Elastic modulus changes in cementitious materials submitted to thermal treatments up to 1000°C

Abstract

Three categories of cementitious materials (Portland cement pastes, siliceous and calcareous sand mortars, and microconcretes with siliceous sand and silica fume) were subjected to cumulative thermal treatments at temperatures (T) up to 1000°C. Changes in room-temperature elastic modulus E*(T) of heat treated materials were followed by a non-destructive ultrasonic technique at 10 MHz. Each category exhibits specific changes in E*(T)/E*0 plotted against T, where E*0 was the value before heat treatment, irrespective of the water:binder ratio.

The effect of undrained heating on a fluid-saturated hardened cement paste

“…Furthermore, in the absence of any information on the value of φ α , we assume that give a constant value for the thermal expansion coefficient of the cement pore fluid which is obtained as an average value of the heating and cooling phases. A more detailed calculation can be done using equation (33) and the data of the performed undrained heating test. By doing so, the value of the thermal expansion coefficient of the cement pore fluid can be calculated for each data point during the test.…”

Estimation of Porosity and Pore Distribution in Hydrated Portland Cement at Elevated Temperatures using Synchrotron Micro Tomography

“…1 shows an exothermic reaction taking place at 80°C labeled region 'a' in Fig. 1, which is due to the evaporation of free and absorbed water (Masse et al 2002). Endothermic peak is observed between 400°C and 430°C which is primarily due to the dehydration of calcium hydroxide and partially due to CSH.…”

Effect of high temperature on mechanical and acoustic emission properties of calcareous-aggregate concrete

“…(2)). When the temperature was ranged from 600°C to 800°C, the cracks expansion continued and the decrease of compressive strength was associated with the decarbonation of calcium carbonate of the calcareous aggregate [8,9]. Calcium carbonate decomposed into calcium oxide or ''lime'' (the product of the decarbonation of calcium carbonate) and carbon dioxide at the temperature above 700°C (as shown by Eq.…”

“…when it rises to 600°C, the hydrated calcium silicate (C-S-H) which plays an important role in the hardening property and cement strength begins to crumble [4][5][6][7]. At 600-800°C, the calcium carbonate in calcareous aggregate undergoes decarburization reaction [8][9].…”

“…The compressive strength [2,3,6,10,11], tensile strength [2,11] as well as the elastic modulus [9][10][11]of concrete can be damaged under high temperature. The mechanical response of concrete to temperature is related to its constituents and mix proportions (such as aggregate type, water-cement ratio, fly ash and plasticizer).…”