Reducing Curing Requirements for Pervious Concrete with a Superabsorbent Polymer for Internal Curing

2012 ◽  
Vol 2290 (1) ◽  
pp. 115-121 ◽  
Author(s):  
John T. Kevern ◽  
Chris Farney

This paper presents the results of a research project to investigate reducing the need for curing pervious concrete under plastic by incorporating a superabsorbent polymer (SAP) normally intended for internal curing. Pervious concrete samples were produced with and without the SAP along with additional curing water. Compressive strength, unit weight, voids, and permeability testing was performed on hardened cylinders. Shrinkage was determined on beams for total and autogenous deformation with restrained ring testing. Moisture loss was determined with a modified version of the standard used to evaluate curing compounds, followed by rotary cutter surface abrasion. Field test sections were placed and cured under plastic or left open. The results show that mixtures containing the SAP had better workability and were stronger at equal void contents. The mixture containing the SAP had reduced shrinkage, moisture loss, and abrasion. After one winter, the uncured SAP field mixture had performance equal to the control mixture cured under plastic. Although preliminary, the results show that SAP has good potential to reduce curing requirements for pervious concrete under many environmental conditions.

2021 ◽  
Vol 888 ◽  
pp. 67-75
Author(s):  
Ariel Verzosa Melendres ◽  
Napoleon Solo Dela Cruz ◽  
Araceli Magsino Monsada ◽  
Rolan Pepito Vera Cruz

Chloride ingress into concrete from the surrounding environment can result in the corrosion of the embedded steel reinforcement and cause damage to the concrete. Superabsorbent polymer (SAP) with fine particle size was incorporated into the structure of concrete for controlling the chloride ingress and improving its compressive strength via promotion of internal curing. The SAP used in this study was evaluated for its absorbency property when exposed to cementitious environment such as aqueous solution of Ca (OH)2 and cement slurry. The results were compared to that in sodium chloride solution, the environment where absorbency of most of the SAP found in the market are well studied. Results showed that although SAP absorbency decreased with increasing concentration of Ca (OH)2 and cement, the results suggest that water containing cementitious materials are able to be absorbed by SAP. Chloride ingress into 28-day cured concrete specimens were determined using Rapid Chloride Penetration Test (RCPT) method employing 60V DC driving force. Concrete samples with size of 50 mm height x 100 mm diameter were prepared using a M25 mix design with 0.4 and 0.45 water to cement ratios and different percentages of SAP such as 0.05%, 0.1% and 0.15% with respect to cement mass. Results showed that concrete with 0.15% SAP gave the best result with 14% less chloride permeability than concrete with no SAP for a 0.4 water to cement ratio. Concrete samples for compressive strength tests with size of 200 mm height x 100 mm diameter were prepared using the same mix design and percentages of SAP and cured for 28 days. Results showed that the best results for compressive strength was found at 0.1% SAP at a 0.4 water to cement ratio which can be attributed to internal curing provided by SAP.


2019 ◽  
Vol 276 ◽  
pp. 01025
Author(s):  
Tri Mulyono ◽  
Anisah

The benefit of pervious concrete lies in its ability to transport a large volume of water through its pores to the underlying strata, and it often serves as a pavement for vehicles and pedestrians. This research aimed to determine the properties of pervious concrete based on trials in the laboratory. The method used in this research was a laboratory experiment in accordance with the appropriate standards. The local material used in the mixture was a material composition with Portland Cement Composite with a water-cement (W/C) ratio 0.27 to 0.34, with aggregates of various types and sizes and fly ash and superplasticizer as the added ingredients. The mixture for the trial used 4.25 for the aggregatecement ratio (A/C) with a proportion of 6% for the fine aggregate (sand), 15% flay ash and a low dosage of superplastizer. The test results showed a slight difference in compressive strength and split tensile strength alongside variations in the W/C, including the use of different aggregate types and sizes. The permeability when using natural aggregate was more porous compared to the crushed stone. The effect of the aggregate size from small to large will result in decreased density (unit weight) and increased void in the mixture. Good agreement was reached in the 0.30 wcr mixture with an aggregate size that passed through a 12.5 mm sieve, that was retained at 9.5 mm and that provided suitable compressive strength.


