Modelling of Concrete Performance: Hydration, Microstructure and Mass Transport

by Chaube,Rajesh

• ISBN13: 9780419242000
• ISBN10: 0419242007
• Format: Hardcover
• Copyright: 1999-06-28
• Publisher: CRC Press

Summary

Modelling of Concrete Performacedeals with the long-term performance of concrete. The author describes an integrated theoretical and computational platform from which to examine and assess the quality and structural durability of concrete at an early age. This book will appeal to both the academic and professional.

Table of Contents

Preface	xi
Abstract	xv
Introduction	1	(16)
General	1	(2)
A brief survey of the literature	3	(6)
Microstructure formation and cement hydration	3	(2)
Mass transport	5	(4)
Scope and objectives	9	(4)
Research strategy and outline of this book	13	(2)
References	15	(2)
Assesment of achieved concrete performance and durability design	17	(14)
Introduction	17	(1)
Current practice in durability evaluation	18	(5)
Performance requirements	19	(1)
Prescriptive requirements	20	(3)
Proposal for concrete performance evaluation	23	(5)
Assumptions	25	(1)
Schematics of quantitative evaluation	25	(1)
Implications of the proposal	26	(2)
A case study of durability evaluation	28	(1)
Summary	29	(1)
References	30	(1)
Microstructure formation and hydration phenomena	31	(28)
Introduction	31	(2)
Microstructural development theory	33	(16)
Stereological description of the initial state of mix	33	(3)
Macroscopic volumetric balance of hydration products	36	(2)
Expanding cluster model based on degree of hydration	38	(2)
Surface area of capillary and gel components	40	(4)
Computational model of the total paste microstructure	44	(5)
Multicomponent heat hydration model	49	(8)
Multicomponent concept for heat of hydration of cement	49	(1)
Interaction among cement clinker and pozzolans	50	(3)
The effect of reduced free water and its relationship to moisture transport	53	(2)
Strength development in high-performance concrete	55	(2)
Summary	57	(1)
References	57	(2)
Moisture transport in cementitious materials	59	(48)
Introduction	59	(1)
Coupled liquid and vapour transport formulation	60	(10)
Mass and momentum conservation	61	(4)
Reduction to classical formulation	65	(5)
Isotherms of moisture retention	70	(18)
Thermodynamic equilibrium of phases	71	(3)
Ideal adsorption models and absorption isotherms	74	(4)
Computational model of hysteresis behaviour of isotherms	78	(7)
Interlayer moisture and its contribution	85	(3)
The total moisture isotherm of the hardened matrix	88	(1)
Permeability of concrete	88	(10)
Intrinsic permeability model of a porous medium	90	(2)
Inconsistency in intrinsic permeability observations	92	(2)
Modified water conductivity of concrete	94	(4)
Preliminary verification of intrinsic permeability models	98	(1)
Transport coefficient for unsaturated flows	98	(4)
Liquid conductivity in unsaturated flows	98	(1)
Vapour diffusivity in unsaturated flows	99	(1)
Computational model of moisture conductivity	100	(2)
Varying microstructure in the moisture transport formulation	102	(2)
Summary and conclusions	104	(1)
References	105	(2)
Concerte: a multicomponent composite porous medium	107	(43)
Introduction	107	(1)
Multicomponent of concrete	108	(2)
Hardened cement-paste matrix	108	(1)
Aggregate matrix interfacial zones and bleeding paths	109	(1)
Aggregates	109	(1)
Equilibrium moisture distribution assumption	110	(3)
Percolation of aggregate matrix interfaces	113	(10)
Hard core soft shell computer model	114	(2)
Model results and discussion	116	(4)
Particle size dependent interface model	120	(3)
Moisture transport formulation in a composite	123	(6)
Mass and momentum conservation	123	(3)
Reduction to simplified classical form	126	(3)
Local moisture transport behaviour	129	(3)
Aggegate and fine porosity matrix	131	(1)
Fine porosity matrix and interfaces/channels	131	(1)
Interfaces/channels and aggregates	132	(1)
Simulatios of moisture transport	132	(10)
Sensitivity of local moisture transfer coefficients	134	(4)
Influece of aggregate volume fractions and porosity	138	(4)
Drying shrinkage analysis of lightweight aggregate concrete	142	(5)
