The effect of a proprietary inorganic coating on compressive strength and carbonation depth of simulated fire-damaged concrete

2013 ◽  
Vol 65 (11) ◽  
pp. 651-659 ◽  
Author(s):  
Qingtao Li ◽  
Zhuguo Li ◽  
Guanglin Yuan ◽  
Qianjin Shu
Keyword(s):  
Compressive Strength ◽  
Carbonation Depth ◽  
Inorganic Coating ◽  
Simulated Fire

scholarly journals Carbonization Durability of Two Generations of Recycled Coarse Aggregate Concrete with Effect of Chloride Ion Corrosion

2020 ◽  
Vol 12 (24) ◽  
pp. 10544
Author(s):  
Chunhong Chen ◽  
Ronggui Liu ◽  
Pinghua Zhu ◽  
Hui Liu ◽  
Xinjie Wang
Keyword(s):  
Compressive Strength ◽  
Coarse Aggregate ◽  
Chloride Ion ◽  
Total Porosity ◽  
Recycled Concrete ◽  
Carbonation Depth ◽  
Aggregate Concrete ◽  
Recycled Coarse Aggregate ◽  
Carbonation Resistance ◽  
Two Generations

Carbonation durability is an important subject for recycled coarse aggregate concrete (RAC) applied to structural concrete. Extensive studies were carried out on the carbonation resistance of RAC under general environmental conditions, but limited researches investigated carbonation resistance when exposed to chloride ion corrosion, which is an essential aspect for reinforced concrete materials to be adopted in real-world applications. This paper presents a study on the carbonation durability of two generations of 100% RAC with the effect of chloride ion corrosion. The quality evolution of recycled concrete coarse aggregate (RCA) with the increasing recycling cycles was analyzed, and carbonation depth, compressive strength and the porosity of RAC were measured before and after chloride ion corrosion. The results show that the effect of chloride ion corrosion negatively affected the carbonation resistance of RAC, and the negative effect was more severe with the increasing recycling cycles of RCA. Chloride ion corrosion led to a decrease in compressive strength, while an increase in carbonation depth and the porosity of RAC. The equation of concrete total porosity and carbonation depth was established, which could effectively judge the deterioration of carbonation resistance of RAC.

scholarly journals Effects of Environmental Factors on Concrete Carbonation Depth and Compressive Strength

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2167 ◽  
Author(s):  
Ying Chen ◽  
Peng Liu ◽  
Zhiwu Yu
Keyword(s):  
Compressive Strength ◽  
Phase Composition ◽  
Relative Humidity ◽  
Co2 Concentration ◽  
Crystal Structure Analysis ◽  
Hydration Products ◽  
Carbonation Depth ◽  
Concrete Carbonation ◽  
Before And After ◽  
Compressive Strength Of Concrete

The influence of temperature, CO2 concentration and relative humidity on the carbonation depth and compressive strength of concrete was investigated. Meanwhile, phase composition, types of hydration products and microstructure characteristics of samples before and after the carbonation were analyzed by XRD and ESEM. Research results demonstrate that temperature, CO2 concentration and relative humidity influence the carbonation depth and compressive strength of concrete significantly. There is a linear relationship between temperature and carbonation depth, as well as the compressive strength of concrete. CO2 concentration and relative humidity present a power function and a polynomial function with carbonation depth of concrete, respectively. The concrete carbonation depth increases with the increase of relative humidity and reaches the maximum value when the relative humidity is 70%. Significant differences of phase composition, hydration products and microstructure are observed before and after the carbonation. Carbonization products of samples are different with changes of temperatures (10 °C, 20 °C and 30 °C). The result of crystal structure analysis indicates that the carbonation products are mainly polyhedral spherical vaterite and aragonite.

scholarly journals Effect of Soorh Metakaolin on Concrete Compressive Strength and Durability

