Effect of water entrainment by pre-soaked biochar particles on strength and permeability of cement mortar

•Internal curing in mortar by water entrainment in pores of biochar is proposed.•Moisture retention and hydration degree are increased due to addition of pre-soaked biochar.•Increase in mechanical strength is observed in pre-soaked biochar mortar under wet curing and dry curing conditions.•Improved...

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Vydáno v:Construction & building materials Ročník 159; s. 107 - 125
Hlavní autoři: Gupta, Souradeep, Kua, Harn Wei
Médium: Journal Article
Jazyk:angličtina
Vydáno: Elsevier Ltd 20.01.2018
Elsevier B.V
Témata:
Biochar
Building materials
Cement additives
Internal curing
Methods
Mortar
Mortar mixing
Permeability
Solid wastes
Strength
Waste management
Singapore
Mortar
Permeability
Biochar
Internal curing
Strength
ISSN:0950-0618, 1879-0526
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Shrnutí:•Internal curing in mortar by water entrainment in pores of biochar is proposed.•Moisture retention and hydration degree are increased due to addition of pre-soaked biochar.•Increase in mechanical strength is observed in pre-soaked biochar mortar under wet curing and dry curing conditions.•Improved water tightness is achieved under wet and dry curing due to addition of dry and pre-soaked biochar. Water retention by biochar makes it a potential material for soil enhancement. However, its application as an internal curing agent in cementitous matrix is relatively unexplored. This study explores addition of pre-soaked biochar on strength and permeability of cement mortar, subject to moist curing and air curing respectively. Biochar was prepared from mixed wood saw dust at pyrolysis temperature of 300 °C (BC 300) and 500 °C (BC 500) respectively. Biochar particles were saturated with water prior to addition in mortar mix at 2 wt% of cement. Experimental results show that mortar with pre-soaked BC 300 and BC 500 offer 40–50% higher compressive strength at 28-day compared to plain mortar, especially under air curing condition. Similar trend is observed for flexural and split-tensile strength. It is linked to initially low water-cement ratio of mixes with pre-soaked biochar and internal availability of moisture from pores of biochar under external dry condition. Water accessible porosity was reduced by 18–20% due to addition of pre-soaked biochar, that resulted in reduction of sorptivity and depth of water penetration by 55–60%. Overall, significant improvement in mechanical and permeability properties were observed when pre-soaked biochar is used compared to addition of dry biochar in mortar, especially in absence of external moist curing. The internal curing efficiency of pre-soaked biochar on mortar was found to be higher compared to other mixes, which suggests that it can be a potential curing material for cement mortar. Using biochar as additive in cement mortar also ensures higher waste recycling and carbon sequestration in civil infrastructure while improving strength and durability performance.
ISSN:0950-0618
1879-0526
DOI:10.1016/j.conbuildmat.2017.10.095