2018 ◽  
Vol 932 ◽  
pp. 136-140
Author(s):  
Mao Chieh Chi ◽  
Jiang Jhy Chang ◽  
Wei Chung Yeih

The purpose of this study is to discuss the properties of low water/cement ratio and high compressive strength pervious concrete. Two sizes of air-cooling electric arc furnace slag (EAFS), for the same size of 0.24 - 0.48 cm and 0.48 - 0.96 cm, were prepared as the coarse aggregates. Two water-to-cement ratios and three filled percentages (70, 80, and 90%) of voids by cement pastes were selected as variables. The unit weight, connected porosity, water permeability coefficient, compressive strength, and flexural strength of pervious concrete were conducted. Test results show that the pervious concrete with higher filled percentage of voids by cement paste has higher unit weight, compressive strength, and flexural strength and smaller connected porosity and water permeability coefficient. The lower the water/cement ratio and EAFS size, the superior the properties. At the water/cement ratio of 0.25, pervious concrete with EAFS size of 0.24 – 0.48 cm and 90% filled percentage of voids by cement pastes had the highest compressive strength of 35 MPa and flexural strength of 7 MPa.


2021 ◽  
Vol 13 (15) ◽  
pp. 8362
Author(s):  
Sung-Il Jeon ◽  
Dong-Hyuk Jung ◽  
Jeong-Hee Nam ◽  
Jae-Myun Nho

In this study, we analyzed the strength and shrinkage properties of concrete with three additives, superabsorbent polymer (SAP), calcium sulfoaluminate (CSA) clinker, and shrinkage-reducing admixture (SRA), to verify the internal curing and shrinkage reduction effects. According to compressive strength tests, the use of SAP as an additive resulted in a slight decrease in compressive strength, whereas using 10% CSA clinker as an additive resulted in a compressive strength 8 MPa higher than that of ordinary concrete. In the shrinkage tests, we observed the shrinkage behavior at the surface and in the middle of the concrete while exposing the surface to ambient air for 80 days. According to the results, SAP and SRA had greater shrinkage reduction effects on the concrete than CSA clinker. In particular, the shrinkage reduction rate achieved by adding SAP to the mixture was approximately 32% compared with ordinary concrete. Based on this result, we concluded that the shrinkage of the mixture reduced due to the internal curing effect (humidity adjustment within the concrete) of the SAP. In addition, the shrinkage reduction effect was maximized when we added these materials simultaneously. In particular, the shrinkage reduction rate achieved by adding SAP and SRA together was found to be approximately 69% compared with ordinary concrete. When we added CSA, SAP, and SRA to the concrete mixture, the shrinkage reduction rate was approximately 96% compared with ordinary concrete, making this the best shrinkage reduction effect achieved.


2021 ◽  
Vol 27 ◽  
pp. 102361
Author(s):  
Lixia Guo ◽  
Fangfang Zhang ◽  
Ling Zhong ◽  
Lei Guo ◽  
Lunyan Wang ◽  
...  

2021 ◽  
Vol 13 (4) ◽  
pp. 2407
Author(s):  
Guang-Zhu Zhang ◽  
Xiao-Yong Wang ◽  
Tae-Wan Kim ◽  
Jong-Yeon Lim ◽  
Yi Han

This study shows the effect of different types of internal curing liquid on the properties of alkali-activated slag (AAS) mortar. NaOH solution and deionized water were used as the liquid internal curing agents and zeolite sand was the internal curing agent that replaced the standard sand at 15% and 30%, respectively. Experiments on the mechanical properties, hydration kinetics, autogenous shrinkage (AS), internal temperature, internal relative humidity, surface electrical resistivity, ultrasonic pulse velocity (UPV), and setting time were performed. The conclusions are as follows: (1) the setting times of AAS mortars with internal curing by water were longer than those of internal curing by NaOH solution. (2) NaOH solution more effectively reduces the AS of AAS mortars than water when used as an internal curing liquid. (3) The cumulative heat of the AAS mortar when using water for internal curing is substantially reduced compared to the control group. (4) For the AAS mortars with NaOH solution as an internal curing liquid, compared with the control specimen, the compressive strength results are increased. However, a decrease in compressive strength values occurs when water is used as an internal curing liquid in the AAS mortar. (5) The UPV decreases as the content of zeolite sand that replaces the standard sand increases. (6) When internal curing is carried out with water as the internal curing liquid, the surface resistivity values of the AAS mortar are higher than when the alkali solution is used as the internal curing liquid. To sum up, both NaOH and deionized water are effective as internal curing liquids, but the NaOH solution shows a better performance in terms of reducing shrinkage and improving mechanical properties than deionized water.


Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4223
Author(s):  
Po-Sung Chen ◽  
Yu-Chin Liao ◽  
Yen-Ting Lin ◽  
Pei-Hua Tsai ◽  
Jason S. C. Jang ◽  
...  

Most high-entropy alloys and medium-entropy alloys (MEAs) possess outstanding mechanical properties. In this study, a series of lightweight nonequiatomic Al50–Ti–Cr–Mn–V MEAs with a dual phase were produced through arc melting and drop casting. These cast alloys were composed of body-centered cubic and face-centered cubic phases. The density of all investigated MEAs was less than 5 g/cm3 in order to meet energy and transportation industry requirements. The effect of each element on the microstructure evolution and mechanical properties of these MEAs was investigated. All the MEAs demonstrated outstanding compressive strength, with no fractures observed after a compressive strain of 20%. Following the fine-tuning of the alloy composition, the Al50Ti20Cr10Mn15V5 MEA exhibited the most compressive strength (~1800 MPa) and ductility (~34%). A significant improvement in the mechanical compressive properties was achieved (strength of ~2000 MPa, strain of ~40%) after annealing (at 1000 °C for 0.5 h) and oil-quenching. With its extremely high specific compressive strength (452 MPa·g/cm3) and ductility, the lightweight Al50Ti20Cr10Mn15V5 MEA demonstrates good potential for energy or transportation applications in the future.


Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 877 ◽  
Author(s):  
Neslihan Doğan-Sağlamtimur ◽  
Ahmet Bilgil ◽  
Magdalena Szechyńska-Hebda ◽  
Sławomir Parzych ◽  
Marek Hebda

Bottom ash (BA) is an industrial solid waste formed by the burning of coal. The environmental problems and storage costs caused by this waste increase with every passing day. In this study, the use of BA as an additive (clay substitute) in fired brick production was investigated. The study consisted of two stages. In the first stage, cylinder blocks were produced from clay used in brick production. The second stage was the examination of the experimental substitution of clay with 10, 20, 30 and 40% BA. Samples were fired at 900, 1000, 1100 and 1150 °C to produce fired brick samples. The unit weight, compressive strength (before and after freeze–thawing) and water absorption were analyzed for the samples. The unit weight values decreased in the samples containing BA. The mechanical properties met the conditions prescribed in the relevant standards; i.e., all of the samples fired at 1100 and 1150 °C had a sufficient compressive strength over 20 MPa. The high potential of fired bricks for the construction industry was proved. BA can be used as a clay substitute, while the developed protocol can be used to effectively produce fired bricks.


2020 ◽  
Vol 846 ◽  
pp. 207-212
Author(s):  
Ming Gin Lee ◽  
Yung Chih Wang ◽  
Wan Xuan Xiao ◽  
Ming Ju Lee ◽  
Tuz Yuan Huang

This study was conducted to assess the effect of CO2 curing on the compressive strength of high strength pervious concrete. The factors studied to evaluate compressive strength of concrete on CO2 curing pressure, curing time, and age of specimen at testing. Three Aggregate sizes, three CO2 curing pressures, three CO2 curing time, and three testing ages were used in this investigation. The research tried to produce a high strength pervious concrete and use carbon dioxide for curing to find out whether it could enhance the compressive strength. The results show that the compressive strength of the control group increases rapidly and its 90-day compressive strength closed to 60 MPa. The 1-day compressive strength has a major impact after CO2 curing and their strength decreased by about 0% to 50% as compared to the control group. However, it is observed that there is only slight difference in relationship between modulus of elasticity and compressive strength obtained from 100 by 200mm cylinders with CO2 curing.


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