Experimental investigation on the influence of phase change materials on properties and pore structure of steam-cured mortar

Bi, Liping; Long, Guangcheng; Ma, Cong

doi:10.1007/s43452-020-00170-7

Cited by 6 publications

(2 citation statements)

References 26 publications

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“…[57] utilized organic PCM (polyethylene glycol), and reported its considerable compatibility in filling micropores and cracks of hardened concrete. Similarly, Bi et al [58], used paraffin as PCM and reported significant reduction of water absorption and associated it with the improvement of hydrophobic characteristics in the pores when PCM are used. This can be better seen in Figure 8b that shows capillary water absorption.…”

Section: Water Absorptionmentioning

confidence: 99%

Foam Concrete Produced with Recycled Concrete Powder and Phase Change Materials

et al. 2022

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In construction industry, phase change materials (PCMs), have recently been studied and found effective in increasing energy efficiency of buildings through their high capacity to store thermal energy. In this study, a combination of Capric (CA)-Palmitic acid (PA) with optimum mass ratio of 85–15% is used and impregnated with recycled concrete powder (RCP). The resulting composite is produced as foam concrete and tested for a series of physico-mechanical, thermal and microstructural properties. The results show that recycled concrete powder can host PCMs without leaking if used in proper quantity. Further, the differential scanning calorimetry (DSC) results show that the produced RCP/CA-PA composites have a latent heat capacity of 34.1 and 33.5 J/g in liquid and solid phases, respectively, which is found to remain stable even after 300 phase changing cycles. In this regard, the indoor temperature performance of the rooms supplied with composite foams made with PCMs, showed significantly enhanced efficiency. In addition, it is shown that inclusion of PCMs in foam concrete can significantly reduce porosity and pore connectivity, resulting in enhanced mechanical properties. The results are found promising and point to the suitability of using RCP-impregnated PCMs in foam composites to enhance thermo-regulative performance of buildings. On this basis, the use of PCMs for enhanced thermal properties of buildings are recommended, especially to be used in conjunction with foam concrete.

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Section: Water Absorptionmentioning

confidence: 99%

Foam Concrete Produced with Recycled Concrete Powder and Phase Change Materials

et al. 2022

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“…However, there are still insufficient researches on the influence of diameter of FRP bars, anchorage length and thickness of concrete protective layer on the bond performance of GFRP bars under steam curing environment, thus increasing the investment of steamcured concrete in Engineering practice. However, in the steaming environment, the concrete will have the different degree of hydration reaction, also produce a large number of micro-pore and cause thermal damage to various materials in the concrete, which will affect the bonding performance between GFRP bars and concrete (Han et al, 2019;Bi et al, 2021;Zou et al, 2021). The porosity of concrete directly affects the bond area between GFRP bars and steam cured concrete, which leads to the decrease of bond performance.…”

Section: Introductionmentioning

confidence: 99%

The effect of pore characteristics on the bonding properties of steam-cured concrete and GFRP bars

et al. 2023

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Steam cured concrete prefabricated components has the advantages of short construction period, less environmental pollution, convenient construction and low cost, and is widely used in high-speed railway projects. However, the changes of later strength, capillary water absorption and pore distribution led to the reduction of durability of steam-curing concrete and accelerated the damage speed of GFRP bars and bond performance between concrete and GFRP bars. In this study, the method of steam curing is adopted to simulate the damage of components caused by actual steam curing environment. The influence of pore characteristics on the bonding properties of steam cured concrete and GFRP steel bar is analyzed from both micro and macro perspectives. Analysis method combining pore characteristics with bonding strength. The test results showed that the hydration products of concrete were unaffected, but the density of the hydration products changed due to the steam curing. The porosity of the steam-cured concrete was much higher than that of the standard-cured concrete. The number of gel pores smaller than 20 nm accounted for 12.27% of the total number of pores on average, which was about twice the proportion of the gel pores of this size in the standard-cured concrete. The proportion of harmful voids with pore size of 50–200 nm and greater than 200 nm is higher than that of standard curing concrete. The bond strength of the steam-cured concrete and GFRP bars was 30% lower than that of the standard-cured concrete. With the change of the thickness of the concrete cover and the diameter of GFRP bars, the bond strength changed significantly. Based on the analysis of the test data, a predictive model of the bond strength deterioration for the steam-cured concrete and GFRP bars was established. The model fully accounted for influence factors such as the porosity, diameter, anchor length, and concrete strength.

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