Two-dimensional analysis of drying	142	(1)
Drying shrinkage strains	143	(1)
Mass transport equations and numerical scheme	143	(1)
Numerical simulations and verification	144	(3)
Summary and conclusions	147	(1)
References	148	(2)
A simulation model of early age development in concrete: DuCOM	150	(28)
Introduction	150	(1)
Coupled computational formulations	150	(5)
Model features and accuracy considerations	155	(7)
Effect of chemical composition of cement	155	(1)
Effect of cement fineness and particle size distribution	156	(2)
Effect of water-to-cement ratio	158	(1)
Effect of casting temperature	159	(1)
Effect of curing conditions, ambient RH and temperature	160	(2)
Verifications and practical evaluations	162	(14)
Cyclic drying--wetting of mortars	163	(2)
Water sorption in one-dimensional mortars	165	(1)
Predictions of pore structure under severe drying	166	(1)
Prediction of weight loss with time in vacuum drying	166	(3)
Prediction for the effect of various curing conditions on strength development and weight loss	169	(1)
Curing period and quality of cover concrete	170	(3)
Influence of fly ash content on structure and strength development of concrete	173	(3)
Summary and conclusions	176	(1)
References	177	(1)
Multicomponent model for the heat of hydration of Portland cement	178	(71)
Intoduction	178	(12)
Thermal cracking of massive concrete structures	178	(2)
Exothermic hydration process of cement	180	(2)
Adiabatic temperature rise and conventional thermal analysis	182	(2)
Quntification of the exothermic hydration process of cement in concrete (Suzuki model)	184	(4)
Scheme of the multicomponent heat of hydration model	188	(2)
Modellig of the exothermic hydration process	190	(29)
Basic concept of the multicomponent heat of hydration model	190	(4)
Reference heat generation rate of components	194	(4)
Temperature dependence of mineral reactions	198	(3)
Ettringite formation model by reaction of aluminate and ferrite phase with gypsum	201	(4)
Evaluation of interdependence among component reaction	205	(12)
Constitution of the multiple heat of hydration model	217	(2)
Review of adiabatic temperature rise history	219	(9)
Several types of Portland cement	219	(2)
Inverse analysis of thermal activity by using the calculated result of the heat of hydration model	221	(3)
Binary blended cement with blast furnace slag or fly ash	224	(4)
Verification by quasi-adiabatic temperature tests	228	(6)
Experimental outline	228	(1)
Temperature analysis by the heat of hydration model	228	(6)
Verification by thermogravimetric analysis of combined water	234	(5)
Expeimental outline	234	(1)
Analysis by coupled simulation model	235	(4)
Thermal crack control design of mass concrete	239	(7)
Scheme of thermal crack control design	239	(1)
Modelling of strength development	240	(3)
Thermal crack risk and control	243	(3)
Summary and conclusions	246	(1)
References	246	(3)
Conclusons and future development	249	(6)
Appendix A Computation of autogenous and drying shrinkage strains in mortars	255	(17)
A.1 Analytical formulation	256	(3)
A.1.1 Stress due to capillary tension	256	(1)
A.1.2 Unrestrained drying shrinkage strain	257	(1)
A.1.3 Applicability of the model	258	(1)
A.2 Outline of drying shrinkage experiments	259	(1)
A.2.1 Experimental outline	259	(1)
A.3 Experimental results and discussion	260	(5)
A.4 Computational simulation	265	(7)
Appendix B DuCOM on the Internet and its basic specifications	272	(8)
B.1 Material modelling in DuCOM	272	(1)
B.2 DuCOM on the Internet	273	(7)
B.2.1 Content	273	(1)
B.2.2 Key specifications	274	(6)
Appendix C Multicomponent heat generation subroutine for cement in concrete	280	(20)
C.1 Specification of input and output data	280	(4)
C.2 Heat of hydration computation of mineral compounds	284	(3)
C.3 Interaction of hydration process among constituent minerals	287	(1)
C.4 OPC compound hydration routine	288	(6)
C.5 Pozzolan hydration routine (slag and fly ash)	294	(4)
C.6 Total heat of hydration of OPC and mixed cement	298	(1)
C.7 Adiabatic temperature rise	299	(1)
Appendix D BET adsorption model	300	(3)
Index	303