Hasan Rizvi, Vice President, STP Ltd  speaks of products and mix of chemicals offered by STP that helps make concrete durable and resistant to several environmental factors

 Durable concrete structures can be achieved only through careful attention to many details. Durability is a key determinant for both new construction and repair of old structures. The durability of concrete structures can be defined as their ability to sustain the serviceability for which they were designed. In concrete, quality assurance is a matter of testing and inspecting to ensure the proper selection, proportioning, mixing, handling, placing, and curing of the materials, as well as the appropriate design of the structure itself.

The following points should be taken into account for both the construction of new concrete structures and the repair of old and deteriorated structures:

Factors affecting the durability of structures
•  Poor quality construction
•  Lack of waterproofing treatment
•  Poor maintenance, blocked drain pipes
•  DPC failure
•  Lack of proper slope causing stagnation of water
•  Leaking pipe joints.

Waterproofing of structures
•  Basements (SuperThermolay APP membrane/ STP PVC membrane)
•  Roof  (SuperThermolay APP membrane / STP PVC membrane / ShaliCem EWP)
•  Sunken ( ShaliCrete –R)
•  Planters (STP Hybrid System:  ShaliUrethane LHM  and ShaliCrete-R)
•  Over Head and Underground Tanks (ShaliCem EWP).

Water bodies, fountains (ShaliCem EWP, Injection grouting with ShaliGrout IP)

General concrete deterioration
Most concrete deterioration can be attributed to water penetration. Concrete absorbs moisture until it becomes saturated. When water enters in to the concrete structure it results in spalling of the concrete. Therefore, this needs to be prevented.

Migratory Corrosion Inhibitor, being Amine based bipolar in nature, used as an additive during concreting / Repairs, can protect the steel from corrosion in aggressive environment.
•  Migratory Corrosion Inhibitor  (ShaliPlast RCI)
•  Microconcrete (ShaliFix MC)
•  Epoxy Bonding Agent for joining old and new Concrete (ShaliBond Concrete).

Providing good slopes and effective drainage, it is possible to prevent water from ponding and application of waterproofing treatment thus preventing water from being absorbed. Structure design should accentuate water-shedding characteristics for vertical elements — for example, the proper design detailing of window ledges can prevent the wall from wetting — and incorporate slopes and drain holes for such horizontal elements as decks.

Steel in reinforced concrete is prone to chemical attack in certain corrosive environments.

Sealing the concrete surface with an Acrylic Polymer like ShaliCrete R of STP, widely tested and used for waterproofing and protection of concrete.  Adequate cover helps in protecting reinforcing steel against corrosion. Water cement ratio should be kept as low as possible so as to get a dense concrete which will helps to prevent the ingress of water and water-borne salts, Carbondioxide, Chloride and Sulphurus gases.

STP pioneered solutions for dampness
Procedure consists of removing the plaster from the effected walls upto a height of 1.0 meter, above the affected area.
•  Drilling  holes (18 mm dia, with 125 mm spacing ) along the length of the wall  near the skirting level
•  Each drilled hole will be connected with an inverted bottle filled with silicate base STP Shalimagic (for about two days), height of the bottles should be 1 metre above the drilled hole.

STP products are “Made for India”
In recent past, usage of construction chemicals has increased, as the construction industry had grown on a sustainable basis. The trend is towards liquid applied membranes as they can be applied on any shape of the surface. India has the ability to develop indigenous technologies, processes, rather than importing the technologies. Construction chemical manufacturers like STP Ltd. are promoting durable technologies suitable for our affordability and environment. STP products are suitable for Indian weather and climatic conditions.

Authored by_
Hasan Rizvi,Vice President, STP Ltd