scholarly journals A Method for Internal Curing Water Calculation of Concrete with Super Absorbent Polymer

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Shouqi Zhang ◽  
Zhenbao Lu ◽  
Yongxin Li ◽  
Yuan Ang ◽  
Kechao Zhang
Keyword(s):  
Phase Distribution ◽  
Autogenous Shrinkage ◽  
Mineral Admixture ◽  
Internal Curing ◽  
Hardened Concrete ◽  
Hardened Cement ◽  
Cement Pastes ◽  
Super Absorbent Polymer ◽  
Degree Of Hydration ◽  
Absorbent Polymer

The internal curing method is effective in reducing the self-desiccation of concrete, and the amount of internal curing water (IC water) is greatly important to the shrinkage and strength of concrete. A method for calculating IC water of concrete with and without mineral admixture has been developed. The method is derived from Powers’ model for the phase distribution of a hydrating cement paste. To verify the method, a series of autogenous shrinkage and compressive strength of concrete with and without super absorbent polymer (SAP) were evaluated compared with the method proposed previously. To explain the macro performance of hardened concrete, the nonevaporable water content and calcium hydroxide content measurement were utilized to evaluate the degree of hydration of cement pastes. And, mercury intrusion method and image analysis method were used to explore the pore structure in hardened cement pastes and air void characteristics in hardened concrete, respectively. Furthermore, the evolution process was also studied for the relative humidity inside the concrete.

scholarly journals Effect of Internal Curing by Super Absorbent Polymer on the Autogenous Shrinkage of Alkali-Activated Slag Mortars

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4318
Author(s):  
Pengju Wang ◽  
Haiming Chen ◽  
Peiyuan Chen ◽  
Jin Pan ◽  
Yangchen Xu ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Setting Time ◽  
Autogenous Shrinkage ◽  
Internal Curing ◽  
Engineering Properties ◽  
Super Absorbent Polymer ◽  
Alkali Activated Slag ◽  
Activated Slag ◽  
Absorbent Polymer ◽  
Alkali Activated

Alkali activated slag (AAS) mortar is becoming an increasingly popular green building material because of its excellent engineering properties and low CO2 emissions, promising to replace ordinary Portland cement (OPC) mortar. However, AAS’s high shrinkage and short setting time are the important reasons to limit its wide application in engineering. This paper was conducted to investigate the effect of internal curing(IC) by super absorbent polymer (SAP) on the autogenous shrinkage of AAS mortars. For this, an experimental study was carried out to evaluate the effect of SAP dosage on the setting time, autogenous shrinkage, compressive strength, microstructure, and pore structure. The SAP were incorporated at different dosage of 0, 0.05, 0.1, 0.2, 0.3, 0.4, and 0.5 percent by weight of slag. The workability, physical (porosity), mechanical, and shrinkage properties of the mortars were evaluated, and a complementary study on microstructure was made. The results indicated that the setting time increased with an increase of SAP dosage due to the additional activator released by SAP. Autogenous shrinkage decreased with an increase of SAP dosage, and was mitigated completely when the dosage of SAP ≥ 0.2% wt of slag. Although IC by means of SAP reduced the compressive strength, this reduction (23% at 56 days for 0.2% SAP) was acceptable given the important role that it played on mitigating autogenous shrinkage. In the research, the 0.2% SAP dosage was the optimal content. The results can provide data and basis for practical application of AAS mortar.

scholarly journals Efficiency of Sodium Polyacrylate to Improve Durability of Concrete under Adverse Curing Condition

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Tanvir Manzur ◽  
Shohana Iffat ◽  
Munaz Ahmed Noor
Keyword(s):  
Internal Curing ◽  
Curing Agent ◽  
Sodium Polyacrylate ◽  
Curing Process ◽  
Super Absorbent Polymer ◽  
Curing Conditions ◽  
Naturally Occurring ◽  
Additional Water ◽  
Strength And Durability ◽  
Absorbent Polymer

