scholarly journals Effects after 1500 Hardening Days on the Microstructure and Durability-Related Parameters of Mortars Produced by the Incorporation of Waste Glass Powder as a Clinker Replacement

2021 ◽  
Vol 13 (7) ◽  
pp. 3979
Author(s):  
Rosa María Tremiño ◽  
Teresa Real-Herraiz ◽  
Viviana Letelier ◽  
Fernando G. Branco ◽  
José Marcos Ortega

One of the ways of lessening the CO2 emissions of cement industry consists of replacing clinkers with supplementary cementitious materials. The required service life of real construction elements is long, so it is useful to characterize the performance of these materials in the very long term. Here, the influence of incorporating waste glass powder as a supplementary cementitious material, regarding the microstructure and durability of mortars after 1500 hardening days (approximately 4 years), compared with reference mortars without additions, was studied. The percentages of clinker replacement by glass powder were 10% and 20%. The microstructure was studied using impedance spectroscopy and mercury intrusion porosimetry. Differential thermal and X-ray diffraction analyses were performed for assessing the pozzolanic activity of glass powder at the end of the time period studied. Water absorption after immersion, the steady-state diffusion coefficient, and length change were also determined. In view of the results obtained, the microstructure of mortars that incorporated waste glass powder was more refined compared with the reference specimens. The global solid fraction and pores volume were very similar for all of the studied series. The addition of waste glass powder reduced the chloride diffusion coefficient of the mortars, without worsening their behaviour regarding water absorption after immersion.

2021 ◽  
Vol 6 (1) ◽  
pp. 10
Author(s):  
Rosa María Tremiño ◽  
Teresa Real-Herraiz ◽  
Viviana Letelier ◽  
José Marcos Ortega

At present, the cement industry still constitutes an important pollutant in the industrial sector. As such, strategies to reduce its environmental impact are a popular research topic. One of these strategies consists of partially replacing clinker with other materials, such as waste glass powder. Here, the effects of the addition of glass powder on the microstructure and durability properties of mortars that incorporate 10% and 20% of this addition as a clinker replacement after 1500 hardening days were analyzed. Reference mortars prepared with ordinary Portland cement without additions were also studied. The mortars were kept in optimum conditions (20 °C and 100% relative humidity) until the testing age. Their microstructure was characterized using mercury intrusion porosimetry and impedance spectroscopy. The steady-state chloride diffusion coefficient and the absorption after immersion were determined as durability parameters. According to the results obtained in the present study, the mortars with the added glass powder showed similar porosities and more refined microstructure compared to the reference mortars. Furthermore, the durability properties of the mortars that incorporate glass powder were similar or even better than those noted for the reference mortars without any additions after 1500 hardening days, especially regarding the resistance against chloride ingress, with the added value of contributing to sustainability.


Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1166 ◽  
Author(s):  
Ahmed Abd El Fattah ◽  
Ibrahim Al-Duais ◽  
Kyle Riding ◽  
Michael Thomas ◽  
Salah Al-Dulaijan ◽  
...  

Reinforcing steel corrosion, caused by chloride ingress into concrete, is the leading cause of reinforced concrete deterioration. One of the main findings in the literature for reducing chloride ingress is the improvement of the durability characteristics of concrete by the addition of supplementary cementitious materials (SCMs) and/or chemical agents to concrete mixtures. In this study, standard ASTM tests—such as rapid chloride permeability (RCPT), bulk diffusion and sorptivity tests—were used to measure concrete properties such as porosity, sorptivity, salt diffusion, and permeability. Eight different mixtures, prepared with different SCMs and corrosion inhibitors, were tested. Apparent and effective chloride diffusion coefficients were calculated using bound chloride isotherms and time-dependent decrease in diffusion. Diffusion coefficients decreased with time, especially with the addition of SCMs and corrosion inhibitors. The apparent diffusion coefficient calculated using the error function was slightly lower than the effective diffusion coefficient; however, there was a linear trend between the two. The formation factor was found to correlate with the effective diffusion coefficient. The results of the laboratory tests were compared and benchmarked to their counterparts in the marine exposure site in the Arabian Gulf in order to identify laboratory key tests to predict concrete durability. The overall performance of concrete containing SCMs, especially fly ash, were the best among the other mixtures in the laboratory and the field.


Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4631 ◽  
Author(s):  
Jingwei Ying ◽  
Zewen Han ◽  
Luming Shen ◽  
Wengui Li

Parent concrete coming from a wide range of sources can result in considerable differences in the properties of recycled coarse aggregate (RCA). In this study, the RCAs were obtained by crushing the parent concrete with water-to-cement ratios (W/Cparent) of 0.4, 0.5 and 0.6, respectively, and were strengthened by carbonation and nano-silica slurry wrapping methods. It was found that when W/Cparen was 0.3, 0.4 and 0.5, respectively, compared with the mortar in the untreated RCA, the capillary porosity of the mortar in the carbonated RCA decreased by 19%, 16% and 30%, respectively; the compressive strength of concrete containing the carbonated RCA increased by 13%, 11% and 13%, respectively; the chloride diffusion coefficient of RAC (DRAC) containing the nano-SiO2 slurry-treated RCA decreased by 17%, 16% and 11%; and that of RAC containing the carbonated RCA decreased by 21%, 25% and 26%, respectively. Regardless of being strengthened or not, both DRAC and porosity of old mortar in RCAs increased with increasing W/Cparent. For different types of RCAs, DRAC increased obviously with increasing water absorption of RCA. Finally, a theoretical model of DRAC considering the water absorption of RCA was established and verified by experiments, which can be used to predict the DRAC under the influence of different factors, especially the water absorption of RCA.


