Influence of cement type and water content on the fresh state properties of ready mix mortar

Abstract

The main characteristic of ready mix mortar is to remain workable for up to 72hours after mixing. This greater duration of workability is obtained by use of hydration stabilizing admixtures and air-entrained admixtures. Thus, the behavior of this mortar depends on the compatibility between Portland cement and these two admixtures. Within this context, the objective of this article is to evaluate the influence of Portland cement type and water content on the properties of ready mix mortars in fresh state. Three types of Portland cement and four water/dry material ratios were evaluated. The produced mortars were analyzed with respect to their properties in fresh state: consistency index, specific gravity, air entrained content and rheological behavior by squeeze-flow. The properties were determined for three storage durations (0, 24 and 48 hours). The results show that both types of cement (mainly, the rheological behavior) and water content (mainly, the air entrained content, consistency and rheological behavior) influenced the ready mix mortar properties. Therefore, these two parameters must be evaluated for mortar dosages in order to obtain the required properties in fresh state.

Using ready-mixed mortars in concrete block structural masonry

“…The workability loss (i.e. increases in the consistency and plasticity values) over time observed for the 6 MPa mortar is in line with the results reported by Casali et al (2018), who found reductions in the flow table test values over time for ready-mixed mortars produced with different types of Portland cement. The authors justified this behaviour by a possible start in the cement hydration reactions.…”

“…In addition, the compaction process performed during the slump test may remove part of the entrained air of the mixtures, while the Gtec test is performed in a mortar sample that is practically undisturbed, which is closer to a real condition. Casali et al (2018) also reported the limitation of some empirical tests on the evaluation of fresh state properties of mortars. The authors evaluated the influence of the cement type and storage time on the fresh properties of ready-mixed mortars.…”

“…Finally, Casali et al (2018) studied the influence of the type of cement and water content on the fresh state properties of ready-mixed rendering mortars with storage times of 0, 24 and 48 hours. The consistency index, fresh density, air content, and rheological behaviour through the squeeze-flow test were evaluated at different storage times.…”

Assessment of the Impact of Inaccuracy and Variability of Material and Selected Technological Factors on Physical and Mechanical Properties of Fresh Masonry Mortars and Plasters

“…In most of the analyzed cases, an increase in the amount of water caused a decrease in air content, while a decrease in the amount of water resulted in its increase. A similar effect was observed by Cesali et al [74]. On the basis of both research data, it could be concluded that it might be possible that it was due to differences in the volume of porous mortar occupied by water.…”

Avaliação do comportamento de revestimentos em argamassas estabilizadas submetidas a tratamento superficial com aditivos cristalizantes

“…A combinação dos aditivos incorporador de ar e estabilizador de hidratação, bem como seus efeitos sobre a argamassa fresca e endurecida, vem sendo tema frequente de estudos. A aplicação e a dosagem desses aditivos, cada vez mais, requerem uma análise conjunta (ANTONIAZZI, 2019), considerando as bases químicas empregadas (CHEUNG et al, 2011;GUINDANI, 2018), o tipo de cimento (CASALI et al, 2018), a granulometria do agregado (BAUER; OLIVEIRA, 2017) e as características da mistura (ROMANO et al, 2009;FUKUI et al, 2018), entre outros fatores. Dessa forma, os estudos deveriam associar teores mais baixos de aditivos com fatores que potencializassem seus efeitos, buscando explorar sua máxima eficiência sem comprometer as propriedades da argamassa.…”