Red bricks are one of the oldest and extensively used building material that is primarily made from clay. Solid concrete blocks are precast concrete blocks manufactured from cement and fine aggregates.

The important difference between red bricks and solid concrete blocks are tabulated below.

Difference between Red bricks and Solid Concrete Blocks

Sl.No Parameter Red Bricks Solid Concrete Blocks
1 Raw Materials Red bricks use the following raw materials: LimeClay or Alumina,Sand,Iron Oxide,Magnesia. The sand used for red brick manufacture is mostly obtained locally. Solid Concrete blocks use the following raw materials: Ordinary Portland Cement,Sand,Gravel, Water. In certain situations, fly ash can be used instead of fine sand.
2 Properties Red bricks are available in modular sizes of 190 x 90 x 90mm and 190 x 90 x 40mm. And also, in Non-modular sizes of 230 x 110 x 70 mm and 230 x 110 x 30mm Standard sizes of solid concrete blocks are of length 400, 500 or 600 mm and height of 200, 100mm and the width from 50, 75, 100, 150, 200,250 or 300 millimeters. The dimension differs from manufacturer to manufacturer.
3 Compressive Strength The compressive strength varies from one class to another and hence lies in the range between 3.5 to 35N/mm2. The compressive strength of solid concrete block varies based on the grade of cement used. Its compressive strength varies from 4 to 5 N/mm2.
4 Dry Density The dry density also varies depending on the class of brick. It normally ranges from 1600 to 1920 kg/m3. The dry density of the solid concrete block is depended on the grade of block. This ranges from 1800 to 2500 kg/m3
5 Water Absorption The water absorption of red bricks is recommended to be less than 20% of its weight Solid concrete blocks must not have a water absorption value not greater than 10% of its weight
6 Thermal Conductivity The thermal conductivity of red bricks is advised to have a value in the range of 0.6 to 1 W/mK. Solid concrete blocks usually have a thermal conductivity in the range 0.7 to 1.28W/mK.
7 Environmental Impact Red bricks utilise clay which is naturaly available. This production hence depletes the top fertile soil. Red bricks also emits more carbon dioxide during its manufacture. The amount of carbon dioxide emitted during the manufacture of solid concrete blocks is less.
8 Mortar Consumption The mortar consumed by red bricks are high due to its irregular surface. Solid concrete blocks have flat and even surface that hence demand less mortar compared to redbricks.
9 Water Usage Curing requires more water Solid concrete blocks require 7 to 14 days of curing which demand high amount of water compared to red bricks.
10 Cost Red bricks alone is cheap. But overall cost including the cost of mortar and construction is high as it demands more mortar. The solid concrete blocks cost high as individual pieces. It consumes less mortar. It have the advantage that the same wall area can be constructed with less number of solid concrete blocks than red bricks.
11 Uses Red bricks can be used as a structural material for the construction of structures like buildings, foundations, arches, pavement and bridges. These can be also used for aesthetic purposes like landscaping, facing works and many other architectural purposes. Solid concrete blocks are employed in construction to act both as load bearing and non-load bearing in walls, panel wall and partition walls. This can also be used as backing for piers, retaining walls, other facing materials, chimneys, fire places and garden walls etc.  

Also Read: Difference between red bricks and Fly ash Bricks