Mortar

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

Application of artificial neural networks for the prediction of the compressive strength of cement-based mortars

Abstract: Despite the extensive use of mortar materials in constructions over the last decades, there is not yet a robust quantitative method, available in the literature, which can reliably predict mortar strength based on its mix components. This limitation is due to the highly nonlinear relation between the mortar\'s compressive strength and the mixed components. In this paper, the application of artificial neural networks for predicting the compressive strength of mortars has been investigated. Specifically, surrogate models (such as artificial neural network models) have been used for the prediction of the compressive strength of mortars (based on experimental data available in the literature). Furthermore, compressive strength maps are presented for the first time, aiming to facilitate mortar mix design. The comparison of the derived results with the experimental findings demonstrates the ability of artificial neural networks to approximate the compressive strength of mortars in a reliable and robust manner.

Electrical-resistance-based Sensing of Impact Damage in Carbon Fiber Reinforced Cement-based Materials:

Abstract: Damage monitoring of the civil infrastructure is critically needed. This article provides the first report of impact damage self-sensing in cement-based materials. Cement mortar reinforced with short (57 mm) carbon fiber and in bulk or coating (510 mm thick) form is effective for sensing its own impact damage through DC/AC electrical resistance measurement, provided that the region of resistance measurement contains the point of impact. The mortar resistivity needs to be 10 4 10 5 X cm, as provided by pitch-based fiber (15mm diameter, unsized) at 0.5% or 1.0% by mass of cement, or type A PAN-based fiber (7mm diameter, desized) at 0.5%. Due to the low mortar resistivity of 10 3 X cm, pitch-based fiber at 1.5% and type B PAN-based fiber (7mm diameter, unsized) at 0.5% are less effective. Without fiber, there is no sensing ability. The surface resistance of the surface receiving the impact is an effective indicator of the damage, even for minor damage without cracking, inflicted by impact at 880 J. The oblique or longitudinal volume resistance is much less effective. The surface resistance increases abruptly upon impact, but it decreases abruptly upon impact after 540 impacts (number decreasing with increasing impact energy) have been inflicted. Key Word: cement, concrete, carbon fiber, sensing, damage, impact, electrical resistance, electrical resistivity.

Analysis of the drying shrinkage behaviour of concrete using a micromechanical model based on the micropore structure of concrete

Abstract: A micromechanical model for moisture diffusion within concrete and the associated shrinkage of concrete is presented in this paper. The model is based on the micropore structure of the concrete and the thermodynamic behaviour of the water in the pores. The drying shrinkage behaviour, both time-dependent moisture loss and volumetric change, of mortar and concrete specimens is analysed under various conditions. The suitability and applicability ofthe proposed model are discussed on the basis ofthe results.