The conventional external curing process requires supply of large amount of water in addition to mixing water as well as strict quality control protocol. However, in a developing country like Bangladesh, many local contractors do not have awareness and required knowledge on importance of curing which often results in weaker concrete with durability issues. Moreover, at times it is difficult to maintain proper external curing process due to nonavailability of water and skilled laborer. Internal curing can be adopted under such scenario since this method is simple and less quality intensive. Usually, naturally occurring porous light weight aggregates (LWA) are used as internal curing agent. However, naturally occurring LWA are not available in many countries like Bangladesh. Under these circumstances, Super Absorbent Polymer (SAP) can be utilized as an alternative internal curing agent. In this study, sodium polyacrylate (SP) as SAP has been used to produce internally cured concrete. Desorption isotherm of SP has been developed to investigate its effectiveness as internal curing agent. Test results showed that internally cured concrete with SP performed better in terms of both strength and durability as compared to control samples when subjected to adverse curing conditions where supply of additional water for external curing was absent.

Chemical Shrinkage of Pastes Made with Shrinkage Reducing Admixtures

2011 ◽  
Vol 466 ◽  
pp. 105-113 ◽  
Author(s):  
António Bettencourt Ribeiro ◽  
Vasco Medina ◽  
Augusto Gomes ◽  
Arlindo Gonçalves
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Autogenous Shrinkage ◽  
Drying Shrinkage ◽  
Chemical Shrinkage ◽  
Cement Pastes ◽  
Degree Of Hydration ◽  
Shrinkage Cracks ◽  
Large Application ◽  
Shrinkage Reducing Admixtures

Shrinkage Reducing Admixtures (SRA) are being used more often in concrete structures in order to better control shrinkage cracks. High-performance concrete, nowadays with large application, has more proneness to crack at very early age due to the lower W/C. In this type of concrete, autogenous shrinkage is usually more important than drying shrinkage. Autogenous shrinkage is due to the volume decrease inherent to binder hydration reactions. The rate of these reactions is influenced not only by the type of binder but also by the presence of chemical admixtures. It is recognized that SRA delay the hydration, being a secondary effect of this type of admixtures. In this work changes on the degree of hydration of cement pastes with SRA and different binders are presented, using the chemical shrinkage test.

scholarly journals Eliminating the Shrinkage of High Strength Concrete by using Super Absorbent Polymer (SAP)

2018 ◽  
Vol 11 (4) ◽  
pp. 8-13
Author(s):  
Baidaa Khdheer Ahmed
Keyword(s):  
Compressive Strength ◽  
High Strength Concrete ◽  
Autogenous Shrinkage ◽  
Drying Shrinkage ◽  
High Strength ◽  
Super Absorbent Polymer ◽  
Strength Concrete ◽  
Group A ◽  
Group B ◽  
Absorbent Polymer

High Strength Concrete (HSC) is one of the  most popular types of concrete used in the world. This type of concrete has a low rapid  hydration of cementation materials with low  w/cm and the external surrounding  environment condition exposed the HSC to  high autogenous shrinkage. If this shrinkage is  not treated well that well led to cracking, in  this case HSC need to convenient curing  necessary at the earliest time. This study  presents the use of Super Absorbent Polymer  (SAP) as internal curing agent to eliminate  shrinkage. Two types of shrinkage are tested in  this study (Autogenous shrinkage and drying  shrinkage).  Two groups of concrete mixes(A and B) are  studied in this study each group have five types  of concrete mixes, four mixes with high and  ultra-high compressive strength (RPC, MRPC, HSC and SCC) and the last one with normal  compressive strength (NSC). Group A  represent concrete mixes without SAP addition  and group B for concrete mixes with SAP.  SAP was added for all mixes at 0.3% by  weight of cement and adding 20ml water for  each gram of SAP, specimens with dimensions  (40*40*160) mm were used for testing  shrinkage for each mix with and without SAP,  average values for two specimens was taken as  a results. It was found that concrete mixes of  group B have lower shrinkage than the  shrinkage of concrete mixes in group A at 28  days age with reduction of autogenous  shrinkage(AS) of (57%, 35%, 37%, 44.5% and  37.5%) respectively and for drying shrinkage  the percentage of reduction was (89.5%, 72%,  82%, 70% and 71%) respectively, addition of  SAP to concrete mixes proves to have active  effect in reducing the shrinkage of concrete.