2017 ◽  
Vol 7 (6) ◽  
pp. 2210-2214 ◽  
Author(s):  
A. Saand ◽  
M. A. Keerio ◽  
D. K. Bangwar
Keyword(s):  
Compressive Strength ◽  
Corrosion Resistance ◽  
Life Time ◽  
Natural Material ◽  
Concrete Durability ◽  
Concrete Compressive Strength ◽  
Water Penetration ◽  
Carbonation Depth ◽  
Ordinary Concrete ◽  
Strength And Durability

Concrete durability is a key aspect for forecasting the expected life time of concrete structures. In this paper, the effect of compressive strength and durability of concrete containing metakaolin developed from a local natural material (Soorh of Thatta Distict of Sindh, Pakistan) is investigated. Soorh is calcined by an electric furnace at 8000C for 2 hours to produce metakaolin. One mix of ordinary concrete and five mixes of metakaolin concrete were prepared, where cement is replaced by developed metakaolin from 5% to 25% by weight, with 5% increment step. The concrete durability was tested for water penetration, carbonation depth and corrosion resistance. The obtained outcomes demonstrated that, 15% replacement level of local developed metakaolin presents considerable improvements in concrete properties. Moreover, a considerable linear relationship was established between compressive strength and concrete durability indicators like water penetration, carbonation depth and corrosion resistance.

Influence the Carbonation Resistance and Mechanical Properties of Shotcrete by Accelerated Carbonation Test

2014 ◽  
Vol 1065-1069 ◽  
pp. 1985-1989
Author(s):  
Jia Bin Wang ◽  
Di Tao Niu ◽  
Rui Ma ◽  
Ze Long Mi
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Steel Fiber ◽  
Splitting Tensile Strength ◽  
Construction Technology ◽  
Accelerated Carbonation ◽  
Carbonation Depth ◽  
Normal Concrete ◽  
Carbonation Resistance

In order to investigate the carbonation resistance of shotcrete and the mechanical properties after carbonation, the accelerated carbonation test was carried out. The results indicate that the carbonation resistance of shotcrete is superior to that of normal concrete. With the increasing of carbonation depth, compressive strength and splitting tensile strength of shotcrete grew rapidly. The admixing of steel fiber can further improve the carbonation resistance, reduce the carbonation rate, and increase the splitting tensile strength of shotcrete greatly. Besides, based on analyzing the effects of construction technology and steel fiber of concrete for the carbonation resistance, a carbonation depth model for shotcrete was established. Key words: shotcrete; carbonation; steel fiber; mechanical properties

scholarly journals PROPERTIES OF CEMENT-FLY ASH MIXTURES WITH SUBSTANDARD FLY ASH AS A PARTIAL CEMENT AND FINE AGGREGATE REPLACEMENT

2021 ◽  
Vol 11 (3) ◽  
pp. 71-88
Author(s):  
Piseth Pok ◽  
Parnthep Julnipitawong ◽  
Somnuk Tangtermsirikul
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Sulfate ◽  
Chloride Penetration ◽  
The Other ◽  
Fine Aggregate ◽  
Carbonation Depth ◽  
Cement Replacement ◽  
Durability Properties ◽  
Compressive Strength Of Concrete

This research investigated the effects of using a substandard fly ash as a partial cement and/or fine aggregate replacement on the basic and durability properties of cement-fly mixtures. Experimental results showed that utilizing the substandard fly ash led to increase in water requirement and autoclave expansion of pastes. The strength activity indexes of the substandard fly ash passed the requirements of TIS 2135 and ASTM C618. Utilization of the substandard fly ash as cement replacement led to higher expansion of mortar bars stored in water and sodium sulfate expansion as compared to that of the OPC mixture. However, sodium sulfate resistance of mortar mixtures improved when utilizing the substandard fly ash as sand replacement material. The compressive strength of concrete at all ages was higher with the increase of the content of the substandard fly ash as sand replacement material. When the substandard fly ash was used as cement replacement material in concrete, the carbonation depth increased. On the other hand, the use of the substandard fly ash as sand replacement material decreased the carbonation depth of the concrete. Utilization of the substandard fly ash, both to replace cement and/or fine aggregate, reduced the rapid chloride penetration of the concrete.

