Workability Of Cement Mortar Research Articles

Compressive Strength and Workability of Cement Mortar Containing Recycled Asphalt Pavement

This article presents the compressive strength and workability of cement mortar (CM) containing recycled asphalt pavement (RAP) as fine aggregate replacement. The effect of the RAP replacement, water to cement ratio, curing time, and aggregate water absorption on compressive strength and flow workability are reported. The results show that the mixing water and mixing time play a significant role in the compressive strength and unit weight of CM containing RAP. The RAP has a higher water absorption and slower rate of water absorption than those of sand. The flow workability of CM increases with RAP replacement due to the unabsorbed water at the initial mixing stage. The main negative factors that affected the compressive strength of CM containing RAP as a fine aggregate replacement are revealed. The unabsorbed water at the initial state of mixing before hardening causes increased flow workability and decreased compressive strength. The findings from this research will promote the mix design approach of CM containing RAP as a fine aggregate replacement, for moving toward increased applications of recycled materials in a sustainable manner in civil engineering construction.

Fine aggregate substitution with acidified granular activated carbon influences fresh-state and mechanical properties of ordinary Portland cement mortars

Abstract The compressive strength and selected fresh-state responses to incorporating acid-modified granular activated carbon (GAC) in cement mortars, were compared to physical cement behaviors associated with the incorporation of otherwise unmodified GAC and a commercial polycarboxylate superplasticizer. Specific surface area of unmodified and acidified GAC, porosity, pH at charge neutrality (pHPZC), and surface-associated functional groups were compared. Fresh- and hardened-state responses were observed, including slump, setting time, zeta potential, and compressive strength. Results suggest that substituting 1% of the fine aggregate mass with GAC particles that had been pre-treated in nitric acid, can improve compressive strength and workability of cement mortar.

Effect of nano-alumina on workability, compressive strength and residual strength at elevated temperature of Cement Mortar

This experimental investigation aims at studying the effects of nano-alumina (NA) on mechanical properties of cement mortar when used as cement replacement in mortar mix. For this purpose, 1%, 3% and 5% of the NA was introduced into the mix to observe the variation of fresh and hardened properties of mortar, change in workability, the resulting effects on compressive strength at 7 and 28 days aid and fire resistance were observed. The results obtained were compared with the controlled specimen. It has been observed from the results that the addition of nano-alumina indicated moderate increase in the compressive strength and substantial increase in fire resistance properties of the cement mortar however, it was observed a decrease in workability of cement mortar.

Properties of Ferrocement Slabs Containing Sawdust

This research included the study of influence of sawdust addition on the properties of mortar and ferrocement slabs and study the influence of treatment sawdust on the static and dynamic properties of the Sawdust Ferrocement Slabs (SFS). In the present work, addition a different sawdust percentage ranged between (10% to 50%) of the volume of fine aggregate to cement mortar and superplasticizer was used to increase compressive strength and workability of cement mortar. The tests include, samples of cubes and prisms were tested for compressive strength and modulus of rupture and calculated the thermal conductivity for Sawdust Cement Mortar (SCM). The results show a significant improvement in the properties of cement mortar in terms of thermal insulation, the values of thermal conductivity ranged between (0.54 to 0.31) W/(m.K) ) to the ratio mixes respectively. While for the ferrocement mix without any sawdust ratio up to 0.65 W/(m.K) and this mean an improvement in the performance of mixtures of thermal insulation by 17% to 52%. The best sawdust ratio for the compressive strength is 30% where the value of thermal conductivity then is 0.38 W/(m.K) and the value of compressive strength of (29 Mpa). Also, Sawdust Ferrocement Slabs (SFS) (treated and untreated) were cast and tested under static and dynamic loads effect. The results show a good improvement in the mechanical properties of (SFS) under these loads.

Influence of environmental temperature and moisture content of aggregates on the workability of cement mortar

In this experimental work, which is aimed at a subsequent industrial application, the results of a study of the effects of environmental temperatures on aggregate’s properties and on the resulting mortar workability are presented. For this work, several physical properties of fine aggregates (sand of 5 and 2 mm) were defined, in order to establish the influence of temperature on their performance and on the resulting mortar’s workability. In this study, three climatic conditions were used: reference, hot weather and cold weather conditions, both in terms of temperature and relative humidity. The results show that mortar workability is a function of the temperature of the aggregates and of their physical properties, such as absorption and friction; in general, the best results are attained under the reference conditions (20 °C). These results may be useful for the optimization tools development in ready-mix concrete production.

Reuse of sewage sludge ashes (SSA) in cement mixtures: the effect of SSA on the workability of cement mortars

The influence of sewage sludge ash (SSA) on workability of cement mortars has been studied. The irregular morphology of SSA particles produced a decrease of mortar workability. A nonlinear reduction of workability in mortars containing SSA was observed, but when SSA content in mortars was increased the workability reduction was less significant. A superplasticizer is used in order to compensate the decrease of workability produced by SSA. When SSA sized fractions were used, only significant differences in workability for mortars prepared with high water volumes or with the presence of superplasticizer were observed.