ANS:E - both (c) and (d).

Hume steel pipes, also known as Hume pipes, are a type of reinforced concrete pipe (R.C.C. pipe) with a steel shell coated both from the inside and outside with cement mortar. Therefore, the correct answer is option (e), both (c) and (d). Let's delve deeper into the characteristics and construction of Hume steel pipes:

1. Steel shell coated from the inside with cement mortar:
   • Hume steel pipes are constructed with a steel shell that serves as the structural reinforcement of the pipe. The steel shell provides strength and durability to the pipe, allowing it to withstand external loads and pressures.
   • To protect the steel shell from corrosion and chemical attack, a layer of cement mortar is applied to the interior surface of the pipe. This cement mortar lining serves as a protective barrier, preventing direct contact between the steel and the conveyed wastewater, which may contain corrosive elements or chemicals.
   • The cement mortar lining also provides a smooth and hydraulically efficient surface for the flow of wastewater, reducing frictional resistance and improving flow characteristics within the pipe.
2. Steel shell coated from the outside with cement mortar:
   • In addition to the interior lining, Hume steel pipes are also coated with cement mortar on the exterior surface of the steel shell. This external coating serves multiple purposes:
     • Protection against external corrosion: The cement mortar coating acts as a protective barrier, shielding the steel shell from environmental factors such as moisture, soil chemicals, and microbial attack, which could lead to corrosion and deterioration of the pipe.
     • Structural reinforcement: The external cement mortar coating helps to enhance the structural integrity of the pipe by providing additional support and resistance to external loads, ground pressures, and mechanical stresses.
     • Aesthetic appearance: The external coating of cement mortar helps to improve the appearance of the pipe and provides a uniform finish that blends with the surrounding environment.
3. Advantages of Hume steel pipes:
   • Durability: Hume steel pipes combine the strength of steel with the durability of reinforced concrete and the protective properties of cement mortar coatings, resulting in a durable and long-lasting pipe material.
   • Corrosion resistance: The dual coating of cement mortar on both the interior and exterior surfaces of the steel shell provides excellent resistance to corrosion, ensuring the longevity of the pipe even in aggressive environments.
   • Hydraulic efficiency: The smooth interior surface of the cement mortar lining reduces frictional resistance and allows for efficient flow of wastewater through the pipe, minimizing head loss and energy consumption.
   • Versatility: Hume steel pipes are suitable for a wide range of applications in sewage systems, stormwater drainage, culverts, and other infrastructure projects, offering versatility and adaptability to various project requirements.

In summary, Hume steel pipes are reinforced concrete pipes with a steel shell coated both from the inside and outside with cement mortar. This construction provides strength, durability, corrosion resistance, and hydraulic efficiency, making them a popular choice for wastewater conveyance and drainage systems.