Thermal and strength properties of lightweight concretes with the addition of aerogel particles

Abstract

The aim of this work was to examine the influence of the addition of aerogel particles on the properties of cement composites manufactured using fly ash aggregate. The composites were tested at three different concentrations of water saturation of the coarse aggregate. Moreover, two methods of aerogel particle application were usedplasticising the mix with superplasticiser and aerating with an air-entraining admixture. An assessment of the thermal properties was made during the first 28 d of curing of the composites and compressive strength tests were conducted after 7 and 28 d. For pore structure characterisation, mercury pore structure analysis was carried out on the pure aerogel, the cement composites and the composites with the addition of granulate. The data obtained indicate that adding aerogel particles to concrete composites is an appropriate method of improving thermal parameters: thermal conductivity coefficients were two times smaller compared with control samples without aerogel and, simultaneously, the volumetric specific heat was comparable to that of the control samples. However, the addition of aerogel resulted in a reduction in compressive strength to approximately only 30% of that of the control samples. Notation c v volumetric specific heat D pore diameter f cm compressive strength k f coefficient dependent on the transition pressure L pore size P pressure P t transition pressure V normalised mercury volume γ surface tension θ contact angle λ thermal conductivity coefficient 567 Advances in Cement Research Volume 28 Issue 9 Thermal and strength properties of lightweight concretes with the addition of aerogel particles Strzałkowski and Garbaliń ska

Effect of various curing methods and addition of silica aerogel on mortar properties

“…However, an exact opposite pore structure is required for high mechanical strength [1,4,5]. Similarly, when the effect of aerogel contribution on the concrete pore structure was investigated, it was found that the aerogel used at 20 % by volume can increase the total porosity value by 8.63 % through an additional pore volume created, especially at the porosity range of 10 -30 nm [12]. Studies that examine the change of pore structure in aerogelincorporated mortars under durability conditions are currently quite limited.…”

Thermal and Strength Properties of Lightweight Concretes with Variable Porosity Structures

“…Noticeably, the values recorded for the concretes with aerogel are higher than those for the initial tests presented by Strzałkowski and Garbalińska, 2016. In the process of mixing, the aerogel particles were partially squeezed and fragmented, which is reflected in the results. In the initial tests, however, mixes of a maximum of 2 liters were prepared and the concrete was stirred manually, not mechanically.…”

Evaluation of dampness-induced strength reduction of calcium silicate blocks

“…It is common knowledge that the properties of given materials are determined by their internal structure and arrangement of pores, particularly those which can be filled with water in the liquid phase, cf. [7][8][9][10]. Table 2 lists the values of apparent density and moisture content by weight and volume specified for individual water-saturated blocks.…”