Properties of cement grout doped with xanthan gum and welan gum at high hydration temperatures

The effects of xanthan gum (XG) and welan gum (WG) on the properties of cement grout at various hydration temperatures were studied. The laboratory tests including bleeding, rheology, and strength were carried out, and the microscopic analysis was carried out to reveal the mechanism. The results showed that the gums could thicken the cement grout. The apparent viscosity of cement grout containing XG increased with the rise in temperature, while the WG first increased and then decreased. XG could significantly decrease the bleeding rate, but this effect weakened in the high temperatures. WG first decreased then decreased the bleeding rate, and this variation was closely affected by the temperature. The addition of gums could decrease the strength and density of hardened grout. XG could diminish the differences between the upper and lower part of hardened grout, indicating the XG could resist the deterioration of high temperatures, while the XG enhanced the degraded effect. The addition of gums could cover the cement particles to inhibit the cement hydration but had a slight impact on the mineral phase composition. The Ettingite was not found because it decomposed in the high temperature. Meanwhile, the C-A-S-H gels were observed in the XRD patterns and SEM images, indicating that it was enhanced under high-temperature conditions.