Plum Concrete and Its Applications in Industrial Projects

Civil consultants employ plum concrete as a strategic solution to enhance project efficiency, a practice increasingly prevalent in contemporary construction projects. Civil design consultants recommend plum concrete in mass concreting, where stone aggregates of varying sizes, such as 150mm, 200mm, 300mm, or larger, are incorporated into the concrete mix. Factors like application demands, availability, and design specifications determine the stone size. For instance, in applications like gravity dams, bridges, culverts, foundations, and retaining walls, a maximum plum size of 150mm is typically preferred.

Critical Characteristics of Plum

1. Plum stones must possess a minimum crushing strength of 100kg/sq.mm, and various types like trap, basalt, or locally available stones can be used.
2. Plums should be robust, stiff, and durable without weathered surfaces, flaking, or cracking.
3. They must be free from soil, dirt, clay, organic matter, or any detrimental material that could affect the concrete, requiring meticulous handpicking and inspection before use.

Distinguishing Plum Concrete from PCC:

Plum concrete offers an economical solution for mass concrete by incorporating large boulders as fillers, resulting in approximately 30% cost savings compared to traditional Plain Cement Concrete (PCC).

Applications of Plum Concrete:

1. Recommended for mass concreting where PCC thickness is substantial.
2. Suitable for footings under conditions of ground slope ranging from 1:10 to 1:50.
3. They are commonly used in gravity dams, bridges, retaining walls, barriers for bridges and culverts, road barriers with steep slopes, and areas requiring mass concreting on deep or uneven sites.

Plum to Concrete Ratio:

Plum volume in concrete varies based on design specifications. For 150mm-sized plums, the volume typically ranges from 30% to 50%, while for plums larger than 160mm, their volume is limited to 20% of the finished concrete.

Preparation of Plum Concrete:

1. Plum concrete can be prepared by adding plums directly to the concrete mixer or by spreading plums over a concrete layer and placing another layer on top.
2. When adding to the mixer, plum size should not exceed 1/3rd of the cross-section of the mixer.
3. Usually, M10 or M15 grade concrete is employed, adhering to IS456 specifications.

Shuttering & Centering for Plum Concrete:

Shuttering, specified in drawings and specifications, can be achieved using steelwork or plywood shuttering, ensuring strength and durability.

Curing Procedure for Plum Concrete:

As recommended by civil consultants, the curing process typically involves a seven-day curing period to ensure optimal strength and durability.

In conclusion, with its unique characteristics and cost-effective benefits, plum concrete is an integral element in civil engineering, particularly in industrial projects requiring mass concreting and specialized design considerations.