2015 ◽  
Vol 744-746 ◽  
pp. 169-172 ◽  
Author(s):  
Qiao Yang ◽  
Xiao E Zhu

The compressive strengths of the concrete cubes added fly ash were increased 53.2%, the density was almost unchanged, but the water absorption was decreased 30%. The concrete permeability coefficient and chloride diffusion coefficient added fly ash were lower than the common concrete at all ages. The concrete specimens corrosion potential added fly ash were higher than-300mV, while common concrete almost were lower than-500mV. Corrosion probability was small and there was no crack and corrosion pot on the surface of the specimens until 82 times cycles in wet-dry chlorides solution. Fly ash in concrete has obvious act for improving concrete behavior in protecting the embedded steel in corrosion.


2021 ◽  
Vol 894 ◽  
pp. 85-93
Author(s):  
Tanikan Thongchai ◽  
Krisana Poolsawat

This research mainly focused on the properties of decorative white cement tiles which made from waste glass and white cement. The ratio of waste glass powder and white cement were studied at 10 : 90, 15 : 85, 20 : 80, 30 : 70, 40 : 60, 50 : 50, 60 : 40 and 70 : 30 by using water content at 30 %wt. All components were mixed and cast into the mould. Decorative white cement tiles were curing at 14, 21 and 28 days. In order to characterize physical and mechanical properties, all tiles were measured density, water absorption and compressive strength. According to the results, it can be obviously seen that density increased and water absorption decreased with increasing waste glass powder content. The highest compressive strength of around 36.5 MPa was found at 20 %wt of waste glass powder. However, compressive strength decreased with increasing waste glass powder over 20 %wt (waste glass powder 20: white cement 80). It was found that the lowest compressive strength of around 30.58 MPa was found at 70 %wt of waste glass powder. Curing time also affected properties as it was found that increasing curing time to 28 days resulted in increasing of density and compressive strength. In order to study how long does essential oil last on decorative white cement tiles, the orange essential oil at 1, 5 and 10 %wt were added into the white cement paste by using waste glass powder : white cement at 20 : 80 with 30 %wt of water. Decorative white cement tiles were smelled by 30 people every morning for 30 days and it can be found that 10 %wt of orange essential oil last longest on the decorative white cement tiles with 22 days.


2013 ◽  
Vol 405-408 ◽  
pp. 2876-2880
Author(s):  
Jian Bo Xiong ◽  
Peng Ping Li ◽  
Sheng Nian Wang

The influence of mineral admixtures on workability of fresh concrete and chloride ion permeability resistance of hardened concrete for C50 self-compacting concrete was investigated by means of the Natural Immersion Test. The results showed that the chloride diffusion coefficient in fly ash concrete decreased first and then increased with increasing fly ash content in cementitious materials, when fly ash content was 30% or 40%, it got the lowest value at 28 days or 90 days, respectively. The chloride diffusion coefficient in specimens decreased with increasing the ground granulated blast furnace slag content in cementitious materials, but it changed little when the replacement was in ranges of 50% to 60%. Furthermore, for the specimens which replaced by fly ash and ground granulated blast furnace slag, the chloride diffusion coefficient decreased first and then increased with increasing the fly ash content in complex cementitious, and when fly ash content was 10% or 20%, it got the lowest value at 28 days or 90 days, respectively.


2018 ◽  
Vol 926 ◽  
pp. 134-139 ◽  
Author(s):  
Wen Juan Yao ◽  
Lei Fan ◽  
Guang Yan Liu

The hydration products, microstructure and development principle of intensity of cement-glass powder cementitious materials acted in alkali and activation effect of chemical activation on waste glass powder were investigated. The principle of intensity and effect of curing time was analyzed by changing alkali type, content of alkali, incorporation of glass powder, incorporation method of activators and other factor. The result shows that: sodium carbonate and sodium silicate can single stimulate activity of glass powder under a certain condition, the activated effect of combined admixture is superior to the effect on single-doped activator, under the action of an excitation agent, surface hydrolysis of glass powder takes place on the glass body first and the hydration products occurs, The pozzolanic reactivity of glass powder increases gradually and generated a larger amount of hydration products,which has lapped and interlocked growth between each other,and form the compact hardened matrix. In addiation, the shorting of curing time is used by activator, the result may be lead to initial curing and against in engineering construction.


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