The impact of modified cement with a special additive on construction mortar deformations

National University of Architecture and Construction of Armenia, Yerevan, Republic of Armenia

^* Corresponding author: meimaryan@mail.ru

Abstract

The study is devoted to the modification of 42.5 class ordinary Portland cement with a 10% special expanding additive (cement powder and gypsum in a 40:60 percentage ratio), and the impact of this cement on mortar is determined. Using modified cement and multi-fraction quartz sand in a ratio of 1:3, prism-shaped samples with a size of 4x4x16 cm were fabricated, and left in a water bath for 24±2 hours after formation. After one day of curing, the samples were demolded, their linear dimensional change was verified using an indicator, and they were then submerged in water. After three, seven, and 28 days of curing, the samples’ changes in linear dimensions were examined again using an indicator. It has been revealed that introducing a 10% specially developed expansion additive to the composition of ordinary Portland cement also contributes to the maximum expansion of the construction mortar at 3–7 days of hardening. The expansion percentage of the 28-day curing time is very little different from the 7-day indicator. Considering the data on the linear dimensional change of the test samples, we can conclude that the modification of cement with the synthesized additive allows the production of non-shrinkable, expansive construction mortars and concretes, which are currently being studied.