Construction

1. Construction Materials

The main materials used in masonry construction include a variety of bricks and stone units, typically separated by beds and vertical joints comprising some type of mortar.

1.1 Mortars

Types:

• "Traditional" lime based mortars
• Modern cementitious mortars

Mix proportions:

Commonly used in the UK before 1920 and indicative ranges for their compressive strengths, as well as values for the compressive strength of the masonry produced using different brick strengths (assuming standard brick dimensions).

Mortar designation [from BS5628: Part 1]	Type of Mortar (by volume)			Mortar strength range (MPa)	Brick strength (MPa)
Cement: Lime: sand	Masonry:cement:sand	Cement:sand & plasticiser	7	20	35	50	70
Characteristic compressive strength of brickwork (MPa)
(i)
(ii)
(iii)
(iv)
(v)
(vi)
(vii)

1.2 Stone 

Types:

• Sedimentary rocks
• Igneous rocks
• Metamorphic rocks
• Cast Stones

Comparison of typical strength and density values of some common UK building stones with other construction materials (ref BW Heritage Manual)

Masonry unit material	Typical compressive strength (N/mm2)	Typical density (kg/m3)
Stokeground Bath- base bed	22.5	2,126
Stokeground Bath - top bed	13.8	1,988
Portland Roach	52	2,100
Portland Whitbed	36	2,200
Welsh Blue Pennant	158	2,630 - 2,850
Clipsham limestone	32	1,826
Woodkirk Yorkstone	54	2,400
Granites	100 - 350	2,500 - 3,200
Concrete (typical)	40	2,240
Bricks (typical commons)	20	1,800
Bricks (engineering class A)	70	2,800

1.3 Brick

Table of brick types/designations BS5628-Pt3 (updated)

Physical properties of brick samples from old railway structures

	Characteristic strength (N/mm2) (a)	Modulus of elasticity (kN/m2)	Poisson's Ratio (s)
Red and yellow bricks	16.5	5.2	0.11
Blue bricks	70(b)	15.6	0.16

(a) Value exceeded by 90% of bricks tested
(b) value is estimated

 

2. History and Heritage