scholarly journals Carbonation Resistance in Ordinary Portland Cement Concrete with and without Recycled Coarse Aggregate in Natural and Simulated Environment

2021 ◽  
Vol 14 (1) ◽  
pp. 437
Author(s):  
Wajeeha Mahmood ◽  
Asad-ur-Rehman Khan ◽  
Tehmina Ayub
Keyword(s):  
Carbon Dioxide ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Natural Environment ◽  
Coarse Aggregate ◽  
Splitting Tensile Strength ◽  
Carbonation Depth ◽  
Simulated Environment ◽  
Concrete Mix ◽  
Carbon Dioxide Co2

This research aims to examine the effect of carbonation on the strength properties and carbonation depth of ordinary Portland cement (OPC) concrete using two different water to cement ratios (w/c) and two different replacement percentages of natural coarse aggregate (NCA) with recycled coarse aggregate (RCA). Two concrete mixes were prepared using w/c of 0.4 and 0.43. The two concrete mixes were subdivided into two subgroups based on the use of NCA and 30% RCA. The first concrete mix having w/c of 0.4 was contained NCA and from this concrete, 42 cylinders of 100 mm dia. and 200 mm height were cast. Six out of 42 cylinders served as control specimens and were not exposed to CO2. A total of 18 out of the remaining 36 cylinders was exposed to the simulated environment and the rest were exposed to the natural environment. The second concrete mix having a w/c of 0.4 contained 30% RCA/70% NCA, and using this concrete, 42 cylinders of similar size were cast. A similar scheme was adopted for w/c of 0.43 and, in total, 84 cylinders using four mix designs were cast. After casting and 28 days of curing, six out of 42 cylinders cast from each concrete mix design were tested for compression and splitting tensile strength, following ASTM C39 and ASTM C496 without any exposure to carbon dioxide (CO2). A total of 18 out of the remaining 36 cylinders was exposed to the simulated environment in a carbonation chamber for an equivalent time duration of 90, 180 and 365 days following CEN test guidelines and the other 18 cylinders were kept in the natural environment for a period of 90, 180 and 365 days. After the completion of simulated and natural exposure periods, these cylinders were distributed equally to test for compressive strength and splitting tensile strength to observe the effect of carbon dioxide (CO2) at each time duration (i.e., 90, 180 and 365 days), and replacement percentage of RCA (i.e., 0 and 30%), which showed that carbonation depth increases incrementally with the w/c ratio and CO2 exposure duration. In both the simulated and the natural environment, the use of RCA in concrete cast using a w/c of 0.4 increased carbonation depth up to 38% and 46%, whereas, in the case of the concrete cast using a w/c ratio of 0.43, the use of RCA increased the carbonation depth up to 16% and 25%. In general, the use of RCA in the concrete exposed to the natural environment significantly affected the compressive strength of concrete, due to multiple interfaces and the porous structure of RCA, and the variation in the temperature, humidity and content of carbon dioxide (CO2) present in the actual environment. The maximum compressive strength variation prepared from the mixes M0-0.4, M30-0.43, M0-0.43 and M30-0.43 differed by 5.88%, 7.69%, 16.67% and 20% for an exposure period up to 365 days. Similarly, the results of splitting tensile strength tests on cylinders prepared from the same mixes exposed to the natural environment differ by 7.4%, 27.6%, 25.41% and 18.2% up to 365 days of exposure, respectively, as compared to the simulated environment.

scholarly journals Physicochemical Properties of Hydrated Portland Cement Blended with Rice Husk Ash

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Joseph Mwiti Marangu ◽  
Cyprian Muturia M’thiruaine ◽  
Mark Bediako
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Rice Husk ◽  
Elevated Temperatures ◽  
Rice Husk Ash ◽  
Blended Cement ◽  
Strength Development ◽  
Carbonation Depth ◽  
Blended Cements ◽  
Carbonation Resistance

