Lime Concrete

A composite mixture of limestone as the binding agent, sand for fine aggregate, and gravel for coarse aggregate in the right amounts is called lime concrete. The ratio of lime to sand and coarse aggregate in a lime concrete mix can range from 1:2:3 to 1:2:4, depending on the kind of construction.
Prior to the widespread use of cement as a binding element, lime concrete was widely used in construction. These days, vapor-permeable insulating bases with lime concrete laid on top of them are also utilized as capillary breaks.

There are two categories for limes:

1. Class A: Magnificent hydraulic lime for building applications.
2. Class B: Semi-hydraulic lime for Lime concrete

How Much should be used in Lime Concrete

1. The volume ratio of aggregate to lime mortar must be followed.
2. To prepare lime, one should typically combine 40 parts of a specific mix of lime mortar with 100 parts of graded stone aggregate, gravel, or brick aggregate, all of which should be 40 mm nominal in size.

Lime concrete mixing

A mechanical mixer is used to mix lime concrete. In certain situations, mixing by hand is permitted. Before mixing, stone aggregate or gravel needs to be thoroughly cleaned with water to get rid of any dirt, dust, or other foreign objects, and brick aggregate needs to be well soaked in water for at least 24 hours.

1. Mixing by machine

1. The mixer’s drum must be rotated while the measured amount of coarse aggregate and wet ground mortar are added.
2. The amount of materials placed inside the drum cannot be more than the mixer’s rated capacity.
3. After adding water gradually until the necessary amount, a batch must be wet mixed in the drum for at least two minutes to produce properly coloured, evenly spread concrete with the right consistency.
4. The lime concrete’s consistency ought to be such that the mortar and coarse aggregate don’t tend to separate.
5. Concrete should be removed from the mixer if segregation occurs after unloading.
6. Before the components for the next batch are placed into the drum, the full batch of concrete must be released.
7. The mixer must be cleaned by rotating the drum with lots of water each time before work is suspended.

2. Using a hand mixer

1. If hand mixing is allowed, it must be done on a masonry platform that is large enough to provide for enough space for mixing and is clean and waterproof.
2. The aggregate must be covered with the designated wet lime mortar. Turning must be done repeatedly while adding the required amount of water until the desired consistency is achieved in a homogenous mixture.
3. The lime concrete must have a consistency that prevents the mortar from tending to separate from the coarse aggregate.

Positioning and Density

1. While the lime concrete is still new, it must be put in layers.
2. Before adding the next layer of lime concrete, the previous layer must be completely rammed and solidified.
3. Each layer’s combined thickness cannot be more than 15 cm. If required, joints should be spaced out across several layers unless otherwise noted.
4. Heavy iron rammers weighing between 4.5 and 5.5 kg are required for ramming, and their maximum surface area is 300 square centimetres.
5. Ramming must be carried out until the laid lime concrete’s surface is entirely covered in a layer of mortar.
6. Before work is stopped on a given day, all concrete that has been laid must be completely cemented.
7. Adequate coverings must be used to shield freshly placed concrete from the elements.

Lime concrete curing

1. The concrete must be kept damp for a minimum of seven days using moist gunny bags, sand, or any other technique once it has started to solidify, which is around twenty-four hours after it is placed and compacted.

Properties of Lime Concrete

1. Lime concrete has the appropriate fluidity and is well workable.
2. Because of its certain degree of waterproofing, it keeps subsurface moisture from rising.
3. It is resistant to weathering.
4. Bases made of lime concrete can support enough weight.
5. The setting need further time.
6. At the beginning of the setting process, it achieves noticeably less compressive strength.
7. Compared to regular Portland cement, lime concrete is more environmentally friendly since it uses less energy to produce lime and produces less carbon dioxide during the carbonation process.