Low-temperature curing strength enhancement in cement-based materials containing limestone powder

Abstract

With the ongoing sustainability movement, the incorporation of limestone powder in cementitious binders for concrete in the U.S. has become a subject of renewed interest. In addition to accelerating the early age hydration reactions of cementitious systems by providing additional surfaces for nucleation and growth of products, limestone powder is also intriguing based on its influence on low-temperature curing. For example, previous results have indicated that the utilization of limestone powder to replace one quarter of the fly ash in a high volume fly ash mixture (40 % to 60 % cement replacement) produces a reduction in the apparent activation energy for setting for temperatures below 25 °C. In the present study, the relationship between heat release and compressive strength of mortars at batching/curing temperatures of 10 °C and 23 °C is investigated. For Portland-limestone cements (PLC) with limestone additions on the order of 10 %, a higher strength per unit heat release is obtained after only 7 d of curing in lime water. Surprisingly, in some cases, the absolute strength of these mortar cubes measured at 7 d is higher when cured at 10 °C than at 23 °C. Solubilities vs. temperature, reaction stoichiometries and enthalpies, and projected phase distributions based on thermodynamic modeling for the cementitious phases are examined to provide some theoretical insight into this strength enhancement. For a subset of the investigated cements, thermogravimetric analysis (TGA), quantitative X-ray diffraction (XRD), and scanning electron microscopy (SEM) are conducted on 7-d paste specimens produced at the two temperatures to examine differences in their reaction rates and the phases produced. The strength enhancement observed in the PLC cements is related to the cement hydration products formed in the presence of carbonates as a function of temperature.

Effect of TiO2 Nanoparticles on Physical and Mechanical Properties of Cement at Low Temperatures

“…is is because low temperature restrains the pace of the cement hydration and cement pastes require much longer time to set especially at 0°C. Although the hydration process is demonstrated to proceed at a slower rate in previous study [1,8], low temperature still has a significant impact on the dissolution of clinkers and their reaction with water, resulting in delay in setting time.…”

“…Cement, as one of the most widely used pavement materials, is widely used in pavement engineering because of its low price and easy availability. However, previous studies have demonstrated that low temperature prolongs the setting time of cement and reduces the strength of cement, resulting in lower construction productivity in cold regions [1].…”

“…Calcium nitrate [4,5], aluminate [6], and lithium salts [7] can change the setting time and strength of cement through their chemical properties. In addition, limestone powder [1,8] and silica fume [9] can be used as physical accelerators to modify the cement at low temperatures.…”

RILEM and the National Institute of Standards and Technology (NIST) over the past 50 years

“…Suspension rheology [4][5][6] is discussed, using both experiments and computations. Various aspects of hydration/curing [7][8][9][10][11][12] are explored, again using both experiments and computations. Other topics from this same dual point of view include shrinkage [13][14][15][16], transport (ions, water, heat) [17][18][19][20][21][22][23][24], including probably the first use of Lattice Boltzmann computational methods to construction material application [22,23], and durability/degradation [25][26][27].…”

Compressive Strength Gain Behavior and Prediction of Cement-Stabilized Macadam at Low Temperature Curing

“…Cement-stabilized macadam is low-dose cement-base-stabilized mixture and its cement dosage is 5% or so; it is generally used for base layer of pavement construction in China [1]. Whether or not the compressive strength of cement-based materials largely depends upon the curing process is well known, in which both the curing temperature and time are particularly important [2,3]. For conventional laboratory test of compressive strength, the curing is typically carried in constant temperature environment at 20°C in many national specifications [4][5][6].…”