ACT Grouts flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Water-cementitious ratio

Ratio of water weight to cementitious material weight in a grout mix; lower ratios generally increase strength and reduce permeability.

Neat cement grout

A mixture of hydraulic cement and water with no aggregate; used for fine cracks, tendon grouting, and void filling.

Sanded grout

Grout containing fine sand aggregate; used for wider joints and fills where reduced shrinkage and economy are needed.

Non-shrink grout

Grout formulated with expansive additives to offset drying shrinkage, maintaining contact with base plates and anchors.

Bleeding in grout

Upward migration of water to the surface of freshly placed grout; excessive bleed leaves voids and weak zones.

Superplasticizer

Admixture that increases grout flowability without adding water, allowing low water-cement ratio while maintaining placement ease.

Retarder

Admixture that extends grout set time, useful in hot weather or for long placements to prevent premature stiffening.

Laitance

Weak, cement-rich layer on a concrete surface from bleeding; must be removed before grouting to ensure bond.

Saturated-surface-dry

Condition where substrate pores are filled with water but no free water film remains; ideal for grout bond.

Acid etching

Surface preparation using dilute acid to roughen concrete and open pores; followed by thorough flushing before grouting.

Mechanical scarification

Surface roughening by grinding, shot blasting, or scarifying to remove laitance and create bond profile for grout.

Substrate temperature limits

Concrete below about 40 F or above about 90 F affects grout hydration, set time, and shrinkage; adjust protection accordingly.

Curing compound interference

Membrane curing compounds left on a surface can block bond of sealants, toppings, or subsequent grout layers.

Tremie placement

Method of placing grout through a vertical pipe kept submerged in fresh grout to prevent segregation and water washout.

Pressure injection

Grouting method that pumps grout into cracks or voids under controlled pressure until material appears at adjacent vents.

Preplaced-aggregate method

Technique of filling a coarse-aggregate bed by pumping grout from the bottom up, displacing air and water.

Progressive cavity pump

Positive-displacement pump suited to sanded grout; moves material at steady rate with low segregation risk.

Cold joint in grout

Interface formed when fresh grout is placed against grout that has already begun to set; a weak plane unless deliberately formed.

Consolidation by rodding

Mechanical working of fresh grout to release entrapped air; over-vibration can cause segregation and bleeding.

Grout flow cone

Device measuring efflux time in seconds to indicate grout consistency and flowability for placement control.

Wet burlap curing

Moist curing method using continuously wetted burlap to keep grout surface hydrated during early strength gain.

Plastic shrinkage cracking

Cracks that form in fresh grout when surface evaporation exceeds bleed water; controlled by windbreaks, shading, and curing.

Penetrating sealer

Sealer that soaks into grout pores and reacts to repel water while leaving the surface breathable, unlike film formers.

Cold weather grouting

Grouting practice maintaining grout and substrate above about 40 F with heaters and blankets until adequate strength develops.

Evaporation rate factors

Air temperature, grout temperature, relative humidity, and wind speed together determine moisture loss and cracking risk.

Compressive strength specimens

Cube or cylinder samples cast from the placed grout batch and cured under standard conditions to verify mix strength.

Restrained expansion test

Test measuring expansion of non-shrink grout under restraint to confirm it offsets shrinkage and maintains contact.

Sampling at placement

Grout test samples taken at the point of placement rather than the mixer, so results reflect installed material.

Silica dust exposure

Respirable crystalline silica from sanded grout requires dust controls and respiratory protection under OSHA 1926.1153.

Cement chemical burns

Alkaline cement in grout can cause skin and eye burns; gloves, eye protection, and prompt washing are required.

Confined space grouting

Grouting in tanks or vaults requires atmospheric testing, ventilation, and an attendant under OSHA 1910.146.

ASTM C1107

Standard specification for packaged, dry, hydraulic-cement non-shrink grout used for structural and equipment support.