735

Author(s):

Xiao Lu Yuan ◽

Shi Hua Zhou ◽

Dong Mei Liu

Keyword(s):

Compressive Strength ◽

Cement Paste ◽

Pore Solution ◽

Ph Value ◽

Cement Content ◽

Cementitious Materials ◽

Mineral Admixtures ◽

Aluminate Cement

Alkalinity of the surroundings is the basis to study the MICP technology. Alkalinity of pore solution and strength of cement paste made of various cementitious materials were studied. Results show that the alkalinity of pore solution of cement paste decreased with the increase of sulpho-aluminate cement content. pH value of cement paste was about less than 10 when sulpho-aluminate cement content exceeded 75%. Incorporation of sulpho-aluminate cement decreased compressive strength of paste obviously; however, compressive strength of paste was improved when the addition of sulpho-aluminate cement was more than 75%. Addition of mineral admixtures reduced the alkalinity of pore solution of cement paste and increased its compressive strength. Compressive strength of specimens was decreased when the content of mineral admixtures increased.

Download Full-text