Mortar

About: Mortar is a research topic. Over the lifetime, 25024 publications have been published within this topic receiving 218739 citations.

Concrete mix design based on water film thickness and paste film thickness

Abstract: In previous studies on the mortar portion of concrete, it has been found that the water film thickness (WFT) and paste film thickness (PFT) have major effects on the performance of mortar. The present study aims to extend the concepts of WFT and PFT to concrete. For this aim, a number of concrete mixes with various paste volumes, water/cement ratios and fine to total aggregate ratios were produced for slump, flow, strength and packing density measurements, and from the results, the combined effects of WFT and PFT on the deformability, flowability and strength of concrete were studied. It was found that whilst the WFT is the key factor governing the above properties of concrete, the PFT also has significant effects and thus is an important factor to be considered in concrete mix design. Lastly, based on the test results, two design charts for concrete mix design were produced.

Mesoscopic Simulation of Failure of Mortar and Concrete by 3D RBSM

Abstract: Concrete is a heterogeneous material consisting of mortar and aggregate at the meso scale. Evaluation of the fracture process at this scale is useful to clarify the material characteristic of concrete. The authors have conducted meso scale analysis of concrete over a past few years by Rigid Body Spring Model (RBSM). In this study, three-dimensional analyses of mortar and concrete are carried out, which is necessary for the quantitative evaluation of concrete behavior especially in compression. Constitutive models at the meso scale are developed for the 3D RBSM analysis. Failure behaviors and strengths in compression and tension of mortar and concrete are predicted well by the analysis. In biaxial compression test of concrete, crack in normal direction to plane of specimen is simulated that cannot be presented by two-dimensional analysis.

Enhancing the performance of pre-cast concrete blocks by incorporating waste glass - : ASR consideration

Abstract: There is a growing interest of using recycled crushed glass (RCG) as an aggregate in construction materials especially for non-structural applications. Although the recycled crushed glass is able to reduce the water absorption and drying shrinkage in concrete products due to its near to zero water absorption characteristics, the potential detrimental effect of using glass due to alkali–silica reaction (ASR) in cementitious materials is a real concern. The extent of ASR and its effect on concrete paving blocks produced with partial replacement of natural aggregates by crushed glass cullet are investigated in this study. This study is comprised of two parts. The first part quantified the extent of the ASR expansion and determined the adequate amount of mineral admixtures that was needed to reduce the ASR expansion for concrete paving blocks prepared with different recycled crushed glass contents using an accelerated mortar bar test in accordance with ASTM C 1260 (80 °C, 1 N NaOH solution). In the second part, concrete paving blocks were produced using the optimal mix proportion derived in the first part of this study and the corresponding mechanical properties were determined. It was found from the mortar bar test that the incorporation of 25% or less RCG induced negligible ASR expansion after a testing period of 28 days. For mixes with a glass content of higher than 25%, the incorporation of mineral admixtures such as pulverized fuel ash and metakaolin was able to suppress the ASR expansion within the stipulated limit but the results need to be confirmed by other test methods such as the concrete prism test. The study concluded that the optimal mix formulation for utilizing crushed waste glass in concrete paving blocks should contain at least 10% PFA by weight of the total aggregates used.