UNDER THE GUIDANCE OFPROF. ABHAI KUMAR VERMA

PREPARED BY.SAURABH SINGH

SELF HEALING CONCRETE

CONTENTSWHAT IS SELF HEALING CONCRETE.WHY WE NEED.BACTERIA AND CHEMICAL.FINDING FOR RIGHT BACTERIA.HOW DOES BIO CONCRETE WORK.SCHEMATICS OF SELF HEALING PROCESS IN

BACTERIAL CONCRETE.PERFORMANCE GRAPH.DISADVANTAGES.CONCLUSION.

WHAT IS SELF HEALING CONCRETE?

Self healing concrete are a class of material

that have the structurally incorporated ability to repair damages in presence of special bacteria and chemical caused by mechanical usage over time.

WHY WE NEED?

To preventing concrete from cracking.Protection from corrosion of steel

reinforcement.Maintaining it’s tensile strength.Reduction of future difficulties and

expensices.

An example of a severely damaged concrete support beam of a motorway

bridge

BACTERIA AND CHEMICAL

BACTERIA CHEMICAL

usually the bacilus alkalinitrulicus an alkali resistant soil bacterium is added and some times psychrophilic bacteria also added.

three different organic compounds peptone,calcium lactate and calcium glutamate.

FINDING FOR RIGHT BACTERIA

The starting point of research was to find

bacteria capable of surviving in extreme alkali environment because cement and water have ph value up to 13 when mixed together which is hostile environment for bacteria. so the bacteria can found from natural environment such as alkali lake of Russia,carbonate rich soil in desert area of Spain and soda lake of Egypt.

DIMTRI SOROKIN TAKING SAMPLES FROM RUSSIAN SODA LAKE

CLAY PARTICLES LOADED WITH BACTERIAL SPORES AND

CALCIUM LACTATE

The bacteria spores and calcium lactate are both embedded in capsules, to prevent interaction before cracks appear.

Electron microscope photograph of bacterial spores

HOW DOES BIOCONCRETE WORK

It uses following chemical reaction in presence of bacterial spores:-

Ca(C3H5O3)2 + 7O2 —>CaCO3 + 5CO2 + 5H2O Calcium Lactate + Oxygen —> Limestone + Carbon Dioxide + Water

5CO2 + 5Ca(OH)2 —> 5CaCO3 + 5H2O Carbon Dioxide + Calcium Hydroxide —> Limestone + Water

Bacterial spores and calcium lactate-containing

specimens consumed substantial amounts of oxygen rapidly after submersion in water.

Schematics of self healing process in baterial concrete

PICTURE OF THE SURFACE OF A SLAB OF SELF HEALING CONCRETE

BEFORE AFTER

PROCESS OF SELF HEALING

(a) 3 days (b) 7 days

(c) 14 days (d) 28 days

(e) 40 days (f) 200 days

PERFORMANCE GRAPH

DISADVANTAGES

THERE IS TWO KEY OBSTACLE

Clay palletes holding self healing agents weakens the concrete by 25% and significantly reduces it’s compessive strengh.

Cost self healing concrete is about double that of conventional concrete.

CONCLUSION

The development of new type of bacteria based self healing concrete appears promising.

Results shows that capsule containing samples showed a significant amount of corrosion inhibition compared to control section.

High crack sealing capacity and healing agent is bio based so it is sustainable.

THANK YOU