BME Ép.szerk.Tanszék autoclaved aerated concrete (AAC) blocks

© Becker Gábor 2018BME Ép.szerk.Tanszék

raw materials: quartz sand, lime, cement and water + pore forming aggregatemanufacturing: grinding, mixing, maturation in forms, cutting, autoclaving

autoclaved aerated concrete (AAC) blocks

● lightweight, good thermal insulation, several strength (density) classes● exact geometry – 0.25-0.5 cm with (adhesive) mortar – thin joints● block height: 20 cm, length: 50 and 60 cm● wall thickness: 30, 37,5 50 cm ● U-value: 0.27-0.45 0.22-37 0.17 W/mK°

● easy to work with, can be cut with handsaw

AAC building blockswall design, masonry structures – building blocks 2


bonds of building blockswall design, masonry structures – building blocks 5

corner junction bond from fireclay building blocks

separating wall bond fromlimestone brick

separating wall bond from fireclay building blocks

flemish bond


role and function of ring beam

● holding the walls together● bearing horizontal forces (e.g. roof)● distributing concentrated loads (pillar, beam) ● distributing concentrated torque (balcony)● bridging openings (in case of combined ring-beam and

lintel)

full size – beam end is fixed

reduced size – beam resting on the wall

combined with lintel –working together

ring-beamwalls – design of walls, masonry structures – design of masonry structures


2. height (vertical) size coordination

unit: height of a block (m)+ horizontal joint (h)

good, if: - the parapet (PM) - opening's size (NM) - lintel (SZ)

can be divided by the height of a block (m)

M = n x (m+h) = PM + NM + SZ

no cut block is allowed under the prefabricated lintel!

vertical size coordinationwalls – design of walls, masonry structures – design of masonry structures


function, groupingdesign of walls 2 – lintels 1

lintels

function: top delimitation of the openings in walls, and bearing the loads above (door-window openings, mechanical breakthroughs)

grouping by:● form: arched and horizontal● structural design: arches and lintel beams

Ring beam

Lintel

Wall

Opening


flat arch segmental arch semi-circular arch

structurally bent pillar (shape is typical of the architecture of the given era)

arches

force diagram: beam with curved axis, only side pressure can occur in its cross section→ the support should be sized for side (shoulder) pressure

by their shape: with one or two center points

with two center points

walling of arches: like walling of pillars

● for exposed brick cladding

the appearance of the jointis important (carved

bricks, blocks)

archesdesign of walls – lintels 2


arches

walling of arches: like walling of pillars

● for exposed brick cladding the appearance of the joint is

important (carvedbricks, blocks)

archesdesign of walls – lintels 2

carved or key brick wedge-shape gap

small big


lintel beams - bent supports, transfer their loads to the masonry

homogeneouscomplex cross-

section

lintel beamsdesign of walls – lintels – lintel beams

• by material: - steel, - reinforced concrete (RC), - combined (ceramic+RC), aerated concrete+RC, different formwork elements+RC• structural design: - homogeneous or – complexcros-section

• when becomes loadbearing: - at once, - soon, later


● steel beams in the same number as the half-bricks in the wall thickness

● steel beams working together: screwing them together

● can be loaded immediately● any span on demand (dimensioned)● thermal bridge!● reveal design possibilities● fire protection: plaster or coating

● can be loaded immediately● large span (4.80 m)● thermal bridge!● reveal design possibilities

steel beam – at once

prefabricated RC beam - at once

steel, reinforced concretedesign of walls – lintel beams 2


prefabricated RC beam – at once

steel, reinforced concretedesign of walls – lintel beams 2

© Becker Gábor 2017BME Ép.szerk.TanszékCeramic + RC - LATER

ceramic element only tension-zone● load-bearing capacity achieved with masonry

or concrete („D”)● can be loaded only after concrete works got hardened→ support needed

ceramic, formwork elementdesign of walls – lintel beams 3


block-high lintel – at onceceramic form, RC inside● load-bearing capacity achieved in

factory



Formwork elements – not loadbearing!

- AFTER RC GOT HARDENED

● element/unit high● can be loaded only after

concrete got hardened→ support is needed

● additional thermal insulation



partition wallsfunction, features, and grouping of partitions

features: ● self-supporting, non-load-bearing● thin and vibration-sensitive● load to slab● doors, lintels, piping, mechanical and electrical wiring are integrated

partition walls

role (function): internal space division and space separationspace separation: visual, acoustic + mechanical stress special: flat separating wall: Party wall (20 cm RC, 30 cm limestone or more solid ceramic)

grouping ● material: clay, gypsum, plasterboard (+ frame), limestone, aerated concrete, concrete, formwork elements (PS foam, Durisol - wood chips, etc.)● weight: lightweight part. wall <160 kg/m2, heavy part. wall >160 kg/m2

● technology: masonry, attached-bonded, plank, mounted frame-board, monolithic, large panel

