Durability and strength of bond between mortar and brick

Abstract

Durability and strength of bond between the mortar and brick of 1,296 briefer mortar units have been studied. The materials used Included flivs different makes of brick and two different mortars. Alternate freezing and thawing of moisture-saturated units 50 times followed bv drying constituted the tetta for bond durability. Strength of bond was determined after storage of other units for six months under three different conditions. Bond durability WB 100 per cent by loading the units during weathering tests. The factors-pres-sure on the mortar joint, type of mortar used, degree of wetting the brick, and apparent shrinkage of mortar—were of more importance relatively in their effect upon bond strength or durability than properties of the brick themselves, CONTENTS Pngp I . Introduction 474 1. Purpose of the investigation 474 2. Definition of terms 474 3. Materials 475 II. Methods of test 475 1. Total absorption 475 2. Classification of brick shipments 476 3. Rate of absorption 476 4. Preparation of specimens 476 5. Mortars used -476 6. Preparation of units for test 476 7. Test procedure 477 (a) Storage of units -477 (b) Tests for bond durability 479 (c) Strength of bond 479 III. Results -480 1. Durability of bond -481 (a) Durability of bond as affected by the degree of wetting" different brick 4S2 (6) Bond durability as related to brick used 483 (c) Effect of metaf lugs in mortar --488 (d) Durability of bond as related to absorption . . 484 (e) Effect of storage conditions . l s -r > (/) Durability of bond as related to mortar 185 (g) Effect of vertical loading 486 2. Strength of bond ,. ls ' (a) Strength of bond as dependent upon edi-tions -| s7 (6) Strength of bond as related to brick -4^s (c) Strength of bond versus absorption of brick 489 (d) Strength of bond as related to degree of wetting brick.