How to Improve Pump ability of Lightweight Aggregate Concrete?

In this article, we will discuss how to improve pump ability of lightweight aggregate concrete.

Lightweight concrete can be defined as a type of concrete that has a density of less than 1920kg/m³.

Lightweight concrete is also commonly referred to as cellular concrete.

This type of concrete contains a mixture of lightweight coarse aggregates, fine aggregates, binding material, and water in a definite proportion.

The lightweight aggregates that are commonly used include expanded shale, clay, and other similar materials that have been burned in a rotary kiln and thus have developed a porous structure.

Sometimes, blast furnace slag is also used as aggregate for lightweight concrete.

Mostly, the density of the lightweight concrete may vary between 1440kg/m³ to 1840kg/m³.

Some of the uses of lightweight concrete can be listed as follows:

a. It is extensively used for the screeds and thickening purposes such as the thickening of roofs, floors, etc.

b. It can be used for the casting of structural steel to prevent it from fire hazards, corrosion, etc.

c. It can be used for heat insulation on roofs as well as for the insulation of water pipes and walls.

d. It can be used for the construction of general partition walls and panel walls in the frame structures.

e. It can be used for the surface rendering of external walls in residential buildings.

f. The possibility of spalling is relatively lower in lightweight concrete.

Some of the advantages of lightweight concrete can be listed as follows:

a. The lightweight concrete greatly reduces the dead load and thus allows a longer span.

b. The decreased dead load also ensures lower haulage and handling costs and thus a faster construction rate can be achieved.

c. The use of lightweight concrete in the construction of floors, partition walls, external cladding, and other structural members of the frame structures can offer greater flexibility in design and also save the time and cost of construction.

d. Due to the low thermal conductivity of lightweight concrete, it can be used for insulation works.

However, a major disadvantage of lightweight concrete is that the depth within which corrosion can occur is nearly twice that of normal concrete.

  1. How to Improve Pump ability of Lightweight Aggregate Concrete?  

Here are a few ways on topic of How to Improve Pump ability of Lightweight Aggregate Concrete that you can try are as follows: 

a. Lightweight aggregate has more increased water absorption than conventional aggregate, and pump pressure further expands its water absorption capacity. Therefore, the addition of water is one of the steps to enhance the pumping ability of lightweight concrete.

b. However, the above measure is not always sufficient since some weaknesses of the concrete mix cannot be overcome by keeping water in the mixture. The priority should be on controlling water loss in the concrete mixture.

c. Saturate the lightweight aggregate before batching by the process of sprinkling, immersion of partially cooled aggregate in water, or vacuum saturation. Satisfactory saturation minimizes slump loss, maintains mix consistency, and improves pump ability.

d. In the possibility of sprinkling, the lesser time for effective saturation of lightweight aggregate is constant and continuous sprinkling is needed for a minimum of three to seven days.

e. The concrete mix should include a minimum of 335 Kg of cement per cubic meter.

f. Utilize pumping aid or water-reducing admixture. For instance, expanded shale aggregate concrete mix can be enhanced by improving air content from 4% to 8% and replacing some sand with fly ash.

g. Remove a diminutive quantity of coarse aggregate with sand.

h. Employ a slump of 10 cm to 15 cm. If needed, add cement to the mixture to preserve this high slump.

i. The natural sand in the mix should be well-graded with a fineness modulus ranging from 2.2 to 2.7. If the used sand does not satisfy these requirements, add the sand content.

j. Grade coarse and fine aggregate properly utilizing absolute volume rather than mass to account for differences in relative density of the different particle sizes.

k. About pumping equipment, operate the largest size line available (minimum 125 mm diameter), control rapid size decrease, and reduce pumping pressure through limiting bend number, utilizing steel line rather than rubber line, and delaying down placement rate.

Hope you got the answer to How to Improve Pump ability of Lightweight Aggregate Concrete.