Contribution to the Design of Hydraulic Lime-Based Grouts for Masonry Consolidation

Henriques

Cidade

2019

Fluids

This review provides an overview of the recent progress in the field of the rheology of grouts for historic masonry consolidation. During the last two decades, significant research has been devoted on the grouting technique for stone masonry consolidation but most results are scattered by scientific papers, congress communications, and thesis. This paper compiles and briefly demonstrates the effect of several intrinsic and extrinsic parameters, such as admixtures, additions, pressure, temperature, and measuring instrumentation, on the rheological performance of natural hydraulic lime-based grouts.

Section: Fly Ashsupporting

confidence: 88%

“…The injection grouts are often referred to as non-Newtonian, thixotropic, and in possession of a yield stress [14,[34][35][36]. This non-Newtonian behavior can be attributed to mechanisms in which the shear stress orients the suspended binder particles in opposition to the randomizing effects of Brownian motion [14,[37][38][39].…”

Section: Rheological Modelsmentioning

confidence: 99%

Rheology of Natural Hydraulic Lime Grouts for Conservation of Stone Masonry—Influence of Compositional and Processing Parameters

Henriques

Cidade

2019

Fluids

“…From Table 9 it is clear that the NS dosage is the factor with the greatest influence on viscosity values. As reported elsewhere [15,30], the addition of particles with a high specific surface promotes a great influence in the rheological parameters, namely in the plastic viscosity. The introduction of small-sized particles as NS and SF is the source of additional surface area, resulting in an increase of contact forces among fine particles, leading to easier coagulation due to interparticle interactions (Van-der-Waal's interactions).…”

Section: Rheological Measurementsmentioning

confidence: 53%

“…However, these simple formulations are unable to perform efficient consolidation, therefore requiring the use of additional products. According to other studies [10][11][12][13][14][15][16], some grout properties can be improved with the use of additives in the grout composition, in particular pozzolans that can be added to the base grout. Even though the influence of incorporation of pozzolans as supplementary materials in grouts production has been investigated widely in the last two decades [10,[15][16][17][18][19], the influence of materials with a nano-size in grouts for old stone masonry consolidation has not been investigated to a great extent.…”

Section: Introductionmentioning

confidence: 99%

Preliminary Investigation of the Mechanical and Physical Properties of Natural Hydraulic Lime Grouts with Nano-Silica

Cardoso

2021

CivilEng

Self Cite

Natural hydraulic lime-based grouts are often used in the structural consolidation of old stone masonry walls, mainly to re-establish the monolithic behaviour of masonry constructions. To ensure an adequate grouting operation, it is essential to have good fresh and hardened grout properties. The motivation of the present study was to examine the fresh and hardened properties of natural hydraulic lime grouts with nano-silica (NS) and silica fume (SF). The contribution of these materials and the dosage of a high range water reducer admixture (HRWR) were investigated on the rheological properties, water capillarity, open porosity and mechanical strength of injection grouts. The effects on rheology were analysed through plastic viscosity and yield stress. The results indicated that, even for reduced NS content, an increase in plastic viscosity and yield stress occurred, which required a higher HRWR content in order to not compromise the grout’s rheological performance. The results also showed that, when NS and SF were combined, a beneficial joint effect occurred, resulting in a substantial and positive change on the mechanical strength and microstructure of the hardened injection grouts. Taguchi’s method was used to optimize the grout’s formulation and to fulfil the required performance concerning the fresh and hardened state.

“…Rheological measurements allow the evaluation of the effects of different grout composition on the fresh behaviour and a proper characterization through rheological models [8]. Based on previous works [6,9] it is accepted that fresh behaviour of natural hydraulic lime grouts can be represented using the Bingham model. Therefore, if the fresh grout is assimilated to a Bingham fluid two independent parameters are needed to describe the rheological behaviour, such as yield stress and plastic viscosity.…”

Section: Introductionmentioning

confidence: 99%

Rheology of Grouts for Masonry Injection

Henriques

2014

KEM

Self Cite

Grout injection technique applied in a multiple leaf masonry walls aims at increasing the compactness of the masonry and, therefore, improving their monolithic behaviour by bonding the separated segments together without compromising the architectural value of the masonry building. The success of the injection grouts depends mainly on their rheological properties. This means that the flow properties of fresh grouts are as important as their properties in the hardened state, since they govern the ability of the grout to flow and fill the voids within masonry. In practice, the variability of voids within masonry requires ability to fine tune the rheological properties of the grout, in order to optimal fill all voids with grout. So, models were developed with the main purpose of predict and control the rheological properties of grouts just performing simple flow tests traditionally used in the field. It is well known that flow tests commonly performed (such as Marsh cone and slump test), which try to describe the workability of cementitious materials, only give a qualitative result that can not be expressed in physical rheological units. However, the proposed models allow calculating a physical parameter (e.g. viscosity) instead of an empirical one (e.g. fluidity). This research shows the effect of grout design variables on the properties of natural hydraulic lime grouts based on the correlation between rheometry measurements and simple flow tests. Furthermore, the proposed models can be very useful to smooth the grout design methodology, since these models enable the prediction of rheological properties of the grout without the need for expensive and complex equipment, such as rheometers or viscometers.