In the presence of significant quantities of carbon dioxide (CO2) and elevated temperatures in the atmosphere due to climate change, cement-based materials are susceptible to carbonation. Blended cements are more prone to carbonation attack than Portland cement. There is a need to evaluate the carbonation resistance of blended cements in a carbonation-prone environment. This paper presents experimental findings obtained from an evaluation of carbonation resistance tests on Rice Husk Ash- (RHA-) blended cement. The blended cement was made by intergrinding of Portland Cement (PC) and RHA to make the test cement (PC-RHA). The RHA dosage in the PC-RHA was varied from 0 to 30% by mass of PC. Pozzolanicity, standard consistency, and setting time tests were conducted on PC-RHA. Mortar prisms measuring 160 mm × 40 mm x 40 mm were separately cast at a water/cement ratio ( w / c ) of 0.50 and 0.60 and cured in water for 2, 7, 14, 28, and 90 days. Compressive strength tests were conducted on the mortar prisms at each of the testing ages. The prepared mortars were also subjected to accelerated carbonation tests in two Relative Humidity (RH) curing regimes, one maintained at an RH greater than 90% and the other between 50–60%. Carbonation resistance of the mixtures was evaluated in terms of the changes in carbonation depth using a phenolphthalein test at the age of 7, 14, 28, and 56 days of curing in a continuous flow of CO2. Compressive strength measurements were also taken during each of the carbonation testing ages. For comparison, similar tests were conducted using commercial PC. The results showed that PC-RHA was pozzolanic while PC was nonpozzolanic. Higher water demand and longer setting times were observed in PC-RHA than in PC. Moreover, there was increased strength development in water-cured samples with increased curing duration. Carbonation results indicated that there was a marked increase in carbonation depth with increased dosage of RHA in PC-RHA binders, increased duration of exposure to CO2, and decreased RH (RH between 50–60%). PC-RHA binders exhibited lower carbonation resistance than PC. In conclusion, for mortars at any w / c ratio, carbonation resistance decreased with increase in RHA dosage and increased w / c ratio.

Anthropogenic Carbon Aerosol Induced Carbonation in Reinforced Concrete: Deterioration Effects on Mechanical Properties

2021 ◽  
Vol 57 ◽  
pp. 139-148
Author(s):  
O.E. Babalola ◽  
Paul O. Awoyera ◽  
D.H. Le ◽  
Oladimeji B. Olalusi ◽  
S.K. Bhagat
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Reinforced Concrete ◽  
Black Carbon ◽  
Mass Concrete ◽  
Carbonation Depth ◽  
Concrete Deterioration ◽  
Carbon Soot ◽  
Anthropogenic Carbon

The effects of corrosion on the reinforced concrete structure due to carbonation affect its operation life. The research work considers a major critical component causing global warming as it studies the links between reinforced concrete deterioration mechanisms and anthropogenic carbon aerosol (black carbon soot) emissions in the atmosphere. Experimental tests were carried out to study the effect of carbonation caused by the emission of black carbon soot on mechanical properties and durability of reinforced concrete. Mass concrete and reinforced concrete prepared with Ordinary Portland cement (OPC) in water/cement ratios ranging from 0.45 to 0.65 were used to produce concrete samples. Compressive strength tests, tensile strength test, and carbonation depth tests were carried out on concrete to determine its level of deterioration following the carbonation effect. The carbonation chamber was prepared with carbon soot of different concentrations to simulate different levels of black carbon soot in the atmosphere. Results showed that concrete compressive strength was not totally affected by carbonation, but there was reduction in the tensile strength of reinforcing steel. The carbonation depth was observed to progress deeper into the concrete with a longer duration of exposure to carbonation agents in the chamber. The result of this study will serve as a guide during concrete installations.

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