● structural construction: homogeneous or multilayer ● structural design: small block, sheets, ceiling-high planks,

room-size board, framed ● plastering: plastered or without plaster (bonded, mounted)


requirements: strength, stiffness, acoustics,- water- and moisture-resistance, formability, possibility of mounting, fixability, load capacity, holding plaster layer

● strength: taking loads from usage - sharp and blunt bumps, even load (30kp/m2), slamming doors ● stiffness: ensuring rigidity even in case of non-displacement-free installation

(only place + wedge) and perforation (doors, mechanical installation)

framed (ribbed)small block plank

requirementspartition walls - overview


water and humidity tolerance: to resist water and moisture permanently● rooms on both sides of the space should be of approx. the same

relative humidity (vapor migration, warping can be=l/600)● sanitary rooms: wall insulation or installation of watertight cladding

acoustic: meet the requirements of air-borne sound insulation (RW depending on the function of separated rooms)

● acoustically: single-leaf, double-leaf● enclosure structure should be heavy but flexible● only few sound bridges allowed (flanking transmission: slab and wall

joints)

double-leafsingle-leaf

homogeneous wall

sound absorbing layer

partition wall

leaf

requirements 2partition walls - overview


shape and size tolerance:degree of length, width, thickness and angle deviation, edge curvature,

plane curvature should comply with the specificationsholding plaster finish:

frequent vibrations from use → only partition with suitable surface roughness (corrugation) can hold plaster

formability (cutting), fixability

● allow the reception of additional structures (socket, plinths, switches, plug sockets, lighting fixtures, etc.)

● reception of furniture and equipment of use (shelves, pictures), without damaging deformation● reception of mechanical equipment and wiring of the intended purpose

traditional mounting panel

requirements 3partition walls - overview

it is forbidden to integrate wire into the wall of residential and office premises designed for human habitation (even from the other side)!


partitions requiring plaster finish

● small brick, double brick, masonry

small block masonry partitions requiring plaster finish 1

half-brick shiner wall - brick laid on the long narrow side - barge position

folding wedges


● walled from partition blocks

walled from partition blocks partitions requiring plaster finish 2

fire-clay

fine ceramic

AAC

folding wedges


● walled from partition blocks

walled from partition blocks partitions requiring plaster finish 2

plasterboard, floor-high plankspartitions with no need of plastering 2

● plank-like, attached and bonded

hollow-section gypsum-perlite plank

gypsum ribbed plasterboard plank

T


● large-size panels, floor-high partitions

● wall-size monolithic cement-steel mesh partitions

large-size, cement-steel meshpartitions with no need of plastering 3


versions - various partitionspartitions

© Becker Gábor 2017BME Ép.szerk.Tanszékapartment separating wall – PARTY WALL

role (function): space separation between two apartments

requirements: as for partition walls, but stronger mechanical and acoustic requirements: R’

W + C = 52 dB can be made from: 20 cm RC, 25-30 cm sandlime or heavy clay blockLOAD on slab: dimensioned beam!

Inserting into the wall is acoustically much more favorable!

slab connection: with soft acoustic plate

sandlime blockceramic

apartment separating wallhigh performance partition wall

overview floors - requirements, groupings

floors - purpose, flat floors and vaults

classification by ● material, ● technology, ● structural design, ● staticalscheme, ● rebars, ● position within the building

grouping of floors based on their structural design

parts of the floor (broader sense): load-bearing + floor structure

requirements for floors

● strength● durability● waterproofing● thermal insulation


● fire resistance requirements ● special requirements: vibration resistance, electrostatic charge

protection, transparency ● possibility of wire installation

● acoustic insulation

function, flat and vault floorsfloors - requirements, groupings

flat floors vaults

supported along one or more lines or point by point

transfers loads (shear forces, moments) to the walls/pillars

curved surfacetransfers loads with vault-pressure

to the retaining walls/pillars

according to the shape of the enclosure slabs (their load-bearing structures) can be

floor: space separating (covering) structure supported by walls or pillars; typically horizontal and flat, less often curved, occasionally inclined

purpose (function): space separation → load-bearing

secondary function: stiffening, optional: acoustic insulation, thermal insulation,waterproofing (precipitation or sanitary water)


*

flat and vault floors – examplesfloors - requirements, groupings


material technology structure

RC concrete

monolith, semi-

monolith prefab.

slab, row of beams, beam

steel mounted beam

timber mounted row of beams, beam

brick, stone

masonry vault

(roof)

roof

intermediate

basement

arcade

groupings of floors (their load-bearing structures) by● material● technology● structural design● static scheme● reinforcement● position within the building

.