Effect of Curing Methods on Strength and Durability Properties of M30 Grade Concrete

2021 ◽  
Vol 9 (11) ◽  
pp. 1386-1389
Author(s):  
Chidananda G
Keyword(s):  
Compressive Strength ◽  
Fresh Concrete ◽  
Hardened Concrete ◽  
Concrete Compressive Strength ◽  
Super Absorbent Polymer ◽  
Carbonation Resistance ◽  
Curing Methods ◽  
Water Curing ◽  
Strength And Durability ◽  
Absorbent Polymer

Abstract: This paper presents an experimental investigation on influence of different curing methods on the performance of M30 grade concrete. Different curing methods such as air curing, pond curing, intermittent curing, gunny bags curing, chemical curing and using Super Absorbent Polymer (SAP) by 0.3% of weight of cement are considered. Slump and compacting factor tests are performed to know the workability of fresh concrete. Compressive strength of hardened concrete is determined for concrete specimens cured by different curing methods. Durability in terms of carbonation resistance on hardened concrete is also performed as per IS 516 (Part 5/Sec 3, 2021) codal provisions. Depending upon the site conditions and availability of potable water, curing methods such as pond curing, intermittent curing, gunny bags curing, chemical curing and SAP curing can be adopted in site to achieve the expected strength and durability requirements. Keywords: Curing methods, Compressive strength and Carbonation resistance.

Effects of Internal Curing by Super Absorbent Polymer on Shrinkage of Concrete

2011 ◽  
Vol 477 ◽  
pp. 200-204 ◽  
Author(s):  
Lu Feng Pang ◽  
Shi Ye Ruan ◽  
Yong Tao Cai
Keyword(s):  
Cement Mortar ◽  
Internal Curing ◽  
Blank Group ◽  
Super Absorbent Polymer ◽  
Absorbent Polymer

This paper focuses on the shrinkage of concrete, influenced by the different mixing amount of super absorbent polymer—SAP and extra-water. The experiment showed that the SAP-cement-mortar shrinkage is reduced greatly by mixing SAP. Extra-water can improve the function of reducing shrinkage of SAP. When the amount is 20, the shrinkage is lest, account for 57% of blank group’s. The SAP has well effect on the cement mortar shrinkage. Besides, we found that the strength of this group account for 89% of blank group. So the proper amount of SAP and extra-water has poorly influence on the strength of concrete.

scholarly journals Performance of super-absorbent polymer as an internal curing agent for self-compacting concrete

2018 ◽  
Vol 162 ◽  
pp. 02023 ◽  
Author(s):  
Suhair Al-Hubboubi ◽  
Tareq al-Attar ◽  
Haider Al-Badry ◽  
Samir Abood ◽  
Rawaa Mohammed ◽  
...  
Keyword(s):  
Fresh Concrete ◽  
Internal Curing ◽  
Curing Agent ◽  
Self Compacting Concrete ◽  
Super Absorbent Polymer ◽  
Strength Tests ◽  
Fresh State ◽  
Concrete Mix ◽  
Water Curing ◽  
Absorbent Polymer

Internal curing agent by using super-absorbent polymer was present in this study, its effect on the properties of self-compacting concrete was evaluated .The SAP content in the concrete mix was 0.5 % by weight of cement. Three procedures for curing were adopted; curing in water, curing in water and air and curing in polyethylene sealed bags. Fresh concrete tests conducted to assess the self-compactability of the produced concrete. Moreover, compressive and splitting strength tests were carried out. The testing program had been extended to the age of 90 days.The use of super-absorbent polymer did not affect the fresh state characteristics of the studied SCC and achieved an increase in both compressive and tensile strengths as compared to the reference concrete mix.

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