Influence of Curing Conditions on Strength Properties and Maturity Development of Concrete

Abstract

IntroductionThe main objectives of this project were to establish a correlation between maturity development and degree of hydration of cement and to establish equivalent curing methods for concrete specimens that can accurately represent the curing conditions of concrete in pavement. To achieve these objectives, the following tasks were performed.1. The maturity development of cement in relation to cement hydration was evaluated. 2. The influences of different specimen curing conditions and specimen types on the flexural strength, compressive strength, and maturity development of pavement concrete were evaluated. FindingsBased on the research results presented in this document, the following conclusions were drawn from the study. 1. There existed a good correlation between maturity development of cement paste and the degree of hydration of cement. This correlation was valid only if sufficient moisture was available for continuous hydration of the specimens. The maturitydegree of hydration correlation could also be extended to concrete since the maturity development in cement paste and concrete was found to be similar. 2. With respect to flexural strength of the specimens, curing specimens in the lime bath or in the sandpit produced specimens with equivalent flexural strengths. Air curing of specimens did not produce specimens with a strength equivalent to the strength of specimens cured in either the lime bath or sandpit. 3. The temperature-matched curing technique was able to produce specimens with strengths within 10 percent of the flexural strength required for opening the pavement to traffic. This result was repeated in the field based on maturity values. 4. With respect to compressive strength, the specimens cured in the sandpit and the specimens cured in air were the most similar. The strengths of the specimens cured in the lime bath were different than the strengths of the specimens cured in the other two curing conditions. 5. The ambient temperature in which the concrete was cured had a significant influence on the maturity development of the concrete. The sandpit-cured specimens most accurately matched the maturity development of the pavement in the field study (within 6 percent). The lime-bath, sandpit and air-cured specimens all matched the maturity of the pavement to within 14 percent. The temperature-match cured specimens matched the maturity development in the pavement to within 1 percent in laboratory studies. 6. It appears that there was no difference between the maturity development in beam specimens and cylinder specimens. Air curing of specimens has a greater effect on the maturity-strength relationship of beam specimens than on cylinder specimens. Also, the temperature match-cured specimens validated the maturity curve for the concrete. 32- ImplementationCurrently INDOT specifies two different types of field curing: lime bath and sandpit curing. Lime bath curing is used for QC/QA pavement construction for specimens made to determine the 7 day flexural strength of the concrete. Sandpit curing...

Experimental Investigation on Field and Laboratory Curing of Natural and Recycled Aggregate Concrete

“…[4] report says a maximum of 15% lower modulus of elasticity of recycled aggregate concrete made with coarse recycled aggregate and natural sand.Seyed-Hassan Bagheri-Zadeh1; Hyoungkwan Kim2; Scott Hounsell3; Charles R. Wood4; Hamid Soleymani5; and Michael King6 (2007) [5] in their paper titled "Field Study of Concrete Maturity Methodology in Cold Weather", they reached to conclusions that, the concrete maturity method has been available for more than50 years, but its actual application in the construction industry has been quite slow.Al-Feel J R1 and Al-Saffar N S2 (2008) [6] in their paper titled "Properties of Self Compacting Concrete at Different Curing Condition and their Comparison with properties of Normal Concrete", concluded that;1) The compressive and tensile strength of Selfcompacting concrete were higher than those of ordinary concrete at all considered ages and for all curing condition The SCC gave high early strength (before 28-days).S. Newbolds1, J. Olek2, (2001) [7] in their research titled "The Influence of Curing Conditions on Strength Properties and Maturity Development of Concrete", concluded that, based on the research results presented in this document. Ronald G. Burg,(1996) [8] in his paper titled "The Influence of Casting and Curing Temperature on the Properties of Fresh and Hardened Concrete", Concluded that based on the results of this laboratory program, 1) As concrete mix temperature is increased from23°C (73"F), slump will decrease approximately 20mm for each 10°C increase in temperature (0.8 in.…”