Page 7 - Open access sep 2020

TECHNICAL PAPER

Table 1: Design strategies in research for 3D printable concrete mix
SL. UNIVERSITY/ DESIGNING OF 3D PRINTABLE MIX REFERENCES
NO. INSTITUTE
1 ETH Zurich 1. Developed ‘sleeping’ mortar, which is retarded at the time of mixing and accelerated at the print head for Wangler et al. (2019)
fast setting Lloret et al. (2017)
2. Developed a special self-compacting concrete for mesh mould approach, which should not flow out. Hack et al. (2017)
3. The combined effect of aggregate grading and yield stress on extrudability and mix design
2 TU Eindhoven 1. Zero to no slump mix is prepared using OPC (CEM I 52.5 R) with limestone filler; rheology modifying Wolfs et al. (2018a;
admixture is used. b, 2019a)
2. Aggregates (siliceous) of size less than 1 mm and polypropylene fibers are used.
3 TU Dresden 1. Strain hardening cement-based composite for 3D printing. The printed mix showed better strain Ogura et al. (2018)
hardening behaviour compared to cast specimens. Markin et al. (2019)
2. Foam concrete for 3D printing is developed with a density range of 970 to 1500 kg/m3.
4 University A cement from lunar anorthite and glass is manufactured by sintering. This cement is created to construct Zhang and Khoshnevis
of South habitations in the moon using local soil. The major challenge on the moon would be the production of the (2017)
California, concrete because of less gravity. Three methods for production are discussed: wet-mix method, Dry-mix Khoshnevis et al.
USA method, and waterless sulphur/regolith (heterogeneous deposits on a rock found in the earth, mars, moon (2005)
etc.) mix method. The possibility of using sulphur concrete in the lunar mission is highlighted.
5 Arizona State The cementitious binder is developed considering the pre-print and post-print parameters such as
University rheological properties, steady-state extrudability pressure, stability, mechanical properties and dimensional Neithalath (2019)
accuracy of print, and the process is termed as performance-based mix design
6 Loughborough 1. A high-performance mix with compressive strength of 100-110 MPa is printed by Loughborough Lim et al. (2011)
University University, UK, to compensate for the strength loss at interlayer bonds. Le et al. (2012a)
2. The developed mix had 3:2 sand to binder ratio, 0.26 water/cement ratio, and 20% fly ash and 10%
silica fume and polypropylene fibers. The reported build-up is up to 61 layers in one session with a
compressive strength of 110 MPa at 28 days.
7 IIT Madras 1. A yield stress-based mixture design approach for 3D printed concrete; Nanoclay, VMA and silica fume Rahul et al. (2019a)
used as special additives Rahul et al. (2019b)
2. Mechanical behaviour of 3D printed concrete Rahul et al. (2020a)
3. Mitigation of liquid phase separation during the extrusion of cement-based materials Rahul et al. (2020b)
4. Development of mixtures with lightweight coarse aggregates
8 TU Munich 1. Lightweight concrete of density 995 kg/m is developed with a 1:1 ratio by volume of portland-limestone Weger et al. (2018)
3
cement and untreated softwood chips. Henke et al. (2017)
2. Air-entraining, accelerating, and stabilizing admixtures are added along with expanded glass as Henke et al. (2016)
lightweight aggregate.
9 Ghent 1. Sustainable concrete mix for breakwater units is being developed and currently under study. Ugent (2019)
University 2. Applying topological optimization to construct a 3D printed post-tensioned girder Vantyghem et al.
(2020)
10 Swinburne Swinburne University developed geopolymer concrete for 3D printing using a powder-based 3D printer, Swinburne (2018)
University of using slag and fly ash-slag combination, along with different types of alkaline solutions. The studies Xia et al. (2019)
Technology included the effect of powder deposit ability, powder wettability, the accuracy of linear dimensioning, and Nematollahi et al.
measurement of compressive strength. (2017)
11 Stellenbosch The use of nanomaterials like Silicon carbide nanoparticles enhances thixotropy. The infusion of Heever (2018)
University nanoparticles in high-performance concrete improves mechanical performance and interlayer bonding. Bester (2018)
12 Nanyang 1. The mix is developed by alternative binders (geopolymer concrete), and nano-clay as additive. Panda et al. (2019)
Technological 2. The mix design approach is developed to form a correlation between cementitious material components Panda et al. (2018)
University and rheological properties to form an optimized material composition. Mathematical models are Liu et al. (2019)
experimentally validated based on ANOVA analysis and optimum SCMs mix designs are developed. Weng et al. (2019b)
3. Study to increase the sustainability and cost-effectiveness by use of environment-friendly magnesium
potassium phosphate cement (MKPC) with fly ash replacement from 0 to 60% and silica fume
replacement of 10% is done.
13 Northwestern Martian concrete or Marscrete is made from a combination of sulphur and a replica of martial soil (soil found Benavides (2019)
University on earth with similar Martian soil properties).
14 Université 1. CSA admixture in 3DCP can change the rheological behaviour. An optimum mix of OPC: CSA of 93:7 is Khalil et al. (2017)
Lille, IMT prepared.
Lille-Douai 2. The mix can sustain printing till 25 layers as reported against the 10 layers of 100% OPC mix. The total
heat evolution of the OPC-CSA mix is like the OPC mix but in the initial periods the thermal signature
of OPC-CSA mix is like pure CSA, hence, allowing early hardening. The setting time is also less for the
OPC-CSA mix.

THE INDIAN CONCRETE JOURNAL | SEPTEMBER 2020 11