statical scheme reinforcement positionone-way load-

bearingmild steel

bars roof

two-way load-bearing pre-stressed basement

dual supported post-stressed intermediate

Multiple support arcade

groupingsfloors - requirements, groupings


*


grouping of floors based on their structural design

beam floors

floors with beam

floors with closely placed ribs

floors with closely placed rib and hollow block

monolithic slabs

concrete panel slabs

structural designfloors - groupings 2


parts of the floor (broader sense): load-bearing + floor structure

the complete floor structure can include:

filling thermal insulation sound insulation

waterproofed slab double-layer floor suspended ceiling

filling thermal insulation sound insulation

waterproofing raised floor suspended ceiling

constructionfloors - the construction of the entire floor structure



requirements for floors : strength, sound insulation, thermal insulation, waterproofing (precipitation or sanitary water), fire resistance, special requirements, possibility of wire installation

strength: floors must always be dimensioned!

loads: ● permanent loads

(self-weight + weight of partitions)

● Useful (first three: live) loads: apartment - 1.5 kN/m2

office - 2 kN/m2

classroom - 3 kN/m2

snow load: p = h x γwind load: p = c x pt = c x γ/2 x ω2

(air density)

(speed)

strength – loadsrequirements for floors 1


determining cross section dimensions, size estimation

for prefabricated structures: MM < MH (kNm), q M < q H (kN/m)

monolithic structures - rules of thumb to estimate dimensions

beam:● dual supported

● multiple-supported

slab:● dual supported

● multiple-supported

h =

l 0

25

l 0

20

h =

v =

l 0

35-40

l 0

30

v =

strength - dimension estimationrequirements for floors 2

*


interpretation of partial fixing:

deflection - requirement: maximum allowed deflection

affected by: load, span, the inertia of the support, the elasticity of its material

monolithic and prefabricated slabs behave differently for deformations

deflection limits for HQ buildings l /400 - l /600 for other structures l /300

strength - fixed end, deflection requirements for floors 3

*


working together: distribution of the concentrated load on the slab to the adjacent elements (beams)

advantage: smaller load on one support, smaller cracks, provides reserve,e.g. no reinforcement is needed at reconstructions

measurement: ratio - it is good if V > 50 % (transmitted load)

for monolithic floors easy to solve, for prefabricated slabs can be solved only with additional structures (cross rib)

interpretation of together working and its additional

structures

strength - together workingrequirements for floors 4


multiple-support - for multi-span roofs → smaller moment, deflection andcrackfor monolithic floors easy to solve, for prefabricated slabs can be solved only with additional structures

durability requirements: - physical wear (should be a durable structure)- moral wear (consistency of structure, function and modernity, obsolescence)

waterproofing requirements:- always needed for roof floors (precipitation effect)- for intermediate floors: in case of group shower, or special technology- for balconies: protection of built-in layers (frost damages) and bottom surface

(plastering)

multiple-supporting, durability, water-proofingrequirements for floors 5

© Becker Gábor 2017BME Ép.szerk.Tanszékthermal insulation requirements:

● always needed for floors separating spaces with differenttemperatures

● for structures joining the slab, being in contact with outdoor space (to prevent thermal bridge)

slabs thermal transmittancerequirements:

flat roof U=0,17 W/m2Karcade U=0,25 W/m2K attic floor U=0,17 W/m2K basement floor U=0,26 W/m2K

thermal insulationrequirements for floors 6


floors by their acoustic (structure-borne sound insulation) operation

contact floors

composite (multilayer) flooring

soft floorhard floor

tilingadhesive

wall-to-wall carpet, pvcfoam underlay

flooringbase concrete

floating layerslab

parquet

vibration insulating underlaying

sound absorbing filling

sleeper

slab slab

flexible floor floating floor

acoustical operation of floorsrequirements for floors 8 - sound insulation

T


fire protection features of construction products

goal: maintaining the building's stability for a specified period of time, limiting the spread of fire, serving the safety of escape and rescue

classification methods: ● fire class (reaction-to-fire) – description of the fire behavior of a building material or

a construction product (flammability - how difficult it is to ignite, rate of smoke development, burning dripping)A1, A2 B, C, D, E (F) s1, s2, s3 d0, d1, d2

● fire resistance limit – duration for which a building structure withstands the fire impact (R, E, I performance features + duration in minute – 15…240 minutes)

load-bearing capacity in case of fire

preservation of integrity (burning through)

thermal insulation capacity in case of fire

fire protection features of construction productswalls – requirements for walls – fire protection 2

fire protection requirements for floors

classification:● intermediate floor (general)● basement floor (increased requirement)● fire-retardant slab (around fire compartment)● roof support structure (bar-like elements (beam) - not space separation)● space separating structure of roof slab (structures of surface weight below 60

kg/m2 - sandwich panels, layers constructed on corrugated steel sheet)

examples of requirements:

floor type

building risk level and number of floors

Very Low,B+GF+R

Low, B+GF+2 Middle, B+GF+4

basement floor A2, REI 30 A2, REI 45 A2, REI 60

intermediate floor D, REI 15 C, REI 30 A2, REI 45

fire-retardant slab

A2, REI 30 A2, REI 30 A2, REI 60

fire protection requirementsrequirements for floors 12 - fire protection


Documents

BME Ép.szerk.Tanszék autoclaved aerated concrete (AAC) blocks