Developing new building materials and construction technologies
Development of Durable Concretes using High Volumes of Cement Replacement Materials (HV-CRMs)
- Explored the utilization of HV-CRMs to extend the gains of cement reduction, enhanced durability, conservation natural resources & mitigation of damage to ecology.
- Mixes with 1)same binder content (constant w/b) or 2)increased binder (reduced w/b) developed- upto 70% GGBS or 50% FA for M30- M40 grades.
- 10 to 15% of SF boosts the properties in case of HV- FA (- Triple blends).
- Benefits- Drastic modification of micro structure, reduced H2O absorption, cl- ingress, H2O permeability sulphate attack & Corrosion.
- Effectiveness of ground and ultra fine FA
Assessment of Early Age Stiffening and Strength of Concrete Mixtures
- Very important for deciding de-shuttering schedule in modern fast-track constructions -problems with interaction & in-compatibility of multi-ingredient mixtures
- Techniques – Pin penetration, strength tests, US signature analysis & Maturity.
- US Pulse captured using a Digital Oscilloscope & analyzed wrt peak amplitude, wave energy, and attenuation (FFT)
- Peak amplitude & attenuation showed higher correlation & better depicted the growth of strength with age
- Maturity approach used for varying temperature histories
- The Hansen and Kim theory, yielded the best prediction
- Formulated an approach for strength prediction at different ages and temperature histories using attenuation and maturity measurement
High Performance Concrete for Construction of Pavements
- M40, M50 and M60 mixes with 50% FA & Fiber (steel/polymer) developed
- Flexural strengths up to 9 MPa suitable for ultra-thin white topping (<100mm) obtained.
- Toughness index (I30) – 21 – 30 for SFRC and 7 – 20 for Polymer fibers.
- Transport properties- Water absorption and Cl- diffusion substantially reduced(nearly one order less).
- Incorporation of Polymer fibers substantially reduced plastic, drying and restrained shrinkage.
- Considerable delay in development and widening of cracks & their width, Increased no of well behaved cracks.
- Improved wear resistance and improved riding comfort.
Drying Shrinkage Ring Shrinkage Plastic Shrinkage Test on Panels
Precast FACC Piles Driving and Testing
Investigations on Effect of Silica Fume in Concrete
- Evaluated the effectiveness of densified and undensified SF on concretes with/ without FA.
- Parameters : Cement grade, SF dosage, workability & curing protocols.
- Assessed- strength at different ages & transport corrosion resistance & pore refinement.
- Significant improvement by addition of SF, USF – better performance.
- Evaluated autogenous & drying shrinkage of pastes. Careful curing emphasised.
- Triple blend advantages brought out- effective utilization of HVCRMs- use of SF in a prestigious construction (parliamentary library).
