Physico- mechanical and micostructural effects of water/cement ratio on the mortars upon heating

Messaoudene, Ibrahim; Ezziane, Mohammed; Lahouassa, Ammar; Kaaloul, Souhil; Molez, Laurent

Journal of Materials and Engineering Structures
Volume 8, Numéro 2, Pages 279-286
2021-06-30

Physico- Mechanical And Micostructural Effects Of Water/cement Ratio On The Mortars Upon Heating

Authors : Messaoudene Ibrahim . Ezziane Mohammed . Lahouassa Ammar . Kaaloul Souhil . Molez Laurent .

Abstract

This experimental work studies the effect of the W/C ratio on the mechanical properties of the mortars subjected to the high temperatures. Fours mortars were made according to EN196-1standard. A typical mortar mix with W/C = 0.5 and three others mortars with W/C= 0.3; W/C= 0.4 and W/C= 0.6. They were exposed to a slow heating in a muffle furnace until the target temperature (100, 200,300,400,500,600,700 and 800°C) with a step of 2°C.min-1 and cooling to room temperature took place in the closed and disconnected oven (approximately -0.3°C/min). After thermal stress, mortars with high W/C ratio (0.5 and 0.6) show a decrease in compressive strength much greater than those with low W/C ratio (0.3 and 0.4). The flexural strength of different mortars has a similar shape to those of the compressive strength. The weight loss and water absorption results are consistent with the mechanical behavior. The SEM tests were carried out on samples of unheated control cement and cements heated to 400°, 500° and 800°C. The SEM observations explain the mechanical strength. At upper temperature (800°C), the material is too much damaged and measurements become difficult.